Develop Reference

get TextView from another class

I want to display this textview "txtCalculate" which comes from the class CustomerMapActivity which is displayed in the activity_map_customer layout in another layout which is activity_bon_de_commande, of the class BonDeCommande.
the problem is I don't know how to do it
I'm new to java programming
thank you
public void readValues(){
DatabaseReference ref = FirebaseDatabase.getInstance().getReference();
Query lastQuery = ref.child("ride_info").orderByKey().limitToLast(1);
lastQuery.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot ds : dataSnapshot.getChildren()){
double value0_float = ds.child("pickup").child("lat").getValue(Double.class);
double value1_float = ds.child("pickup").child("lng").getValue(Double.class);
double value2_float = ds.child("destination").child("lat").getValue(Double.class);
double value3_float = ds.child("destination").child("lng").getValue(Double.class);
String pickupLat = String.valueOf(value0_float);
String pickupLng = String.valueOf(value1_float);
String destiLat = String.valueOf(value2_float);
String destiLng = String.valueOf(value3_float);
String requestUrl=null;
try {
requestUrl = "https://maps.googleapis.com/maps/api/directions/json?"+
"mode=driving&"
+"transit_routing_preference=less_driving&"
+"origin="+pickupLat+","+pickupLng+"&"
+"destination="+destiLat+","+destiLng+"&"
+"key="+getResources().getString(R.string.google_maps_key);
Log.e("LINK",requestUrl);
mService.getPath(requestUrl).enqueue(new Callback<String>() {
#Override
public void onResponse(Call<String> call, Response<String> response) {
try {
JSONObject jsonObject = new JSONObject(response.body().toString());
JSONArray routes = jsonObject.getJSONArray("routes");
JSONObject object = routes.getJSONObject(0);
JSONArray legs = object.getJSONArray("legs");
JSONObject legsObject = legs.getJSONObject(0);
//Get distance
JSONObject distance = legsObject.getJSONObject("distance");
String distance_text = distance.getString("text");
//use regex to extract double from string
//This regex will remove all text not digit
Double distance_value= Double.parseDouble(distance_text.replaceAll("[^0-9\\\\.]+",""));
//Get Time
JSONObject time = legsObject.getJSONObject("duration");
String time_text = time.getString("text");
Integer time_value = Integer.parseInt(time_text.replaceAll("\\D+",""));
String final_calculate = String.format("%.2f €",
TypeObject.getPrice(distance_value,time_value));
HERE -----> txtCalculate.setText(final_calculate);
} catch (JSONException e) {
e.printStackTrace();
}
}
#Override
public void onFailure(Call<String> call, Throwable t) {
mCurrentRide.cancelRide();
endRide();
}
});
}
catch (Exception ex)
{
ex.printStackTrace();
}
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
mCurrentRide.cancelRide();
endRide();
}
});
}
screenshot of my screen

You need to Create an Interface with an update method, declare in your Activity and after, pass as parameter to your handler object that gets the data.
Don't forget If you're getting the data in a different Thread, you need to update your views always in an UI Thread or in the Main Thread.
Here Follow some example code:
Your Activity or Fragment
public class MainActivity extends AppCompatActivity
implements UpdateViewCallback { // implement the interface here
private TextView textView = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
textView = findViewById(R.id.textView);
// Pass the interface in your Object that makes the async work
final AsyncWork asyncWork = new AsyncWork(this);
// Running
Thread thread = new Thread(asyncWork);
thread.start();
}
/**
* UpdateViewCallback
* #param result
*/
#Override
public void updateView(final String result) {
// Always update View on MainThread or an UI Thread, or else issues will start to happening
this.runOnUiThread(new Runnable() {
public void run() {
// Check if View is null since you're updating in a thread async
if (textView != null) {
textView.setText(result);
}
}
});
}
}
Your Interface:
public interface UpdateViewCallback {
void updateView(String result);
}
Your Object to handle the Async Work:
public class AsyncWork implements Runnable {
private UpdateViewCallback updateViewCallback;
public AsyncWork(UpdateViewCallback updateViewCallback) {
this.updateViewCallback = updateViewCallback;
}
/**
* Async Work here
*/
#Override
public void run() {
// Do some Work and after update using the interface you passed in the constructor
updateViewCallback.updateView("This is a test");
}
}

What is the easiest way to update a textView from a service?

