Develop Reference

App crashes after theme change (apparently caused by fragment)

My Main Activity has three tabs. Each tab is a fragment. Now if you change the theme (white and dark are available), the activity is being recreated so that the change takes effect. But the app crashes.
How I deal with the fragments:
if (savedInstanceState == null) {
pageadapter = new SectionsPageAdapter(getSupportFragmentManager());
rFragMore = new RoomlistFragmentMore();
rFragMyRooms = new RoomlistFragmentMyRooms();
rFragFavs = new RoomlistFragmentFavorites();
} else {
rFragMyRooms = (RoomlistFragmentMyRooms)pageadapter.getItem(0);
rFragFavs = (RoomlistFragmentFavorites)pageadapter.getItem(1);
rFragMore = (RoomlistFragmentMore)pageadapter.getItem(2);
pageadapter.clearAdapter();
pageadapter = new SectionsPageAdapter(getSupportFragmentManager());
}
How I set up the Adapter:
private void setupViewPager(ViewPager viewPager) {
pageadapter.addFragment(rFragMyRooms, getResources().getString(R.string.myrooms));
pageadapter.addFragment(rFragFavs, getResources().getString(R.string.favorites));
pageadapter.addFragment(rFragMore, getResources().getString(R.string.more));
viewPager.setAdapter(pageadapter);
}
My Adapter:
public class SectionsPageAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public void addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
public void clearAdapter() {
mFragmentList.clear();
mFragmentTitleList.clear();
}
public SectionsPageAdapter(FragmentManager fm) {
super(fm);
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
#Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
#Override
public int getCount() {
return mFragmentList.size();
}
}
And the Error Log:
java.lang.NullPointerException: Attempt to invoke virtual method 'java.io.FileInputStream android.content.Context.openFileInput(java.lang.String)' on a null object reference
at com.yannick.mychatapp.RoomlistFragmentMore.readFromFile(RoomlistFragmentMore.java:246)
at com.yannick.mychatapp.RoomlistFragmentMore.addRoomToList(RoomlistFragmentMore.java:121)
at com.yannick.mychatapp.RoomlistFragmentMore.access$000(RoomlistFragmentMore.java:46)
at com.yannick.mychatapp.RoomlistFragmentMore$1.onDataChange(RoomlistFragmentMore.java:79)
at com.google.firebase.database.core.ValueEventRegistration.fireEvent(com.google.firebase:firebase-database##16.0.4:75)
at com.google.firebase.database.core.view.DataEvent.fire(com.google.firebase:firebase-database##16.0.4:63)
at com.google.firebase.database.core.view.EventRaiser$1.run(com.google.firebase:firebase-database##16.0.4:55)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6669)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
EDIT: the code of RoomlistFragmentMore
public class RoomlistFragmentMore extends Fragment {
private ListView listView;
private List<HashMap<String, String>> listItems = new ArrayList<>();
private String raumname, theme;
private static String userID = "";
private SimpleAdapter adapter;
private DatabaseReference root = FirebaseDatabase.getInstance().getReference().getRoot().child("rooms");
private ArrayList<Room> raumliste = new ArrayList<>();
private TextView keinraumgefunden;
private String[] kat;
private static final String TAG = "RoomlistFragmentMore";
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.roomlist_fragment_more,container,false);
listView = view.findViewById(R.id.listView);
keinraumgefunden = view.findViewById(R.id.keinraumgefunden);
kat = getResources().getStringArray(R.array.categories);
theme = readFromFile("mychatapp_theme.txt");
adapter = new SimpleAdapter(getActivity(), listItems, R.layout.listlayout,
new String[]{"name", "kat", "lock", "newest"},
new int[]{R.id.raumname, R.id.raumkat, R.id.raumlock, R.id.raumdatum});
listView.setAdapter(adapter);
root.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
addRoomToList(dataSnapshot);
}
#Override
public void onCancelled(DatabaseError databaseError) {
Toast.makeText(getActivity(), R.string.nodatabaseconnection, Toast.LENGTH_SHORT).show();
}
});
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
int position = listView.getPositionForView(view);
String roomname = listItems.get(position).values().toArray()[0].toString();
Room room = findRoom(raumliste, roomname);
request_password(room, position);
}
});
adapter.registerDataSetObserver(new DataSetObserver() {
#Override
public void onChanged() {
if (raumliste.isEmpty()) {
keinraumgefunden.setText(R.string.noroomfound);
} else {
keinraumgefunden.setText("");
}
}
});
return view;
}
private void addRoomToList(DataSnapshot dataSnapshot) {
HashMap<String, String> raeume = new HashMap<>();
raumliste.clear();
for(DataSnapshot uniqueKeySnapshot : dataSnapshot.getChildren()){
String name = uniqueKeySnapshot.getKey();
for(DataSnapshot roomSnapshot : uniqueKeySnapshot.getChildren()){
Room room = roomSnapshot.getValue(Room.class);
room.setRaumname(name);
if (!room.getPasswd().equals(readFromFile("mychatapp_raum_" + name + ".txt"))) {
raeume.put(name, kat[Integer.parseInt(room.getCaty())]+"/"+"\uD83D\uDD12"+"/");
raumliste.add(room);
}
break;
}
}
listItems.clear();
Iterator it = raeume.entrySet().iterator();
while (it.hasNext()){
HashMap<String, String> resultsMap = new HashMap<>();
Map.Entry pair = (Map.Entry)it.next();
resultsMap.put("name", pair.getKey().toString());
String daten = pair.getValue().toString();
String caty = daten.substring(0, daten.indexOf("/"));
String lock = daten.substring(daten.indexOf("/")+1, daten.lastIndexOf("/"));
String time = daten.substring(daten.lastIndexOf("/")+1, daten.length());
String newestTime = "";
int index = 0;
resultsMap.put("kat", caty);
resultsMap.put("lock", lock);
resultsMap.put("newest", newestTime);
if (time.equals("")) {
listItems.add(resultsMap);
} else {
listItems.add(index, resultsMap);
}
}
adapter.notifyDataSetChanged();
}
private void request_password(final Room room, final int position) {
LayoutInflater inflater = LayoutInflater.from(getContext());
View view = inflater.inflate(R.layout.enter_room, null);
raumname = room.getRaumname();
userID = readFromFile("mychatapp_userid.txt");
final EditText input_field = view.findViewById(R.id.room_password);
AlertDialog.Builder builder;
if (theme.equals(getResources().getStringArray(R.array.themes)[1])) {
builder = new AlertDialog.Builder(new ContextThemeWrapper(getActivity(), R.style.AlertDialogDark));
} else {
builder = new AlertDialog.Builder(getActivity());
}
builder.setTitle(R.string.pleaseenterpassword);
builder.setView(view);
builder.setCancelable(false);
builder.setPositiveButton(R.string.confirm, new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
}
});
builder.setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
View view = ((AlertDialog) dialogInterface).getCurrentFocus();
if (view != null) {
InputMethodManager imm = (InputMethodManager)getActivity().getSystemService(Context.INPUT_METHOD_SERVICE);
imm.hideSoftInputFromWindow(view.getWindowToken(), 0);
}
dialogInterface.cancel();
}
});
final AlertDialog alert = builder.create();
alert.setOnShowListener(new DialogInterface.OnShowListener() {
#Override
public void onShow(DialogInterface dialog) {
Button b = alert.getButton(AlertDialog.BUTTON_POSITIVE);
b.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if (input_field.getText().toString().trim().equals(room.getPasswd())) {
Intent tabIntent = new Intent("tab");
LocalBroadcastManager.getInstance(getActivity()).sendBroadcast(tabIntent);
Intent intent = new Intent(getActivity(), ChatActivity.class);
intent.putExtra("room_name", room.getRaumname());
intent.putExtra("user_id",userID);
updateRoomList(position);
writeToFile(room.getPasswd(),"mychatapp_raum_" + raumname + ".txt");
alert.cancel();
startActivity(intent);
} else {
Toast.makeText(getActivity(), R.string.wrongpassword, Toast.LENGTH_SHORT).show();
}
}
});
}
});
alert.show();
}
public Room findRoom(ArrayList<Room> raumliste, String raumname) {
for (Room room : raumliste) {
if (room.getRaumname().equals(raumname)) {
return room;
}
}
return null;
}
public void writeToFile(String text, String datei) {
Context context = getActivity();
try {
OutputStreamWriter outputStreamWriter = new OutputStreamWriter(context.openFileOutput(datei, Context.MODE_PRIVATE));
outputStreamWriter.write(text);
outputStreamWriter.close();
}
catch (IOException e) {
Log.e("Exception", "File write failed: " + e.toString());
}
}
public String readFromFile(String datei) {
Context context = getActivity();
String erg = "";
try {
InputStream inputStream = context.openFileInput(datei);
if ( inputStream != null ) {
InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
String receiveString = "";
StringBuilder stringBuilder = new StringBuilder();
while ( (receiveString = bufferedReader.readLine()) != null ) {
stringBuilder.append(receiveString);
}
inputStream.close();
erg = stringBuilder.toString();
}
}
catch (FileNotFoundException e) {
Log.e("login activity", "File not found: " + e.toString());
} catch (IOException e) {
Log.e("login activity", "Can not read file: " + e.toString());
}
return erg;
}
private void updateRoomList(int position) {
listItems.remove(position);
adapter.notifyDataSetChanged();
}
}

