I'm not that much experienced in Android, so every piece of code I have written so far was very simple. Now I need to implement a localization and navigation application, so I need to break my code into modules so that I can change each component alone. I have some variables that I need to share them between different classes. I used static variables but I read in some posts here that static variables are not preferred. Then I found some other posts talking about Context. So I created a class named Globals and I added the following lines in my Manifest file:
<application android:name="com.example.smartnav.Globals"
package="com.example.smartnav"
android:icon="#drawable/ic_launcher"
android:allowBackup="true"
android:label="#string/app_name"/>
And here is the Globals Class :
package com.example.smartnav;
import java.util.List;
import android.net.wifi.ScanResult;
import android.app.Application;
public class Globals extends Application {
private Boolean Scanning=false;
private String Logname;
private int interval;
private int numOfScans;
private List<ScanResult> result;
//getters
public Boolean getScannig(){
return Scanning;
}
public int getInterval()
{
return interval;
}
public int getScans()
{
return numOfScans;
}
public List<ScanResult> getRes()
{
return result;
}
public String getLog()
{
return Logname;
}
//setter
public void setScanning(Boolean s){
Scanning= s;
}
public void setRes(List<ScanResult> res)
{
result =res;
}
public void setInterval(int I)
{
interval = I;
}
public void setScans(int S)
{
numOfScans=S;
}
public void setLog(String s)
{
Logname= s;
}
}
Now I have two questions, the first one is that my application keeps crashing whenever I try to use the Globals class, here is the code: Did I use context incorrectly?
public class MainActivity extends Activity {
private Context context;
public WifiManager Wifi;
private WifiReceiver receiverWifi;
private IntentFilter filter;
private List<ScanResult> result;
private File AppDir;
private static String filename;
private File file;
private FileWriter writer;
private Globals AppState ;
private int Interval;
private int numOfScans;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Log.d("Main ","activity created");
//
AppState = ((Globals)getApplicationContext());
context= this;
Wifi=(WifiManager) getSystemService(Context.WIFI_SERVICE);
receiverWifi = new WifiReceiver();
filter= new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION);
registerReceiver(receiverWifi, filter);
Log.d("Main ","wifi registered");
// create the application directory
AppDir = new File(Environment.getExternalStorageDirectory()+"/SmartNavi/Log");
if(AppDir.isDirectory())
{
filename=Environment.getExternalStorageDirectory()+"/SmartNavi/Log/log.txt";
file = new File(filename);
if(!file.exists())
try {
file.createNewFile();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
else
{
Date d= new Date();
filename=Environment.getExternalStorageDirectory()+"/SmartNavi/Log/log"+d.getTime()+".txt";
file = new File(filename);
try {
file.createNewFile();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
else
{
AppDir.mkdirs();
filename=Environment.getExternalStorageDirectory()+"/SmartNavi/Log/log.txt";
file = new File(filename);
if(!file.exists())
try {
file.createNewFile();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
else
{
Date d= new Date();
filename=Environment.getExternalStorageDirectory()+"/SmartNavi/Log/log"+d.getTime()+".txt";
file = new File(filename);
try {
file.createNewFile();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
//setting pars
Interval=250;
numOfScans=4;
AppState.setInterval(Interval);
AppState.setScans(numOfScans);
AppState.setLog(filename);
Wifi.startScan();
try {
writer = new FileWriter(file, true);
writer.append("Smart Navigation. \n");
writer.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// AsyncScanning.AsyncScan();
}//on create
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
class WifiReceiver extends BroadcastReceiver {
public void onReceive(Context c, Intent intent) {
result=Wifi.getScanResults();
// AppState.setRes(result);
try {
writer = new FileWriter(file, true);
writer.append(result.size()+" s \n");
writer.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}//end of on receive
}// end of class
} // end of smartNav
My last question is this : I have read on some answers here that if my application becomes a background process then all the data in the context will be set to null, and I will lose my context. Is there is any method to overcome this point? or should I switch to SharedPreferences ?