I am making an app which consists of an activity and a service. By pressing a button the service is started, it collects data in the background from a sensor and classifies it and outputs a string. I want to display the string in a textView. Right now I can see in the log that the variable is updated 2 times every second, but when I try and update the textView from the service class nothing is happening unless I press the button, whenever I press the button, the string is displayed in the textView.
What is the easiest solution here? I tried to make the textView static and it still can't update it. Can you make it so that the view is updated automatically every second? Can I add a listener somehow? Since I am not very experienced I would like an easy solution that does not have to be a "good" one.
Here is my code
Activity:
public class CollectorActivity extends Activity {
private enum State {
IDLE, COLLECTING, TRAINING, CLASSIFYING
};
private final String[] mLabels = { Globals.CLASS_LABEL_STANDING,
Globals.CLASS_LABEL_WALKING, Globals.CLASS_LABEL_RUNNING,
Globals.CLASS_LABEL_OTHER };
private RadioGroup radioGroup;
private final RadioButton[] radioBtns = new RadioButton[4];
private Intent mServiceIntent;
private File mFeatureFile;
public static TextView mCurrentLabel;
private State mState;
private Button btnDelete;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
radioGroup = (RadioGroup) findViewById(R.id.radioGroupLabels);
radioBtns[0] = (RadioButton) findViewById(R.id.radioStanding);
radioBtns[1] = (RadioButton) findViewById(R.id.radioWalking);
radioBtns[2] = (RadioButton) findViewById(R.id.radioRunning);
radioBtns[3] = (RadioButton) findViewById(R.id.radioOther);
btnDelete = (Button) findViewById(R.id.btnDeleteData);
mCurrentLabel = (TextView) findViewById(R.id.textView);
mState = State.IDLE;
mFeatureFile = new File(getExternalFilesDir(null),
Globals.FEATURE_FILE_NAME);
mServiceIntent = new Intent(this, SensorsService.class);
}
public void onCollectClicked(View view) {
if (mState == State.IDLE) {
mState = State.COLLECTING;
((Button) view).setText(R.string.ui_collector_button_stop_title);
btnDelete.setEnabled(false);
radioBtns[0].setEnabled(false);
radioBtns[1].setEnabled(false);
radioBtns[2].setEnabled(false);
radioBtns[3].setEnabled(false);
int acvitivtyId = radioGroup.indexOfChild(findViewById(radioGroup
.getCheckedRadioButtonId()));
String label = mLabels[acvitivtyId];
Bundle extras = new Bundle();
extras.putString(Globals.CLASS_LABEL_KEY, label);
mServiceIntent.putExtras(extras);
startService(mServiceIntent);
} else if (mState == State.COLLECTING) {
mState = State.IDLE;
((Button) view).setText(R.string.ui_collector_button_start_title);
btnDelete.setEnabled(true);
radioBtns[0].setEnabled(true);
radioBtns[1].setEnabled(true);
radioBtns[2].setEnabled(true);
radioBtns[3].setEnabled(true);
stopService(mServiceIntent);
((NotificationManager) getSystemService(NOTIFICATION_SERVICE)).cancelAll();
}
}
public void onDeleteDataClicked(View view) {
if (Environment.MEDIA_MOUNTED.equals(Environment
.getExternalStorageState())) {
if (mFeatureFile.exists()) {
mFeatureFile.delete();
}
Toast.makeText(getApplicationContext(),
R.string.ui_collector_toast_file_deleted,
Toast.LENGTH_SHORT).show();
}
}
#Override
public void onBackPressed() {
if (mState == State.TRAINING) {
return;
} else if (mState == State.COLLECTING || mState == State.CLASSIFYING) {
stopService(mServiceIntent);
((NotificationManager) getSystemService(NOTIFICATION_SERVICE))
.cancel(Globals.NOTIFICATION_ID);
}
super.onBackPressed();
}
#Override
public void onDestroy() {
// Stop the service and the notification.
// Need to check whether the mSensorService is null or not.
if (mState == State.TRAINING) {
return;
} else if (mState == State.COLLECTING || mState == State.CLASSIFYING) {
stopService(mServiceIntent);
((NotificationManager) getSystemService(NOTIFICATION_SERVICE))
.cancelAll();
}
finish();
super.onDestroy();
}
And this is the "doInBackground" method in my service class. The line "CollectorActivity.mCurrentLabel.setText(classification);" is the problem. I want this to update the textView continously.
public class OnSensorChangedTask extends AsyncTask<Void, Void, Void> {
#Override
protected Void doInBackground(Void... arg0) {
Instance inst = new DenseInstance(mFeatLen);
inst.setDataset(mDataset);
Instance inst2 = new DenseInstance(65);
int blockSize = 0;
FFT fft = new FFT(Globals.ACCELEROMETER_BLOCK_CAPACITY);
double[] accBlock = new double[Globals.ACCELEROMETER_BLOCK_CAPACITY];
double[] re = accBlock;
double[] im = new double[Globals.ACCELEROMETER_BLOCK_CAPACITY];
double max = Double.MIN_VALUE;
while (true) {
try {
// need to check if the AsyncTask is cancelled or not in the while loop
if (isCancelled () == true)
{
return null;
}
// Dumping buffer
accBlock[blockSize++] = mAccBuffer.take().doubleValue();
if (blockSize == Globals.ACCELEROMETER_BLOCK_CAPACITY) {
blockSize = 0;
testList = new ArrayList<Double>();
// time = System.currentTimeMillis();
max = .0;
for (double val : accBlock) {
if (max < val) {
max = val;
}
}
fft.fft(re, im);
for (int i = 0; i < re.length; i++) {
double mag = Math.sqrt(re[i] * re[i] + im[i]
* im[i]);
inst.setValue(i, mag);
testList.add(i,mag);
im[i] = .0; // Clear the field
}
// Append max after frequency component
inst.setValue(Globals.ACCELEROMETER_BLOCK_CAPACITY, max);
inst2.setValue(Globals.ACCELEROMETER_BLOCK_CAPACITY, max);
testList.add(max);
classificationIndex = WekaClassifier.classify(testList.toArray());
classification = testLabel.get((int) classificationIndex);
CollectorActivity.mCurrentLabel.setText(classification);
inst.setValue(mClassAttribute, mLabel);
mDataset.add(inst);
Log.i("new instance", mDataset.size() + "");
}
} catch (Exception e) {
e.printStackTrace();
}
}
}