The NullPointerException occured while onDataChange() was executed (you can see this by reading the stack trace). More specifically, readFromFile() needs a valid Context to open a file.
Since your app crashed we know that getActivity() did return null. How can this happen?
You add the ValueEventListener in onCreateView(). At this point in time, the Fragment has a valid Context (see the documentation for an explanation of the Lifecycle), so all is well for the moment.
But since you do not remove the ValueEventListener, it will continue to fire even if the Fragment is temporarily not attached to the Activity because the user swiped to the next page. The Fragment won't be garbage collected because you keep it in a list and reuse it.
This approach is basically ok if you implement null checks to avoid accessing the Activity, the Context or Views in general while they are not present. Of course, you could consider a stronger separation of the data and the View layer as suggested in this guide to app architecture

Unable to play video in Wowza GoCoder's PlayerActivity

I keep getting an an error when trying to call WowZa GoCoder SDK's PlayerActivity and I am unable to understand the cause. The error appears when mStreamPlayerView.play(mStreamPlayerConfig, statusCallback) is called. Would really appreciate help on where i am going wrong
vodFragment.java
public class vodFragment extends Fragment {
private int mColumnCount = 1;
ListView videoView;
ArrayList <Vidoes> videoList;
private static String value;
String videoName;
String url = "http://192.168.43.149/twende/channelVOD.php";
public vodFragment() {
}
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
if (getActivity().getActionBar() != null) {
getActivity().getActionBar().setTitle(value);
}
View view = inflater.inflate(R.layout.fragment_vod_list, container, false);
videoView = (ListView) view.findViewById(R.id.listView);
videoList = new ArrayList<Vidoes>();
JSONObject channelInfo = new JSONObject();
try {
channelInfo.put("channelName", value);
channelInfo.put("channelOwner", "dan");
postJSONObject(url,channelInfo);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return view;
}
public static void setChannel(String channel){
value = channel;
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
}
#Override
public void onDetach() {
super.onDetach();
}
public void postJSONObject(final String myurl, final JSONObject parameters) {
class postJSONObject extends AsyncTask<Void, Void, String> {
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
try {
loadIntoVodView(s);
} catch (Exception e) {
e.printStackTrace();
}
}
#Override
protected String doInBackground(Void... voids) {
HttpURLConnection conn = null;
try {
StringBuffer response = null;
URL url = new URL(myurl);
conn = (HttpURLConnection) url.openConnection();
conn.setReadTimeout(10000);
conn.setConnectTimeout(15000);
conn.setRequestProperty("Content-Type", "application/json");
conn.setDoOutput(true);
conn.setRequestMethod("POST");
OutputStream out = new BufferedOutputStream(conn.getOutputStream());
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(out, "UTF-8"));
writer.write(parameters.toString());
writer.close();
out.close();
int responseCode = conn.getResponseCode();
System.out.println("responseCode" + responseCode);
switch (responseCode) {
case 200:
BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
String inputLine;
response = new StringBuffer();
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
in.close();
return response.toString();
}
} catch (IOException ex) {
ex.printStackTrace();
} finally {
if (conn != null) {
try {
conn.disconnect();
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
return null;
}
}
postJSONObject postJSONObject = new postJSONObject();
postJSONObject.execute();
}
private void loadIntoVodView(String json) throws JSONException {
JSONArray jsonArray = new JSONArray(json);
final String[] videos = new String[jsonArray.length()];
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject obj = jsonArray.getJSONObject(i);
videos[i] = removeExtension(obj.getString("title"));
Vidoes vidoe = new Vidoes();
vidoe.setTitle(videos[i]);
videoList.add(vidoe);
}
VideoListAdapter adapter = new VideoListAdapter(getActivity(), R.layout.vodparsedata, videoList);
videoView.setAdapter(adapter);
videoView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> arg0, View arg1,
int position, long arg3) {
videoName = Arrays.asList(videos).get(position);
Intent intent = new Intent(getActivity(), PlayerActivity.class);
String message = videoName+".mp4";
intent.putExtra("videoName", message);
startActivity(intent);
System.out.println("arr: " + Arrays.asList(videos).get(position));
}
});
}
public static String removeExtension(String fileName) {
if (fileName.indexOf(".") > 0) {
return fileName.substring(0, fileName.lastIndexOf("."));
} else {
return fileName;
}
}
}
PlayerActivity.java
public class PlayerActivity extends GoCoderSDKActivityBase {
final private static String TAG = PlayerActivity.class.getSimpleName();
String videoName;
private WOWZPlayerView mStreamPlayerView = null;
private WOWZPlayerConfig mStreamPlayerConfig = new WOWZPlayerConfig();
private MultiStateButton mBtnPlayStream = null;
private MultiStateButton mBtnSettings = null;
private MultiStateButton mBtnMic = null;
private MultiStateButton mBtnScale = null;
private SeekBar mSeekVolume = null;
private ProgressDialog mBufferingDialog = null;
private StatusView mStatusView = null;
private TextView mHelp = null;
private TimerView mTimerView = null;
private ImageButton mStreamMetadata = null;
private boolean mUseHLSPlayback = false;
private WOWZPlayerView.PacketThresholdChangeListener packetChangeListener = null;
private VolumeChangeObserver mVolumeSettingChangeObserver = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_stream_player);
mRequiredPermissions = new String[]{};
if (savedInstanceState == null) {
Bundle extras = getIntent().getExtras();
if(extras == null) {
videoName= null;
} else {
videoName= extras.getString("videoName");
}
} else {
videoName= (String) savedInstanceState.getSerializable("videoName");
}
System.out.print(videoName);
mStreamPlayerConfig.setIsPlayback(true);
mStreamPlayerConfig.setHostAddress("192.168.43.149");
mStreamPlayerConfig.setApplicationName("Dark Souls 2 Channel");
mStreamPlayerConfig.setStreamName(videoName);
mStreamPlayerConfig.setPortNumber(1935);
mStreamPlayerView = (WOWZPlayerView) findViewById(R.id.vwStreamPlayer);
mBtnPlayStream = (MultiStateButton) findViewById(R.id.ic_play_stream);
mBtnSettings = (MultiStateButton) findViewById(R.id.ic_settings);