Edit :Here is the output of Logcat
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.smartnav/com.example.smartnav.MainActivity}: java.lang.ClassCastException: android.app.Application cannot be cast to com.example.smartnav.Globals
Now I have two questions, the first one is that my application keeps crashing whenever I try to use the Globals class, here is the code: Did I use context incorrectly?
you should use getApplication() method for that, or make your application class singleton, so you would call Globals.getInstance().getMyVariable() etc.
My last question is this : I have read on some answers here that if my application becomes a background process then all the data in the context will be set to null, and I will lose my context. Is there is any method to overcome this point? or should I switch to SharedPreferences ?
if your app becomes background then Android is more likely to kill your app, and this way also destroy all your static objects. Inside your Globals class you should not store your data in static variables but rather in some persistant storage - if its small then use SharedPreferences, if its large then you can store it in json and save to application memory, or use sqlite db.
Related
I recently created an activity in my app. Now I wanted the user to download a .pdf file when he/she wants to view the guidelines. I wanted to implement this on a button. Any idea how to do this properly?
Heres my code below:
public class Exhibitor_Registration_Activity extends AppCompatActivity {
Button buttonDownload;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_exhibitor_registration_);
this.setTitle("Buyer Registration");
Toolbar myToolbar = (Toolbar) findViewById(R.id.my_toolbar);
setSupportActionBar(myToolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
myToolbar.setNavigationIcon(R.drawable.ic_arrow_back_white_24dp);
final Button buttonDownload = (Button) findViewById(R.id.buttonDownload);
buttonDownload.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View view) {
try {
//this is the file you want to download from the remote server
String path ="http://www.manilafame.com/website-assets/downloads/exhibitor-application-kit/local/201704/1-Summary-of-Participation-Details-April-2017_MN_002.pdfp";
//this is the name of the local file you will create
String targetFileName = null;
boolean eof = false;
URL u = new URL(path);
HttpURLConnection c = (HttpURLConnection) u.openConnection();
c.setRequestMethod("GET");
c.setDoOutput(true);
c.connect();
FileOutputStream f = new FileOutputStream(new File("c:\\junk\\"+targetFileName));
InputStream in = c.getInputStream();
byte[] buffer = new byte[1024];
int len1 = 0;
while ( (len1 = in.read(buffer)) > 0 ) {
f.write(buffer,0, len1);
}
f.close();
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
}
}
I also got the source code from here and here.
if you want resumable, speed of download ...
follow this steps
create a class DownloadManager.java
public class DownloadManager extends AsyncTask<String,String,String>{
String downloadlink,fileDestination;
public static final int ON_INIT=100,ON_ERROR=102,ON_PROGRASS=103,ON_COMPLETED=104,STATUS_DOWNLOADED=1500,STATUS_NOT_YET=1501;
private onUpdateListener onUpdateListener;
private String downloadedPath="";
private long downloaded=0;
private File file;
private String returnData=null;
private File cacheDownloadFile;
public DownloadManager(String downloadlink,String fileDestinationPath){
this.downloadlink=downloadlink;
this.fileDestination=fileDestinationPath;
file=new File(fileDestination, Tools.getFileName(downloadlink));
cacheDownloadFile=new File(AppCostants.CHACHE_PATH+Tools.getFileName(downloadlink));
try {
if(cacheDownloadFile.isFile())
downloaded=Tools.getFileSize(cacheDownloadFile);
else
downloaded=0;
Log.d("FILE_DOWNLOAD_TAG_p",downloaded+" <- "+cacheDownloadFile.getAbsolutePath());
} catch (IOException e) {
e.printStackTrace();
}
fireOnUpdate(ON_INIT,"init ...");
}
#Override
protected String doInBackground(String... params) {
try {
File dir=new File(fileDestination);
File chacheDir=new File(AppCostants.CHACHE_PATH);
if(!chacheDir.isDirectory())