In doInBackground(Void... arg0) change CollectorActivity.mCurrentLabel.setText(classification); to publishProgress(classification); then change second argument from Void to String: public class OnSensorChangedTask extends AsyncTask<Void, Srting, Void> and add onProgressUpdate().
Finally your code should looks like:
public class OnSensorChangedTask extends AsyncTask<Void, Srting, Void> {
#Override
protected Void doInBackground(Void... arg0) {
//...
publishProgress(classification);
//...
}
#Override
protected Void onProgressUpdate(String... classification) {
CollectorActivity.mCurrentLabel.setText(classification[0]);
}

Two-Dimensional Array with JSON data - Data is downloaded, but I can't access it (?)

So, I am creating a little trivia game for learning purposes, but I ran into a problem.
First, I had a specific Android Fragment obtaining the data from JSON, and I will simply use that data on the callback method and display it on TextViews and Buttons. Everything was working fine, however, every time I returned to that fragment, the same questions would be there. So I decided to handle that in a better way outside of the callback method.
The problem here is that apparently my Arrays are either null or their lengths is zero. Which is weird, because according to my LOG, data is being passed to those arrays on the callback method.
Here's my full fragment code. Thanks!
public class GameFragment extends Fragment {
private TextView txtQuestion;
private Button btnAnswer1;
private Button btnAnswer2;
private Button btnAnswer3;
private Button btnAnswer4;
private Questions[] gameQuestions;
private Questions[] animeQuestions;
private Questions[] techQuestions;
private Questions[] movieQuestions;
private Questions[][] gameCategories = new Questions[4][];
int correctAnswer = -1;
private TransparentProgressDialog progressBar;
private Handler handler;
private Runnable runnable;
Callback cb = new Callback<MyApiData>(){
#Override
public void success(MyApiData myApiData, Response response) {
gameCategories[0] = new Questions[myApiData.getCategory()[0].getQuestions(0).length];
gameCategories[1] = new Questions[myApiData.getCategory()[1].getQuestions(1).length];
gameCategories[2] = new Questions[myApiData.getCategory()[2].getQuestions(2).length];
gameCategories[3] = new Questions[myApiData.getCategory()[3].getQuestions(3).length];
//gameCategories = new Questions[][] {gameQuestions, animeQuestions, techQuestions, movieQuestions};
for(int i = 0; i < 4 ; i++){
for(int j = 0; j < gameCategories[i].length ; j++){
gameCategories[i][j] = myApiData.getCategory()[i].getQuestions(i)[j];
//Log.d("GameFragment", "gameCategories[i][j] - gameCategories["+i+"]["+j+"]: " + gameCategories[i][j].getQuestion());
}
}
//displayQuestion();
progressBar.dismiss();
displayQuestion();
}
#Override
public void failure(RetrofitError error) {
Log.d("GameScreen", "Callback failed!");
}
};
public GameFragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_game, container, false);
txtQuestion = (TextView) view.findViewById(R.id.txtQuestion);
btnAnswer1 = (Button) view.findViewById(R.id.btnAnswer1);
btnAnswer2 = (Button) view.findViewById(R.id.btnAnswer2);
btnAnswer3 = (Button) view.findViewById(R.id.btnAnswer3);
btnAnswer4 = (Button) view.findViewById(R.id.btnAnswer4);