mBtnMic = (MultiStateButton) findViewById(R.id.ic_mic);
mBtnScale = (MultiStateButton) findViewById(R.id.ic_scale);
mTimerView = (TimerView) findViewById(R.id.txtTimer);
mStatusView = (StatusView) findViewById(R.id.statusView);
mStreamMetadata = (ImageButton) findViewById(R.id.imgBtnStreamInfo);
mHelp = (TextView) findViewById(R.id.streamPlayerHelp);
mSeekVolume = (SeekBar) findViewById(R.id.sb_volume);
WOWZStatusCallback statusCallback = new StatusCallback();
mStreamPlayerView.play(mStreamPlayerConfig, statusCallback);
mTimerView.setVisibility(View.GONE);
mStreamPlayerView.play(mStreamPlayerConfig, statusCallback);
if (sGoCoderSDK != null) {
/*
Packet change listener setup
*/
final PlayerActivity activity = this;
packetChangeListener = new WOWZPlayerView.PacketThresholdChangeListener() {
#Override
public void packetsBelowMinimumThreshold(int packetCount) {
WOWZLog.debug("Packets have fallen below threshold "+packetCount+"... ");
activity.runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(activity, "Packets have fallen below threshold ... ", Toast.LENGTH_SHORT).show();
}
});
}
#Override
public void packetsAboveMinimumThreshold(int packetCount) {
WOWZLog.debug("Packets have risen above threshold "+packetCount+" ... ");
activity.runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(activity, "Packets have risen above threshold ... ", Toast.LENGTH_SHORT).show();
}
});
}
};
mStreamPlayerView.setShowAllNotificationsWhenBelowThreshold(false);
mStreamPlayerView.setMinimumPacketThreshold(20);
mStreamPlayerView.registerPacketThresholdListener(packetChangeListener);
///// End packet change notification listener
mTimerView.setTimerProvider(new TimerView.TimerProvider() {
#Override
public long getTimecode() {
return mStreamPlayerView.getCurrentTime();
}
#Override
public long getDuration() {
return mStreamPlayerView.getDuration();
}
});
mSeekVolume.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
if (mStreamPlayerView != null && mStreamPlayerView.isPlaying()) {
mStreamPlayerView.setVolume(progress);
}
}
public void onStartTrackingTouch(SeekBar seekBar) {
}
public void onStopTrackingTouch(SeekBar seekBar) {
}
});
// listen for volume changes from device buttons, etc.
mVolumeSettingChangeObserver = new VolumeChangeObserver(this, new Handler());
getApplicationContext().getContentResolver().registerContentObserver(android.provider.Settings.System.CONTENT_URI, true, mVolumeSettingChangeObserver);
mVolumeSettingChangeObserver.setVolumeChangeListener(new VolumeChangeObserver.VolumeChangeListener() {
#Override
public void onVolumeChanged(int previousLevel, int currentLevel) {
if (mSeekVolume != null)
mSeekVolume.setProgress(currentLevel);
if (mStreamPlayerView != null && mStreamPlayerView.isPlaying()) {
mStreamPlayerView.setVolume(currentLevel);
}
}
});
mBtnScale.setState(mStreamPlayerView.getScaleMode() == WOWZMediaConfig.FILL_VIEW);
// The streaming player configuration properties
mStreamPlayerConfig = new WOWZPlayerConfig();
mBufferingDialog = new ProgressDialog(this);
mBufferingDialog.setTitle(R.string.status_buffering);
mBufferingDialog.setMessage(getResources().getString(R.string.msg_please_wait));
mBufferingDialog.setButton(DialogInterface.BUTTON_NEGATIVE, getResources().getString(R.string.button_cancel), new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
cancelBuffering(dialogInterface);
}
});
// testing player data event handler.
mStreamPlayerView.registerDataEventListener("onMetaData", new WOWZDataEvent.EventListener(){
#Override
public WOWZDataMap onWZDataEvent(String eventName, WOWZDataMap eventParams) {
String meta = "";
if(eventParams!=null)
meta = eventParams.toString();
WOWZLog.debug("onWZDataEvent -> eventName "+eventName+" = "+meta);
return null;
}
});
// testing player data event handler.
mStreamPlayerView.registerDataEventListener("onStatus", new WOWZDataEvent.EventListener(){
#Override
public WOWZDataMap onWZDataEvent(String eventName, WOWZDataMap eventParams) {
if(eventParams!=null)
WOWZLog.debug("onWZDataEvent -> eventName "+eventName+" = "+eventParams.toString());
return null;
}
});
// testing player data event handler.
mStreamPlayerView.registerDataEventListener("onTextData", new WOWZDataEvent.EventListener(){
#Override
public WOWZDataMap onWZDataEvent(String eventName, WOWZDataMap eventParams) {
if(eventParams!=null)
WOWZLog.debug("onWZDataEvent -> "+eventName+" = "+eventParams.get("text"));
return null;
}
});
} else {
mHelp.setVisibility(View.GONE);
mStatusView.setErrorMessage(WowzaGoCoder.getLastError().getErrorDescription());
}
}
#Override
protected void onDestroy() {
if (mVolumeSettingChangeObserver != null)
getApplicationContext().getContentResolver().unregisterContentObserver(mVolumeSettingChangeObserver);
super.onDestroy();
}
/**
* Android Activity class methods
*/
#Override
protected void onResume() {
super.onResume();
syncUIControlState();
}
#Override
protected void onPause() {
if (mStreamPlayerView != null && mStreamPlayerView.isPlaying()) {
mStreamPlayerView.stop();
// Wait for the streaming player to disconnect and shutdown...
mStreamPlayerView.getCurrentStatus().waitForState(WOWZState.IDLE);
}
super.onPause();
}
private boolean isNetworkAvailable() {
ConnectivityManager connectivityManager
= (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
return activeNetworkInfo != null && activeNetworkInfo.isConnected();
}
public boolean isPlayerConfigReady()
{
return false;
}
/*
Click handler for network pausing
*/
public void onPauseNetwork(View v)
{
Button btn = (Button)findViewById(R.id.pause_network);
if(btn.getText().toString().trim().equalsIgnoreCase("pause network")) {
WOWZLog.info("Pausing network...");
btn.setText("Unpause Network");
mStreamPlayerView.pauseNetworkStack();
}
else{
WOWZLog.info("Unpausing network... btn.getText(): "+btn.getText());
btn.setText("Pause Network");
mStreamPlayerView.unpauseNetworkStack();
}
}
/**
* Click handler for the playback button
*/
public void onTogglePlayStream(View v) {
if (mStreamPlayerView.isPlaying()) {
mStreamPlayerView.stop();
} else if (mStreamPlayerView.isReadyToPlay()) {
if(!this.isNetworkAvailable()){
displayErrorDialog("No internet connection, please try again later.");
return;
}
// if(!this.isPlayerConfigReady()){
// displayErrorDialog("Please be sure to include a host, stream, and application to playback a stream.");
// return;
// }
mHelp.setVisibility(View.GONE);
WOWZStreamingError configValidationError = mStreamPlayerConfig.validateForPlayback();
if (configValidationError != null) {
mStatusView.setErrorMessage(configValidationError.getErrorDescription());