chacheDir.mkdirs();
if(!dir.isDirectory()){
dir.mkdirs();
}
if(file.exists()) {
Log.d("FILE_DOWNLOAD_TAG","File exist return complete");
return "COMPLETED";//file exist
}
if(!cacheDownloadFile.exists()){
cacheDownloadFile.createNewFile();
}
Log.d("FILE_DOWNLOAD_TAG","LINK "+downloadlink);
URL url=new URL(downloadlink);
HttpURLConnection urlConnection= (HttpURLConnection) url.openConnection();
if(downloaded>0)
urlConnection.setRequestProperty("Range","byte="+downloaded);
urlConnection.connect();
int status = urlConnection.getResponseCode();
InputStream inputStream=urlConnection.getInputStream();
int totalSize=urlConnection.getContentLength();
if(totalSize<=downloaded){
returnData= "COMPLETED";
publishProgress("File checked "+Tools.getFileName(file.getAbsolutePath()));
return returnData;
}
this.downloadedPath=cacheDownloadFile.getAbsolutePath();
byte[] buffer=new byte[1024];
int bufferLength=0;
FileOutputStream fileOutput=new FileOutputStream(cacheDownloadFile);
long d=0;
long starttime=System.currentTimeMillis();
while ((bufferLength=inputStream.read(buffer))>0){
fileOutput.write(buffer,0,bufferLength);
downloaded+=bufferLength;
d+=bufferLength;
//String l=" "+Tools.getFileName(file.getAbsolutePath())+" ( "+Tools.convertMemory(downloaded)+" / "+Tools.convertMemory(totalSize)+" )";
String l=" "+Tools.convertMemory(downloaded)+" / "+Tools.convertMemory(totalSize)+" ( "+getDownloadSpeed(starttime,d)+" )";
publishProgress(l);
if(downloaded>=totalSize){
break;
}
}
Log.d("FILE_DOWNLOAD_TAG","DWONLOADED TO "+downloadedPath+" ("+cacheDownloadFile.length()+")");
fileOutput.close();
if(Tools.fileCopy(file,cacheDownloadFile)){
Log.d("FILE_DOWNLOAD_TAG","file Copied, delete cache");
cacheDownloadFile.delete();
}
returnData="COMPLETED";
} catch (MalformedURLException e) {
returnData=null;
e.printStackTrace();
publishProgress(e.toString());
Log.d("###################",e+"");
} catch (IOException e) {
returnData=null;
e.printStackTrace();
publishProgress(e.toString());
}
return returnData;
}
#Override
protected void onProgressUpdate(String... values) {
super.onProgressUpdate(values);
fireOnUpdate(ON_PROGRASS,values[0]);
}
#Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
if(s!=null){
fireOnUpdate(ON_COMPLETED,downloadedPath);
}else{
fireOnUpdate(ON_ERROR,"Download failed");
}
}
public interface onUpdateListener{
void onUpdate(int code,String message);
}
public void setOnUpdateListener(onUpdateListener onUpdateListener){
this.onUpdateListener=onUpdateListener;
}
private void fireOnUpdate(int code,String message){
if(onUpdateListener!=null)
onUpdateListener.onUpdate(code,message);
}
private String getDownloadSpeed(long starttime,float totalDownloaded) {
long elapsedTime = System.currentTimeMillis() - starttime;
//byte :
float speed=1000f * totalDownloaded / elapsedTime;
return convert(speed);
}
private String convert(float value){
long kb=1024
,mb=kb*1024
,gb=mb*1024;
if(value<kb){
String speed=(value+"");
speed=speed.substring(0,speed.indexOf('.')+2);
return speed+" B/s";
}else if(value<mb){
value=value/kb;
String speed=(value+"");
speed=speed.substring(0,speed.indexOf('.'));
return (speed)+" KB/s";
}else if(value<gb){
value=(value/mb);
String speed=(value+"");
speed=speed.substring(0,speed.indexOf('.'));
return speed+" MB/s";
}
return "";
}
}
use this code in onClick()
DownloadManager downloadManager = new DownloadManager(url,filepath);
set event
downloadManager.setOnUpdateListener(new DownloadManager.onUpdateListener() {
#Override
public void onUpdate(int code, String message) {
if (code == DownloadManager.ON_COMPLETED) {
}
if(DownloadManager.ON_PROGRASS==code){}
}
});
start download by
downloadManager.execute();
lib setup
compile "commons-io:commons-io:+"
Tools.java
public static long getFileSize(File file) throws IOException {
FileOutputStream fileOutputStream=new FileOutputStream(file);
fileOutputStream.close();
return file.length();
}
public static boolean fileCopy(File dest,File source){
try {
FileUtils.copyFile(source,dest);
return true;
} catch (IOException e) {
e.printStackTrace();
return false;
}
}
It is really bad idea to download file in main thread.