btnAnswer1.setOnClickListener(new View.OnClickListener() {
#Override public void onClick(View view) { checkAnswer(view); } });
btnAnswer2.setOnClickListener(new View.OnClickListener() {
#Override public void onClick(View view) { checkAnswer(view); } });
btnAnswer3.setOnClickListener(new View.OnClickListener() {
#Override public void onClick(View view) { checkAnswer(view); } });
btnAnswer4.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
checkAnswer(view);
}
});
handler = new Handler();
progressBar = new TransparentProgressDialog(getActivity(), R.drawable.loading_spinner);
runnable = new Runnable() {
#Override
public void run() {
if (progressBar.isShowing()) {
progressBar.dismiss();
}
}
};
//launchRingDialog();
//RestClient.get().getQuestions(cb);
// Inflate the layout for this fragment
return view;
}
public void launchRingDialog() {
new Thread(new Runnable() {
public void run(){
try {
Log.d("Thred", "Try");
progressBar.show();
RestClient.get().getQuestions(cb);
//Thread.sleep(10000);
} catch (Exception e) {
}
//progressBar.dismiss();
}
}).start();
}
public void checkAnswer(View v){
switch(v.getId()){
case R.id.btnAnswer1:
if(correctAnswer == 1){
feedback(true, btnAnswer1);
}else {
feedback(false, btnAnswer1);
}
break;
case R.id.btnAnswer2:
if(correctAnswer == 2){
feedback(true, btnAnswer2);
}else {
feedback(false, btnAnswer2);
}
break;
case R.id.btnAnswer3:
if(correctAnswer == 3){
feedback(true, btnAnswer3);
}else {
feedback(false, btnAnswer3);
}
break;
case R.id.btnAnswer4:
if(correctAnswer == 4){
feedback(true, btnAnswer4);
}else {
feedback(false, btnAnswer4);
}
break;
default: txtQuestion.setText("Error");
break;
}
}
public void feedback(Boolean correct, Button btn){
if(correct){
btn.setBackgroundColor(Color.GREEN);
btn.setText("CORRECT!");
}else{
btn.setBackgroundColor(Color.RED);
btn.setText("WRONG!");
}
}
#Override
public void onResume() {
super.onResume();
//displayQuestion();
}
public void displayQuestion(){
Random randomizer = new Random();
int randomQuestion;
int category = GTMain.choosenCategory;
if(category == 5){
category = randomizer.nextInt(4);
}
randomQuestion = randomizer.nextInt(25);
Log.d("displayQuestion", "Before if statements");
if(gameCategories != null && gameCategories.length != 0) {
Log.d("displayQuestion", "First if");
if(gameCategories[category] != null && gameCategories[category].length != 0){
Log.d("displayQuestion", "Second if");
txtQuestion.setText(gameCategories[category][randomQuestion].getQuestion());
correctAnswer = gameCategories[category][randomQuestion].getCorrectAnswer();
Log.d("displayQuestion()", "correctAnswer: " + correctAnswer);
btnAnswer1.setText(gameCategories[category][randomQuestion].getAnswers().getA1());
btnAnswer2.setText(gameCategories[category][randomQuestion].getAnswers().getA2());
btnAnswer3.setText(gameCategories[category][randomQuestion].getAnswers().getA3());
btnAnswer4.setText(gameCategories[category][randomQuestion].getAnswers().getA4());
}
}
}
}
PS: On my main activity, I check to see which fragment should be loaded. If it's the fragment that contains the components to display the questions and answer (the one from the code above), I call the following method: gameFragment.launchRingDialog(); (and yes, I have created an instance of my GameFragment fragment before calling that method!)