} else {
// Set the detail level for network logging output
mStreamPlayerView.setLogLevel(mWZNetworkLogLevel);
// Set the player's pre-buffer duration as stored in the app prefs
float preBufferDuration = GoCoderSDKPrefs.getPreBufferDuration(PreferenceManager.getDefaultSharedPreferences(this));
mStreamPlayerConfig.setPreRollBufferDuration(preBufferDuration);
// Start playback of the live stream
mStreamPlayerView.play(mStreamPlayerConfig, this);
}
}
}
/**
* WOWZStatusCallback interface methods
*/
#Override
public synchronized void onWZStatus(WOWZStatus status) {
final WOWZStatus playerStatus = new WOWZStatus(status);
new Handler(Looper.getMainLooper()).post(new Runnable() {
#Override
public void run() {
WOWZStatus status = new WOWZStatus(playerStatus.getState());
switch(playerStatus.getState()) {
case WOWZPlayerView.STATE_PLAYING:
// Keep the screen on while we are playing back the stream
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
if (mStreamPlayerConfig.getPreRollBufferDuration() == 0f) {
mTimerView.startTimer();
}
// Since we have successfully opened up the server connection, store the connection info for auto complete
GoCoderSDKPrefs.storeHostConfig(PreferenceManager.getDefaultSharedPreferences(PlayerActivity.this), mStreamPlayerConfig);
// Log the stream metadata
WOWZLog.debug(TAG, "Stream metadata:\n" + mStreamPlayerView.getMetadata());
break;
case WOWZPlayerView.STATE_READY_TO_PLAY:
// Clear the "keep screen on" flag
WOWZLog.debug(TAG, "STATE_READY_TO_PLAY player activity status!");
if(playerStatus.getLastError()!=null)
displayErrorDialog(playerStatus.getLastError());
playerStatus.clearLastError();
getWindow().clearFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
mTimerView.stopTimer();
break;
case WOWZPlayerView.STATE_PREBUFFERING_STARTED:
WOWZLog.debug(TAG, "Dialog for buffering should show...");
showBuffering();
break;
case WOWZPlayerView.STATE_PREBUFFERING_ENDED:
WOWZLog.debug(TAG, "Dialog for buffering should stop...");
hideBuffering();
// Make sure player wasn't signaled to shutdown
if (mStreamPlayerView.isPlaying()) {
mTimerView.startTimer();
}
break;
default:
break;
}
syncUIControlState();
}
});
}
#Override
public synchronized void onWZError(final WOWZStatus playerStatus) {
new Handler(Looper.getMainLooper()).post(new Runnable() {
#Override
public void run() {
displayErrorDialog(playerStatus.getLastError());
syncUIControlState();
}
});
}
public void onToggleMute(View v) {
mBtnMic.toggleState();
if (mStreamPlayerView != null)
mStreamPlayerView.mute(!mBtnMic.isOn());
mSeekVolume.setEnabled(mBtnMic.isOn());
}
public void onToggleScaleMode(View v) {
int newScaleMode = mStreamPlayerView.getScaleMode() == WOWZMediaConfig.RESIZE_TO_ASPECT ? WOWZMediaConfig.FILL_VIEW : WOWZMediaConfig.RESIZE_TO_ASPECT;
mBtnScale.setState(newScaleMode == WOWZMediaConfig.FILL_VIEW);
mStreamPlayerView.setScaleMode(newScaleMode);
}
public void onStreamMetadata(View v) {
WOWZDataMap streamMetadata = mStreamPlayerView.getMetadata();
WOWZDataMap streamStats = mStreamPlayerView.getStreamStats();
// WOWZDataMap streamConfig = mStreamPlayerView.getStreamConfig().toDataMap();
WOWZDataMap streamConfig = new WOWZDataMap();
WOWZDataMap streamInfo = new WOWZDataMap();
streamInfo.put("- Stream Statistics -", streamStats);
streamInfo.put("- Stream Metadata -", streamMetadata);
//streamInfo.put("- Stream Configuration -", streamConfig);
DataTableFragment dataTableFragment = DataTableFragment.newInstance("Stream Information", streamInfo, false, false);
getFragmentManager().beginTransaction()
.add(android.R.id.content, dataTableFragment)
.addToBackStack("metadata_fragment")
.commit();
}
public void onSettings(View v) {
// Display the prefs fragment
GoCoderSDKPrefs.PrefsFragment prefsFragment = new GoCoderSDKPrefs.PrefsFragment();
prefsFragment.setFixedSource(true);
prefsFragment.setForPlayback(true);
getFragmentManager().beginTransaction()
.replace(android.R.id.content, prefsFragment)
.addToBackStack(null)
.commit();
}
private void syncUIControlState() {
boolean disableControls = (!(mStreamPlayerView.isReadyToPlay() || mStreamPlayerView.isPlaying()) || sGoCoderSDK == null);
if (disableControls) {
mBtnPlayStream.setEnabled(false);
mBtnSettings.setEnabled(false);
mSeekVolume.setEnabled(false);
mBtnScale.setEnabled(false);
mBtnMic.setEnabled(false);
mStreamMetadata.setEnabled(false);
} else {
mBtnPlayStream.setState(mStreamPlayerView.isPlaying());
mBtnPlayStream.setEnabled(true);
if (mStreamPlayerConfig.isAudioEnabled()) {
mBtnMic.setVisibility(View.VISIBLE);
mBtnMic.setEnabled(true);
mSeekVolume.setVisibility(View.VISIBLE);
mSeekVolume.setEnabled(mBtnMic.isOn());
mSeekVolume.setProgress(mStreamPlayerView.getVolume());
} else {
mSeekVolume.setVisibility(View.GONE);
mBtnMic.setVisibility(View.GONE);
}
mBtnScale.setVisibility(View.VISIBLE);
mBtnScale.setVisibility(mStreamPlayerView.isPlaying() && mStreamPlayerConfig.isVideoEnabled() ? View.VISIBLE : View.GONE);
mBtnScale.setEnabled(mStreamPlayerView.isPlaying() && mStreamPlayerConfig.isVideoEnabled());
mBtnSettings.setEnabled(!mStreamPlayerView.isPlaying());
mBtnSettings.setVisibility(mStreamPlayerView.isPlaying() ? View.GONE : View.VISIBLE);
mStreamMetadata.setEnabled(mStreamPlayerView.isPlaying());
mStreamMetadata.setVisibility(mStreamPlayerView.isPlaying() ? View.VISIBLE : View.GONE);
}
}
private void showBuffering() {
try {
if (mBufferingDialog == null) return;
mBufferingDialog.show();
}
catch(Exception ex){}
}
private void cancelBuffering(DialogInterface dialogInterface) {
if(mStreamPlayerConfig.getHLSBackupURL()!=null || mStreamPlayerConfig.isHLSEnabled()){
mStreamPlayerView.stop(true);
}
else if (mStreamPlayerView != null && mStreamPlayerView.isPlaying()) {
mStreamPlayerView.stop(true);
}
}
private void hideBuffering() {
if (mBufferingDialog.isShowing())
mBufferingDialog.dismiss();
}
#Override
public void syncPreferences() {
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
mWZNetworkLogLevel = Integer.valueOf(prefs.getString("wz_debug_net_log_level", String.valueOf(WOWZLog.LOG_LEVEL_DEBUG)));
mStreamPlayerConfig.setIsPlayback(true);
if (mStreamPlayerConfig != null)
GoCoderSDKPrefs.updateConfigFromPrefsForPlayer(prefs, mStreamPlayerConfig);
}
private class StatusCallback implements WOWZStatusCallback {
#Override
public void onWZStatus(WOWZStatus wzStatus) {
}
#Override
public void onWZError(WOWZStatus wzStatus) {
}
}
}
The error I get is;
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.wowza.gocoder.sdk.sampleapp/com.wowza.gocoder.sdk.sampleapp.PlayerActivity}: java.lang.RuntimeException: Invalid surface: null