Use separate Thread for this
Thread thread = new Thread(new Runnable() {
#Override
public void run() {
//your downloading here
}
});
thread.start();
it`s better, but still not so good. There are some problems with it:
1) User know nothing about downloading
So better to show additional layout which overlays screen with progress bar, probably indeterminate if you want to write less code. Then after downloading is finished you just hide your layout.
You can use runOnUiThread inside run method in thread for it.
runOnUiThread(new Runnable() {
#Override
public void run() {
//just hide some popup
//or do what you want after downloading is finished
popupLayout.serVisibility(View.GONE);
}
});
2) If user will do action which re-creates activity/fragment (like changing screen orientaion) with running thread you will get memory leak and probably activity will not know about end of download.
There are few ways to solve this problem:
You can block screen orientation at this screen, at least while downloading. Probably easiest way in your case.
You can use downloading in foreground service. Its really good
practice, but you will have to learn about services.
You can try to interrupt downloading by calling thread.interrupt()
method in onDestroy of your Activity/Fragment
You can use something like rxJava/rxAndroid (so you don not use threads at all, but you need some time for learn rxJava)
UPD
About threads
Not so bad tutorial about threads in android
You can use AsyncTask instead of Thread, but I highly recommend to use threads especially for long operations.
I am working on a hidden camera application but I have some problems with taking photo.
When I debug the application, I can see that takePicture can be invoked but it doesn't call pictureCallback class.
I am putting class I am using and waiting for your helps.
public class TakePhotoClass {
private final String LOG_TAG="Photo Taker Class";
private Context context;
private Camera cam;
private Camera.PictureCallback pictureCallback;
private AudioManager audioManager;
public TakePhotoClass(Context con) {
// TODO Auto-generated constructor stub
context=con;
audioManager=(AudioManager) con.getSystemService(Context.AUDIO_SERVICE);
}
public void takePhoto(){
prepareCamera();
audioManager.setStreamMute(AudioManager.STREAM_SYSTEM, true);
try{
cam.startPreview();
cam.takePicture(null, null, pictureCallback);
}catch(Exception ex)
{
Log.e(LOG_TAG, "Couldn't be taken photo. Error message: "+ex.getLocalizedMessage());
}
}
private void prepareCamera(){
cam=Camera.open();
Camera.Parameters param=cam.getParameters();
param.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
param.setJpegQuality(100);
param.setFocusMode(param.FOCUS_MODE_AUTO);
param.setPictureFormat(ImageFormat.JPEG);
cam.setParameters(param);
SurfaceView view=new SurfaceView(context);
try {
cam.setPreviewDisplay(view.getHolder());
} catch (IOException e) {
// TODO Auto-generated catch block
Log.e(LOG_TAG, "Can not set surface");
}
setCallback();
}
private void setCallback(){
pictureCallback=new Camera.PictureCallback() {
#Override
public void onPictureTaken(byte[] data, Camera camera) {
// TODO Auto-generated method stub
try{
File parentFolder=new File(Environment.getExternalStorageDirectory()+"/Agent Cam/Photo");
File photoFile=new File(parentFolder,"photo_"+getPhotoTime()+".jpg");
if(!photoFile.exists())
photoFile.mkdirs();
FileOutputStream stream=new FileOutputStream(photoFile);
stream.write(data);
stream.flush();
stream.close();
audioManager.setStreamMute(AudioManager.STREAM_SYSTEM, false);
context.sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED,Uri.parse("file://"+Environment.getExternalStorageDirectory())));
camera.release();
}catch(Exception ex)
{
Log.e(LOG_TAG, "Photo coluldn't be saved. Error message: "+ex.getLocalizedMessage());
}
}
};
}
private String getPhotoTime(){
SimpleDateFormat sdf=new SimpleDateFormat("ddMMyy_hhmmss");
return sdf.format(new Date());
}
}
Camera.PictureCallback's method onPictureTaken is called asynchronously (see takePicture), your app should wait for it to be called.