When onResume() is called, your RestClient.get().getQuestions(cb) is still running in background, and your call displayQuestion(), so of course nothing is shown.
Can you put displayQuestion() inside success() of your callback?
Callback cb = new Callback<MyApiData>(){
#Override
public void success(MyApiData myApiData, Response response) {
....
for(int i = 0; i < 4 ; i++){
for(int j = 0; j < gameCategories[i].length ; j++){
...
}
}
displayQuestion();
}
....
};
I would also suggest you to remove displayQuestion() in onResume() method.

OnMenuButton not posting data to google spreadsheets

Hey guys i have got this problem for a while now and i cannot figure out as to why it is not working. when i use the code provided by the tutorial that i have followed on YouTube it works fine, which is posting that data as soon as the application starts. However what i am trying to do is post the data as soon as the "Save Register" button is pressed in the menu but the it doesnt work and returns the message as shown in Log Cat.
I am getting the feeling that i am supposed to create an Async task for this however because my android programming is very limited i am not to sure how i would go about creating this.
My Main activity Class:
public class MainActivity extends Activity{
boolean wasApEnabled = false;
static AccessPoint wifiAP;
private WifiManager wifi;
static Button apButton;
static TextView textView;
final String myTag = "DocsUpload";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
apButton = (Button) findViewById(R.id.toggleBtn);
textView = (TextView) findViewById(R.id.wifiClients);
apButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
wifiAP.toggleWifiAP(wifi, MainActivity.this);
}
});
/*Log.i(myTag, "OnCreate()");
Thread t = new Thread(new Runnable() {
#Override
public void run() {
postData();
}
});*/
//t.start();
wifiAP = new AccessPoint(this);
wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
postData();
scan();
//getWindow().addFlags(WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD|WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON|WindowManager.LayoutParams.FLAG_DIM_BEHIND);
}
private void scan(){
wifiAP.getClientList(false, new FinishScanListener() {
#Override
public void onFinishScan(final ArrayList<ClientScanResult> clients) {
textView.setText("WifiApState:" + wifiAP.getWifiApState()+ "\n\n");
textView.append("Clients: \n");
for (ClientScanResult clientScanResult : clients){
textView.append("====================\n");
textView.append("ipAddress: " + clientScanResult.getIpAddress() + "\n");
textView.append("Device: " + clientScanResult.getDevice() + "\n");
textView.append("macAddress: " + clientScanResult.getMacAddress() + "\n");
textView.append("isReachable: " + clientScanResult.isReachable() + "\n");
}
}
});
}
public void postData() {
String fullUrl = "https://docs.google.com/forms/d/1yipuuXd5V53Ol12U24Cl2H4RIdYtm622jIk13Zo26cM/formResponse";
HttpRequest mReq = new HttpRequest();
String col1 = "Hello";
String col2 = "World";
String data = "entry_272641491=" + URLEncoder.encode(col1) + "&" +
"entry_130393492=" + URLEncoder.encode(col2);
String response =mReq.sendPost(fullUrl, data);