You start the stream in onCreate. At this time the Surface used by WOWZPlayerView is not ready yet and the app crashes with the 'Invalid surface' error.
If you look at the sample test in the GoCoder SDK, the playback is started when the user clicks a button. Eg. when the Surface is valid.
Create a button and move your 'mStreamPlayerView.play(mStreamPlayerConfig, statusCallback);' to the button.onClick.
Or ... use any GoCoder SDK v1.7 and more recent.
Please, let me know if I can help any further.
Thanks

Attempt to get length of null array on PageFragment

I have this app that shows a help with com.cleveroad.slidingtutorial library
I follow the documentation accord to android.app.Fragment
But I stuck with this error always when close or slide screen to the next pagefragment. I tried with 1 page and more and always get the same error Attempt to get length of null array
Version of slidingtutorial on gradle com.cleveroad:slidingtutorial:1.0.8
Sliding tutorial guide Cleveroad/SlidingTutorial-Android
MainActivityTutorialCrearContacto class
public class MainActivityTutorialCrearContacto extends Activity {
public UsuarioDao usuario;
public Typeface typeface_bold, typeface_regular;
private int[] mPagesColors;
private static final int TOTAL_PAGES = 1;
private static final int ACTUAL_PAGES_COUNT = 3;
private final String TAG = MainActivityTutorialCrearContacto.class.getSimpleName();
public static void start(Context context) {
context.startActivity(new Intent(context, MainActivityTutorialCrearContacto.class));
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_tutorial);
Context ctx = getApplicationContext();
try {
typeface_regular = Typeface.createFromAsset(ctx.getAssets(), Constantes.TYPEFACE_FONT_OPENSANS_REGULAR);
typeface_bold = Typeface.createFromAsset(ctx.getAssets(), Constantes.TYPEFACE_FONT_OPENSANS_SEMIBOLD);
} catch (Exception e) {
e.printStackTrace();
}
mPagesColors = new int[]{
getResources().getColor(R.color.color_fondo_green_dark)
// ,getResources().getColor(R.color.colorPrimaryDark)
// ,getResources().getColor(R.color.color_fondo_orange_pido )
};
if (savedInstanceState == null) {
replaceTutorialFragment();
}
}
final TutorialPageProvider<Fragment> tutorialPageProvider = new TutorialPageProvider<Fragment>() {
#NonNull
#Override
public Fragment providePage(int position) {
switch (position) {
case 0: {
return new ContactoFirstragment();
}
case 1: {
return new ContactoFirstragment();
}
case 2: {
return new ContactoThirdFragment();
}
default: {
throw new IllegalArgumentException("Unknown position: " + position);
}
}
}
};
public void replaceTutorialFragment() {
try {
final IndicatorOptions indicatorOptions = IndicatorOptions.newBuilder(this)
.build();
final TutorialOptions tutorialOptions = TutorialFragment.newTutorialOptionsBuilder(this)
.setUseAutoRemoveTutorialFragment(false)
.setUseInfiniteScroll(false)
.setPagesColors(mPagesColors)
.setPagesCount(TOTAL_PAGES)
.setIndicatorOptions(indicatorOptions)
.setTutorialPageProvider(tutorialPageProvider)
.setOnSkipClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Util.guardarPreferencia(Constantes.VERTUTORIAL_CONTACTO, "ENTENDIDO", getApplicationContext());
try {
//getFragmentManager().popBackStack(); // THIS DON'T CLOSE DE ACTIVITY
finish();
// cierraFragmentTransaction();
} catch (Exception e) {
e.printStackTrace();
}
}
})
.build();
final TutorialFragment tutorialFragment = TutorialFragment.newInstance(tutorialOptions);
getFragmentManager()
.beginTransaction()
.replace(R.id.container, tutorialFragment)
.commit();
} catch (Exception e) {
e.printStackTrace();
}
}
PageFragment Class
class ContactoSecondFragment extends PageFragment {
TextView tv_hola, textView_solicitaremail, textView2, textView1;
public UsuarioDao usuario;
DatabaseManager manager;
public Typeface typeface_bold, typeface_regular;
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Context ctx = getContext();
try {
typeface_regular = Typeface.createFromAsset(ctx.getAssets(), Constantes.TYPEFACE_FONT_OPENSANS_REGULAR);
typeface_bold = Typeface.createFromAsset(ctx.getAssets(), Constantes.TYPEFACE_FONT_OPENSANS_SEMIBOLD);
} catch (Exception e) {
e.printStackTrace();
}
}
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.contacto_fragment_page_second, container, false);
findViews(view);
try {
if(typeface_bold!=null && typeface_regular!=null) {
tv_hola.setTypeface(typeface_bold);
textView1.setTypeface(typeface_regular);
textView2.setTypeface(typeface_regular);
textView_solicitaremail.setTypeface(typeface_regular);
}
checkDatabaseManager();
UsuarioDao usuario = manager.obtenerUsuario();
String nombre = WordUtils.capitalize(usuario.getNombre().toLowerCase());
tv_hola.setText("Hola " + nombre + "\n ¡Vamos a ayudarte!");
} catch (Exception e) {
tv_hola.setText("Hola ¡Vamos a ayudarte!");
}
return view;
}
private void findViews(View view) {
tv_hola = (TextView) view.findViewById(R.id.textView0_hola);
textView1 = (TextView) view.findViewById(R.id.textView1);
textView2 = (TextView) view.findViewById(R.id.textView2);
textView_solicitaremail = (TextView) view.findViewById(R.id.textView_solicitaremail);
}
#Override
protected int getLayoutResId() {
return R.layout.contacto_fragment_page_second;
}
#NonNull
#Override
protected TransformItem[] getTransformItems() {
return new TransformItem[]{
TransformItem.create(R.id.textView0_hola, Direction.RIGHT_TO_LEFT, 0.2f),
TransformItem.create(R.id.img_hola, Direction.LEFT_TO_RIGHT, 0.6f),
TransformItem.create(R.id.textView1, Direction.RIGHT_TO_LEFT, 0.8f),
TransformItem.create(R.id.textView2, Direction.LEFT_TO_RIGHT, 0.10f),
TransformItem.create(R.id.img_email, Direction.RIGHT_TO_LEFT, 0.3f),
TransformItem.create(R.id.textView_solicitaremail, Direction.LEFT_TO_RIGHT, 0.9f)
};
}
private void checkDatabaseManager() {
try {
if (manager == null) {
DatabaseManager.init(getContext());
manager = DatabaseManager.getInstance();
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
Error
Attempt to get length of null array
java.lang.NullPointerException: Attempt to get length of null array
at com.cleveroad.slidingtutorial.PageImpl.onDestroyView(PageImpl.java:71)
at com.cleveroad.slidingtutorial.PageFragment.onDestroyView(PageFragment.java:73)
at android.app.Fragment.performDestroyView(Fragment.java:2570)
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1061)
at android.app.FragmentManagerImpl.detachFragment(FragmentManager.java:1351)
at android.app.BackStackRecord.run(BackStackRecord.java:798)
at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1580)
at android.app.FragmentManagerImpl$1.run(FragmentManager.java:483)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6123)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:757)