I have an android application that is a client for a simple chat server. I am able to connect to the server and my ObjectStreams. The problem is when I receive a message, the thread that handles my server connection calls upon my display message which updates the list view.
I am getting the error "only the original thread that created a view hierarchy can touch its views."
I am pretty sure its because I'm calling my displayMessage() method from my connect thread, but I am not sure how to organize my threads to have a connection to the server and dynamically update my listview.
Here is my main activity.
public class MainActivity extends Activity {
private Connection serverConnection;
private ArrayList<String> listItems = new ArrayList<String>();
private ArrayAdapter<String> adapter;
/**
* Sets the ArrayAdaptor, and starts the connectThread.
*/
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
runOnUiThread(new Runnable() {
public void run() {
ListView listview = (ListView) findViewById(R.id.list);
adapter = new ArrayAdapter<String>(MainActivity.this,
android.R.layout.simple_list_item_1,
listItems);
listview.setAdapter(adapter);
}
});
/**
* Starts a new connection Thread
*/
Thread connectThread = new Thread(new Runnable(){
public void run(){
serverConnection = new Connection(MainActivity.this);
serverConnection.run();
}
});
connectThread.start();
}
/**
* Adds a message to the list view.
* #param string - message to be added.
*/
public void displayMessage(String string) {
listItems.add(string);
adapter.notifyDataSetChanged();
}
}
Here is my connection thread class.
public class Connection extends Thread {
private Socket client;
private ObjectOutputStream output;
private ObjectInputStream input;
private MainActivity mainActivity;
private String message;
/**
* Constructor starts the socket and ObjectStreams
*
* #param mainActivity - reference to the MainActivity
*/
public Connection(MainActivity mainActivity) {
this.mainActivity = mainActivity;
try {
client = new Socket("192.168.1.105", 50499);
mainActivity.displayMessage("Connected to: "
+ client.getInetAddress().getHostName());
output = new ObjectOutputStream(client.getOutputStream());
output.flush();
input = new ObjectInputStream(client.getInputStream());
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* Run method for the Thread.
*/
public void run() {
for (;;) {
try {
message = (String) input.readObject();
mainActivity.displayMessage(message);
} catch (OptionalDataException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
You are updating Ui on the background thread. You should update ui on the ui thread. Move your code that updates ui in the background thread. You are refreshing your listview on the background thread.
mainActivity.displayMessage("Connected to: "
+ client.getInetAddress().getHostName());
mainActivity.displayMessage(message);
public void displayMessage(String string) {
listItems.add(string);
adapter.notifyDataSetChanged();
}
The above should be outside the thread or You can use runonuithread inside the thread to update ui.
runOnUiThread(new Runnable() {
#Override
public void run() {
// update ui
}
});
Another way would be to use asynctask. Do all your network related operation in doInbackground() and update ui in onPostExecute().