// Log.i(myTag, response);
}
#Override
public void onResume() {
super.onResume();
if (wasApEnabled) {
if (wifiAP.getWifiApState() != wifiAP.WIFI_STATE_ENABLED && wifiAP.getWifiApState() != wifiAP.WIFI_STATE_ENABLING) {
wifiAP.toggleWifiAP(wifi, MainActivity.this);
}
}
updateStatusDisplay();
}
#Override
public void onPause() {
super.onPause();
boolean wifiApIsOn = wifiAP.getWifiApState()==wifiAP.WIFI_STATE_ENABLED || wifiAP.getWifiApState()==wifiAP.WIFI_STATE_ENABLING;
if (wifiApIsOn){
wasApEnabled = true;
wifiAP.toggleWifiAP(wifi, MainActivity.this);
}else {
wasApEnabled = false;
}
updateStatusDisplay();
}
public static void updateStatusDisplay(){
if (wifiAP.getWifiApState()==wifiAP.WIFI_STATE_ENABLED || wifiAP.getWifiApState()==wifiAP.WIFI_STATE_ENABLING){
apButton.setText("Turn Off");
}else {
apButton.setText("Turn on");
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
menu.add(0,0,0, "Get Clients");
menu.add(0,1,0, "Save Register");
getMenuInflater().inflate(R.menu.menu_main, menu);
return super.onCreateOptionsMenu(menu);
}
public boolean onMenuItemSelected(int featureId, MenuItem item) {
switch (item.getItemId()){
case 0:
scan();
break;
case 1:
postData();
break;
}
return super.onMenuItemSelected(featureId, item);
}
}
This is the helper class that i have used, Credit goes to this stack overflow user for creating this class
Secure HTTP Post in Android
This is the log cat that i am getting
03-12 15:06:27.428 3096-3096/com.example.gavin.wifiattendance D/Your App Name Here﹕ https://docs.google.com/forms/d/1yipuuXd5V53Ol12U24Cl2H4RIdYtm622jIk13Zo26cM/formResponse?entry_272641491=Hello&entry_130393492=World
03-12 15:06:27.428 3096-3096/com.example.gavin.wifiattendance E/WifiAttendance﹕ HttpUtils: android.os.NetworkOnMainThreadException
03-12 15:06:27.428 3096-3096/com.example.gavin.wifiattendance D/WifiAttendance﹕ Returning value:null

I am getting the feeling that i am supposed to create an Async task
for this
Correct. NetworkOnMainThreadException is thrown when you are trying to make network calls on your Main Thread (UI thread).
You can find a good tutorial on AsyncTask here.
Example from the tutorial:
private class DownloadWebPageTask extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... urls) {
String response = "";
//Do your network calls here
return response;
}
#Override
protected void onPostExecute(String result) {
//When you are done, this method runs on the UI thread so you can update the UI from here
textView.setText(result);
}
}
Finally you execute it like so
DownloadWebPageTask task = new DownloadWebPageTask();
task.execute(new String[] { "http://www.vogella.com" });

Thank you for the #Marcus for the helpful links i managed to get it working using this code:
public class PostDataTask extends AsyncTask<String, Void, Integer>{
#Override
protected Integer doInBackground(String... params) {
HttpRequest mReq = new HttpRequest();
String data = "entry_272641491=" + URLEncoder.encode(params[1]) + "&" +
"entry_130393492=" + URLEncoder.encode(params[2]);
String response = mReq.sendPost(params[0], data);
return 200;
}
}

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.