Adapter Can't Load Image from JSON on Android

i have some problem with my JSON code.
I want to display a list that contain text and image. The text and image stored on my online database, i using JSON for taking them down to my android app.
The JSON doesn't display any error, the text are displayed but the image are not appear.
I check the logcat and there's no error for this process. I using viewAdapter for displaying the image on the list.
Please master help me, can you gimme some simple explanation how to solve this??
Thanks...
NB. This is my code for HomeFragment.java (where i doing the JSON).
public class HomeFragment extends Fragment implements InternetConnectionListener, ApiHandler.ApiHandlerListener {
private static final String ARG_SECTION_NUMBER = "section_number";
private final int CATEGORY_ACTION = 1;
private CategorySelectionCallbacks mCallbacks;
private ArrayList<Category> categoryList;
private ListView categoryListView;
private String Error = null;
private InternetConnectionListener internetConnectionListener;
public HomeFragment() {
}
public static HomeFragment newInstance(int sectionNumber) {
HomeFragment fragment = new HomeFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
((HomeActivity) activity).onSectionAttached(getArguments().getInt(ARG_SECTION_NUMBER));
try {
mCallbacks = (CategorySelectionCallbacks) activity;
} catch (ClassCastException e) {
throw new ClassCastException("Activity must implement CategorySelectionCallbacks.");
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_home, container, false);
categoryListView = (ListView) rootView.findViewById(R.id.categoryListView);
return rootView;
}
#Override
public void onResume() {
super.onResume();
if (UtilMethods.isConnectedToInternet(getActivity())) {
initCategoryList();
} else {
internetConnectionListener = (InternetConnectionListener) HomeFragment.this;
showNoInternetDialog(getActivity(), internetConnectionListener,
getResources().getString(R.string.no_internet),
getResources().getString(R.string.no_internet_text),
getResources().getString(R.string.retry_string),
getResources().getString(R.string.exit_string), CATEGORY_ACTION);
}
}
public class getCategList extends AsyncTask<Void, Void, Void>{
#Override
protected Void doInBackground(Void... params) {
/**
* json is populating from text file. To make api call use ApiHandler class
*
* <CODE>ApiHandler apiHandler = new ApiHandler(this, URL_GET_CATEGORY);</CODE> <BR>
* <CODE>apiHandler.doApiRequest(ApiHandler.REQUEST_GET);</CODE> <BR>
*
* You will get the response in onSuccessResponse(String tag, String jsonString) method
* if successful api call has done. Do the parsing as the following.
*/
URL hp = null;
try {
hp = new URL(
getString(R.string.liveurl) + "foodcategory.php");
Log.d("URL", "" + hp);
URLConnection hpCon = hp.openConnection();
hpCon.connect();
InputStream input = hpCon.getInputStream();
BufferedReader r = new BufferedReader(new InputStreamReader(input));
String x = "";
x = r.readLine();
String total = "";
while (x != null) {
total += x;
x = r.readLine();
}
Log.d("UR1L", "" + total);
JSONArray j = new JSONArray(total);
Log.d("URL1", "" + j.length());
categoryList = new ArrayList<Category>();
for (int i = 0; i < j.length(); i++) {
Category category = new Category();// buat variabel category
JSONObject Obj;
Obj = j.getJSONObject(i); //sama sperti yang lama, cman ini lebih mempersingkat karena getJSONObject cm d tulis sekali aja disini
category.setId(Obj.getString(JF_ID));
category.setTitle(Obj.getString(JF_TITLE));
category.setIconUrl(Obj.getString(JF_ICON));
if (!TextUtils.isEmpty(Obj.getString(JF_BACKGROUND_IMAGE))) {
category.setImageUrl(Obj.getString(JF_BACKGROUND_IMAGE));
}
Log.d("URL1",""+Obj.getString(JF_TITLE));
categoryList.add(category);
}
getActivity().runOnUiThread(new Runnable() {
#Override
public void run() {
categoryListView.setAdapter(new CategoryAdapter(getActivity(), mCallbacks, categoryList));
}
});
}catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Error = e.getMessage();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Error = e.getMessage();
} catch (JSONException e) {
// TODO Auto-generated catch block
Error = e.getMessage();
e.printStackTrace();
} catch (NullPointerException e) {
// TODO: handle exception
Error = e.getMessage();
}
return null;
}
}
//! function for populate category list
private void initCategoryList() {
new getCategList().execute();
}
#Override
public void onConnectionEstablished(int code) {
if (code == CATEGORY_ACTION) {
initCategoryList();
}
}
#Override
public void onUserCanceled(int code) {
if (code == CATEGORY_ACTION) {
getActivity().finish();
}
}
//! catch json response from here
#Override
public void onSuccessResponse(String tag, String jsonString) {
//! do same parsing as done in initCategoryList()
}
//! detect response error here
#Override
public void onFailureResponse(String tag) {
}
//! callback interface listen by HomeActivity to detect user click on category
public static interface CategorySelectionCallbacks {
void onCategorySelected(String catID, String title);
}
}
This code for categoryAdapter.java (where i put the result of JSON to the list)
public class CategoryAdapter extends ArrayAdapter<Category> implements View.OnClickListener {
private final LayoutInflater inflater;
private final ArrayList<Category> categoryList;
private Activity activity;
private HomeFragment.CategorySelectionCallbacks mCallbacks;
private String dummyUrl = "http://www.howiwork.org";
AbsListView.LayoutParams params;
public CategoryAdapter(Activity activity, HomeFragment.CategorySelectionCallbacks mCallbacks, ArrayList<Category> categoryList) {
super(activity, R.layout.layout_category_list);
this.activity = activity;
this.inflater = LayoutInflater.from(activity.getApplicationContext());
this.categoryList = categoryList;
this.mCallbacks = mCallbacks;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder row;
if (convertView == null) {
convertView = inflater.inflate(R.layout.layout_category_list, null);
row = new ViewHolder();
row.bannerImage = (ImageView) convertView.findViewById(R.id.catBannerImageView);
row.categoryImage = (ImageView) convertView.findViewById(R.id.catImageView);
row.categoryName = (TextView) convertView.findViewById(R.id.catNameTV);
} else {
row = (ViewHolder) convertView.getTag();
}
Category category = categoryList.get(position);
Picasso.with(activity).load(UtilMethods
.getDrawableFromFileName(activity,category.getIconUrl()))
.tag(category.getIconUrl())
.into(row.categoryImage);
row.categoryName.setText(category.getTitle());
Picasso.with(activity)
.load(UtilMethods.getDrawableFromFileName(activity,category.getImageUrl()))
.placeholder(R.drawable.img_banner_placeholder)
.tag(category.getIconUrl())
.fit()
.into(row.bannerImage);
row.bannerImage.setOnClickListener(this);
row.categoryImage.setTag(position);
row.categoryName.setTag(position);
row.bannerImage.setTag(position);
return convertView;
}
#Override
public int getCount() {
return categoryList.size();
}
#Override
public void onClick(View v) {
int position = Integer.parseInt(v.getTag().toString());
mCallbacks.onCategorySelected(categoryList.get(position).getId(),
categoryList.get(position).getTitle());
}
private static class ViewHolder {
public ImageView bannerImage;
public TextView categoryName;
public ImageView categoryImage;
}
}

Try this.
Picasso.with(activity).load(category.getIconUrl())
.into(row.categoryImage);
If it worked !. You Check the UtilMethods.getDrawableFromFileName() !!!