Async Task
Edit: Not sure what you are trying to do.
public class MainActivity extends Activity {
private Connection serverConnection;
private ArrayList<String> listItems = new ArrayList<String>();
private ArrayAdapter<String> adapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ListView listview = (ListView) findViewById(R.id.lv);
adapter = new ArrayAdapter<String>(MainActivity.this,
android.R.layout.simple_list_item_1,
listItems);
listview.setAdapter(adapter);
// use a button and on button click start the thread.
Thread connectThread = new Thread(new Runnable(){
public void run(){
serverConnection = new Connection(MainActivity.this);
serverConnection.run();
}
});
connectThread.start();
}
public void displayMessage(String string) {
listItems.add(string);
adapter.notifyDataSetChanged();
}
class Connection extends Thread {
private Socket client;
private ObjectOutputStream output;
private ObjectInputStream input;
private MainActivity mainActivity;
private String message;
public Connection(MainActivity mainActivity) {
this.mainActivity = mainActivity;
try {
client = new Socket("192.168.1.105", 50499);
runOnUiThread(new Runnable() {
#Override
public void run() {
displayMessage("Connected to: "
);
}
});
output = new ObjectOutputStream(client.getOutputStream());
output.flush();
input = new ObjectInputStream(client.getInputStream());
} catch (IOException e) {
e.printStackTrace();
}
}
public void run() {
for (;;) {
try {
message = (String) input.readObject();
runOnUiThread(new Runnable() {
#Override
public void run() {
displayMessage(message);
}
});
} catch (OptionalDataException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
I have the following problem. I am using the DropBox SDK to upload a file to dropbox which works fine. When the file is being uploaded (inside an AsyncTask) a ProgressDialog is being shown with a cancel button, still fine here. What is not working fine is, when the cancel button gets pressed a NetworkOnMainThreadException is being raised. I am new to Android programming but I am suspecting it has something to do with the ProgressDialog which is in the constructor. Since it is not in the "doInBackground" part.
Tried to fix it with implementing the OnDismissListener and doing the abortion onDismiss but still no luck. I am getting the error when "mRequest.abort()" is called.
Thanks in advance for any answers!
So here is my code
public class DropBoxUpload extends AsyncTask<Void, Long, Boolean> implements OnDismissListener {
private DropboxAPI<?> mApi;
private String mPath;
private File mFile;
private long mFileLen;
private UploadRequest mRequest;
private Context mContext;
private final ProgressDialog mDialog;
private String mErrorMsg;
public DropBoxUpload(Context context, DropboxAPI<?> api, String dropboxPath, File file) {
// We set the context this way so we don't accidentally leak activities
mContext = context.getApplicationContext();
mFileLen = file.length();
mApi = api;
mPath = dropboxPath;
mFile = file;
mDialog = new ProgressDialog(context);
mDialog.setMax(100);
mDialog.setMessage("Uploading " + file.getName());
mDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
mDialog.setProgress(0);
mDialog.setButton("Cancel", new OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// This will cancel the putFile operation
mDialog.dismiss();
}
});
mDialog.setCancelable(true);
mDialog.setOnDismissListener(this);
mDialog.show();
}
#Override
protected Boolean doInBackground(Void... params) {
try {
// By creating a request, we get a handle to the putFile operation,
// so we can cancel it later if we want to
FileInputStream fis = new FileInputStream(mFile);
String path = mPath + mFile.getName();
mRequest = mApi.putFileOverwriteRequest(path, fis, mFile.length(),
new ProgressListener() {
#Override
public long progressInterval() {
// Update the progress bar every half-second or so
return 500;
}
#Override
public void onProgress(long bytes, long total) {
publishProgress(bytes);
}
});
if (mRequest != null) {
mRequest.upload();
return true;
}
} catch (DropboxUnlinkedException e) {
// This session wasn't authenticated properly or user unlinked
mErrorMsg = "This app wasn't authenticated properly.";
} catch (DropboxFileSizeException e) {
// File size too big to upload via the API
mErrorMsg = "This file is too big to upload";
} catch (DropboxPartialFileException e) {
// We canceled the operation
mErrorMsg = "Upload canceled";
} catch (DropboxServerException e) {
// Server-side exception. These are examples of what could happen,
// but we don't do anything special with them here.