FragmentPagerAdapter dynamic tabs and page count

My application pulls data from a web service that generates different sections for each user. Then I am going to use these sections to create tabs using FragmentPagerAdapter.
I have used an Async task to pull data from the web service. However the overridden methods such as getCount() and getPageTitle() in the FragmentPagerAdapter executed prior to my asynctask and completes its job. How can I prevent this and generate dynamic number of tabs and their title name based on the data fetched from the web service?
In other words how can I create dynamic number of tabs and titles based on the data fetch from the web service
My Code for FragmentPagerAdapter as below. As you can see I have hard coded the amount of tabs as well as their title names.
public class SectionsPagerAdapter extends FragmentPagerAdapter{
private boolean proceedStatus = false;
private String requestURL = "xxxxxxxxxxxxxxxxxxxxxxxx";
//list of fragments need to be added dynamically
public final ArrayList<Fragment> screens = new ArrayList<Fragment>();
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
// Return a DummySectionFragment (defined as a static inner class
// below) with the page number as its lone argument.
Fragment fragment = new SectionFragment();
Bundle args = new Bundle();
args.putInt(SectionFragment.ARG_SECTION_NUMBER, position + 1);
fragment.setArguments(args);
return fragment;
}
#Override
public int getCount() {
return 2;
}
#Override
public CharSequence getPageTitle(int position) {
Locale l = Locale.getDefault();
switch (position) {
case 0:
return "Camera".toUpperCase(l);
case 1:
return getString(R.string.title_section2).toUpperCase(l);
case 2:
return getString(R.string.title_section3).toUpperCase(l);
case 3:
return "SECTION 4";
}
return null;
}
//setting the section title
private void setSectionTitle(){
}
//count the number of sections
private int countNumberofSections(){
int numberOfSection = 0;
return numberOfSection;
}
}
Then I have my Fragment code as below which has the the caller to the Async Task
public static class SectionFragment extends Fragment implements OnTaskCompleted {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private Slider adapter;
private ViewPager viewPager;
public static final String ARG_SECTION_NUMBER = "section_number";
Button thumbUpBut;
Button thumbDownBut;
Button captureButton;
ImageView genImage;
TextView genCaption;
private Camera mCamera;
private CameraPreview mPreview;
private static File mediaFile;
private ProgressDialog progress;
private static String imageSaveLocation;
private static String file_name_without_extension;
private ImageView imageView;
private Button uploadButton;
private Button cancelButton;
private Collection<Place> places = null;
private Collection<Happenings> events = null;
private Collection<General> general = null;
private ArrayList<String> sections;
public int getNumberOfPages(){
return sections.size();
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main_dummy,container, false);
TextView dummyTextView = (TextView) rootView.findViewById(R.id.section_label);
dummyTextView.setText(Integer.toString(getArguments().getInt(ARG_SECTION_NUMBER)));
FeedRequest task = new FeedRequest(this);
task.execute("xxxxxxxxxxxxxxxxxxxxxxxxxxxxx");
captureButton = (Button) rootView.findViewById(R.id.button_capture);
captureButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
takePhoto();
}
});
thumbUpBut = (Button) rootView.findViewById(R.id.thumbUp);
thumbUpBut.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Log.v("thumbPress", "thumbPressUp");
thumb("up");
}
});
thumbDownBut = (Button) rootView.findViewById(R.id.thumbDown);
thumbDownBut.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Log.v("thumbPress", "thumbPressDown");
thumb("down");
}
});
//allocating the activity one to the camera
if(getArguments().getInt(ARG_SECTION_NUMBER) == 1){
mCamera = getCameraInstance();
mPreview = new CameraPreview(this.getActivity(), mCamera);
FrameLayout preview = (FrameLayout)rootView.findViewById(R.id.camera_preview);
preview.addView(mPreview);
//hide buttons
thumbDownBut.setVisibility(rootView.INVISIBLE);
thumbUpBut.setVisibility(rootView.INVISIBLE);
}else{
thumbDownBut.setVisibility(rootView.VISIBLE);
thumbUpBut.setVisibility(rootView.VISIBLE);
captureButton.setVisibility(rootView.INVISIBLE);
}
viewPager = (ViewPager) rootView.findViewById(R.id.pager);
return rootView;
}
//take photo function
private void takePhoto() {
//get coordinates of the location
UserLocation userLocation = new UserLocation();
userLocation.getUserLocation(getActivity());
coordinates[0] = userLocation.longitude;
coordinates[1] = userLocation.latitude;
PictureCallback pictureCB = new PictureCallback() {
public void onPictureTaken(byte[] data, Camera cam) {
new SavePhotoAndMetadata().execute(data);
cam.startPreview();
}
};
mCamera.takePicture(null, null, pictureCB);
}
//get camera instance
private Camera getCameraInstance() {
Camera camera = null;
try {
camera = Camera.open();
} catch (Exception e) {
// cannot get camera or does not exist
}
return camera;
}
//get the media out
private static File getOutputMediaFile() {
File mediaStorageDir = new File(Environment.getExternalStorageDirectory() + "/Android/data/asia.ceynet.realsnap/temp_img");
if (!mediaStorageDir.exists()) {
if (!mediaStorageDir.mkdirs()) {
Log.d("MyCameraApp", "failed to create directory");
return null;
}
}
// Create a media file name
String timeStamp = (DateFormat.format("dd-MM-yyyy hh:mm:ss", new java.util.Date()).toString());
mediaFile = new File(mediaStorageDir.getPath() + File.separator + "IMG_" + timeStamp + ".jpg");
file_name_without_extension = "IMG_" + timeStamp;
imageSaveLocation = mediaFile.toString();
return mediaFile;
}
//saving the image and metadata together
class SavePhotoAndMetadata extends AsyncTask<byte[], String, String> {
#Override
protected String doInBackground(byte[]... data) {
File picFile = getOutputMediaFile();
if (picFile == null) {
return null;
}
byte[] photoData = data[0];
try {
//save the image
FileOutputStream fos = new FileOutputStream(picFile);
fos.write(photoData);
fos.close();
} catch (FileNotFoundException e) {
e.getStackTrace();
} catch (IOException e) {
e.getStackTrace();
}
return null;
}
#Override
protected void onPreExecute() {
super.onPreExecute();
progress = new ProgressDialog(getActivity());
progress.setMessage("Saving Picture..Please wait...");
progress.show();
}
#Override
protected void onPostExecute(String s) {
progress.dismiss();
imagePreviewDialog();
}
}
//save image metadata in async task
class SaveMetadataTask extends AsyncTask<Void, String, Void> {
#Override
protected Void doInBackground(Void... params) {
serializeDeserialize.serializeData("This is for testing", file_name_without_extension, Double.toString(coordinates[0]), Double.toString(coordinates[1]), deviceId, deviceEmail);
return null;
}
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected void onPostExecute(Void v) {
}
}
//image preview dialog and its functionality
private void imagePreviewDialog(){
//setting the bitmap
Bitmap bmp = BitmapFactory.decodeFile(mediaFile.toString());
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
builder.setTitle("Image Preview");
builder.setCancelable(false);
LayoutInflater inflater = getActivity().getLayoutInflater();
ViewGroup vg = (ViewGroup)inflater.inflate(R.layout.sanp_preview_layout, null);
ImageView image = (ImageView) vg.findViewById(R.id.imageView);
image.setImageBitmap(rotateBitmap(bmp));
builder.setView(vg);
//buttons
builder.setPositiveButton("Upload",new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
if(checkInternetConnection.haveNetworkConnection(sContext)){
//upload the image
uploadImage();
//save image metadata
new SaveMetadataTask().execute();
}else{
Toast.makeText(sContext, "Error! No internet connection detected. Image will be uploaded on an active internet connection", Toast.LENGTH_LONG).show();
new SaveMetadataTask().execute();
}
}
});
builder.setNegativeButton("Discard",new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
discardImage(mediaFile.toString());
dialog.dismiss();
}
});
builder.show();
}
private Bitmap rotateBitmap(Bitmap image){
int width=image.getHeight();
int height=image.getWidth();
Bitmap srcBitmap=Bitmap.createBitmap(width, height, image.getConfig());
for (int y=width-1;y>=0;y--)
for(int x=0;x<height;x++)
srcBitmap.setPixel(width-y-1, x,image.getPixel(x, y));
return srcBitmap;
}
//device email
private String getDeviceEmail(){
AccountManager accountManager = AccountManager.get(sContext);
Account[] account = accountManager.getAccountsByType("com.google");
//device email
for(Account accLoop : account){
deviceEmail = accLoop.name;
}
return deviceEmail;
}
//upload image to the server
private void uploadImage(){
//save metadata
//call upload service
Intent intent = new Intent(sContext, HttpUploader.class);
Bundle loc = new Bundle();
loc.putDoubleArray("ss", coordinates);
intent.putExtra("url", PHOTO_UPLOAD);
intent.putExtra("paths", mediaFile.toString());
intent.putExtra("deviceid", deviceId);
intent.putExtra("deviceemail", getDeviceEmail());
intent.putExtra("posttext", "This is for testing");
intent.putExtra("filename", file_name_without_extension);
intent.putExtra("geo", loc);
sContext.startService(intent);
Toast.makeText(getActivity(), "Your image is being uploaded", Toast.LENGTH_LONG).show();
}
//discard image when the discard button is pressed
private void discardImage(String imagePath){
File file = new File(imagePath);
try{
file.delete();
}catch(Exception e){
Log.e("IMAGE_DELETION_ERROR", e.toString());
}
}
#Override
public void onTaskCompleted(boolean status, String message) {
// TODO Auto-generated method stub
Log.e("onTaskCompleted", "success" + status);
if (message == "tumb UP success") {
thumbUpBut.setSelected(true);
thumbDownBut.setSelected(false);
Log.e("tumb", "tumb");
} else if (message == "tumb DOWN success") {
thumbDownBut.setSelected(true);
thumbUpBut.setSelected(false);
Log.e("tumb", "tumb");
}
}
//listener for fetching main objects
#Override
public void onFeedCompleted(ArrayList<Posts> postArray, Multimap<String, Object> multiMap) {
// TODO Auto-generated method stub
numberOfPages = postArray.size();
adapter = new Slider(getActivity(), postArray, getContext());
viewPager.setAdapter(adapter);
// displaying selected image first
viewPager.setCurrentItem(postArray.size());
//saving the keyset
Set<String> keys = multiMap.keySet();
sections = new ArrayList<String>();
//sorting the categories and creating the category list
for(String key:keys){
//getting category list
if(!sections.contains(keys)){
sections.add(key);
}
//sorting categories
if(key.equals("Place")){
places.add((Place) multiMap.get(key));
}else if(key.equals("Events")){
events.add((Happenings) multiMap.get(key));
}else if(key.equals("General")){
general.add((General) multiMap.get(key));
}
}
}
//adding the pages to the adaptor dynamically
public void addPagesDynamically(){
}
}
//create the parent directory
private void createParentDiectory(){
File dir = new File(Environment.getExternalStorageDirectory() + "/Android/data/asia.ceynet.realsnap");
if(!(dir.exists() && dir.isDirectory())) {
dir.mkdirs();
}
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle presses on the action bar items
switch (item.getItemId()) {
case R.id.action_post:
openPost();
return true;
case R.id.action_settings:
// openSettings();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
public void openPost() {
/*
Intent i = new Intent(getApplicationContext(), PhotoActivity.class);
startActivity(i);
*/
}
public static void thumb(String type) {
SectionFragment d = new SectionFragment();
PostThumb task = new PostThumb(type, d);
task.execute("xxxxxxxxxxxxxxxxxxxxxxxxxxxx");
}
//broadcast receiver for picture upload
public class MyWebRequestReceiver extends BroadcastReceiver {
public static final String PROCESS_RESPONSE = "asia.ceynet.intent.action.PROCESS_RESPONSE";
#Override
public void onReceive(Context context, Intent intent) {
//String responseString = intent.getStringExtra(HttpUploader.RESPONSE_STRING);
String reponseMessage = intent.getStringExtra(HttpUploader.RESPONSE_MESSAGE);
String responseStatus = intent.getStringExtra(HttpUploader.RESPONSE_STATUS);
String file_to_be_deleted = intent.getStringExtra(HttpUploader.FILE_NAME_WITHOUT_EXTENSION);
Toast.makeText(getApplicationContext(), reponseMessage + " - " + file_to_be_deleted + ".jpg", Toast.LENGTH_LONG).show();
//if uploaded successfully delete or image and metadata
if(responseStatus.equals("true")){
File temp_image_dir = new File(Environment.getExternalStorageDirectory() + "/Android/data/asia.ceynet.realsnap/temp_img/" + file_to_be_deleted + ".jpg");
File metadata_file = new File(Environment.getExternalStorageDirectory() + "/Android/data/asia.ceynet.realsnap/temp_img/" + file_to_be_deleted + ".ser");
try{
temp_image_dir.delete();
metadata_file.delete();
}catch(Exception e){
Log.e("IMAGE_DELETION_ERROR", e.toString());
}
}
}
}

When you finnish pulling the async data, provide the adapter with the new data and call .notifyDataSetChanged() on that adapter instance and the framework will update the pages and count by itself.
If you wish a more detailed explanation post your FragmentPagerAdapter implementation.

First of all, let me apologize if I'm not making myself clear enough because this is one of my first participation(s) here. But I'll be always here to answer queries related to this answer and clear any confusions arose by my statements.
Since you're using fragments, so I'm assuming you must have included your fragments inside an activity (lets say MainActivity.java).
What you need, can be done inside that activity containing fragment.
Here is the example code of onCreate method inside the MainActivity
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
FragmentManager fragmentManager = getSupportFragmentManager();
//Instance of viewpager included inside activity_main.xml
viewPager = (ViewPager) findViewById(R.id.vpMain);
SectionsPagerAdapter adapter = new SectionsPagerAdapter (fragmentManager);
//Adding some fragments right from the beginning, you could ignore it if not needed.
addFragments();
//This `OnPageChangeListener` will do the trick for you.
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
//Show the title of fragment
Toast.makeText(MainActivity.this, adapter.screens.get(position), Toast.LENGTH_SHORT).show();
//If fragment being loaded is later than the first one,
// then add one more fragment after the last fragment to the adapter.
// integer currentPosition is declared as a field, outside onCreate method and initially set to 0.
if(position>currentPosition){
currentPosition+=1;
adapter.addFragment(new SectionFragment(), "Fragment"+String.valueOf(position+3));
adapter.notifyDataSetChanged();
}else{
currentPosition--;
}
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
} // onCreate ends here.
Create this method inside your MainActivity (just to add 3 fragments to give your application a head-start.
private void addFragments(){
adapter.addFragment(new SectionFragment());
adapter.addFragment(new SectionFragment());
adapter.addFragment(new SectionFragment());
}
Then modify your SectionsPagerAdapter's getItem and getCount methods as below:
public class SectionsPagerAdapter extends FragmentPagerAdapter{
private boolean proceedStatus = false;
private String requestURL = "xxxxxxxxxxxxxxxxxxxxxxxx";
//list of fragments need to be added dynamically
public final ArrayList<Fragment> screens = new ArrayList<Fragment>();
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
return screens.get(position);
}
#Override
public int getCount() {
return screens.size();
}
//This method will dynamically add a fragment each time it is called.
public void addFragment(Fragment fragment) {
screens.add(fragment);
}
Now, no work related to "adding new fragment to the list" needs to be done inside your SectionFragment class.