if (e.error == DropboxServerException._401_UNAUTHORIZED) {
// Unauthorized, so we should unlink them. You may want to
// automatically log the user out in this case.
} else if (e.error == DropboxServerException._403_FORBIDDEN) {
// Not allowed to access this
} else if (e.error == DropboxServerException._404_NOT_FOUND) {
// path not found (or if it was the thumbnail, can't be
// thumbnailed)
} else if (e.error == DropboxServerException._507_INSUFFICIENT_STORAGE) {
// user is over quota
} else {
// Something else
}
// This gets the Dropbox error, translated into the user's language
mErrorMsg = e.body.userError;
if (mErrorMsg == null) {
mErrorMsg = e.body.error;
}
} catch (DropboxIOException e) {
// Happens all the time, probably want to retry automatically.
mErrorMsg = "Network error. Try again.";
} catch (DropboxParseException e) {
// Probably due to Dropbox server restarting, should retry
mErrorMsg = "Dropbox error. Try again.";
} catch (DropboxException e) {
// Unknown error
mErrorMsg = "Unknown error. Try again.";
} catch (FileNotFoundException e) {
}
return false;
}
#Override
protected void onProgressUpdate(Long... progress) {
int percent = (int)(100.0*(double)progress[0]/mFileLen + 0.5);
mDialog.setProgress(percent);
}
#Override
protected void onPostExecute(Boolean result) {
mDialog.dismiss();
}
#Override
public void onDismiss(DialogInterface arg0) {
// TODO Auto-generated method stub
mRequest.abort();
}
}
You cannot access the mRequest object from the main UI thread as this is what is responsible for the network operation. That is why you get a NetworkOnMainThreadException when you call mRequest.abort().
You should modify your code such that you use AsyncTask.cancel on dialog dismissal and check for isCancelled periodically in your doInBackground and call mRequest.abort() when the task is cancelled.
you should call the cancel method to stop your uploading process.
ast.cancel(true);
where ast is your asynctask object
I have book with lessons about android . Now i realize help screen when i have many text . In book type about text . that android sdk can use txt files with many text . and in book typed code but when im use him , it doesent work (my app launch but i dont have any text on screen ) what's wrong? Help with right variant . my code :
package com.lineage.goddess;
import java.io.InputStream;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class LineageHelpActivity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.help);
openRawResource();
InputStream iFile = getResources().openRawResource(R.raw.lineagehelp);
TextView helpText =(TextView) findViewById(R.id.TextView_HelpText);
String strFile = inputStreamToString(iFile);
helpText.setText(strFile);
}
private String inputStreamToString(InputStream iFile) {
// TODO Auto-generated method stub
return null;
}
private void openRawResource() {
// TODO Auto-generated method stub
}
}
Well... for one, you are returning null from inputStreamToString(...). You need to implement it correctly before you can expect it to return anything.
change
private String inputStreamToString(InputStream iFile) {
// TODO Auto-generated method stub
return null;
}
with
private String inputStreamToString(InputStream iFile)
{
Writer writer = new StringWriter();
if(iFile!=null)
{
char[] buffer = new char[1024];
try{
Reader reader = new BufferedReader(
new InputStreamReader(iFile, "UTF-8"));
int n;
while ((n = reader.read(buffer)) != -1) {
writer.write(buffer, 0, n);
}
} catch (UnsupportedEncodingException e) {
return e.toString();
} catch (IOException e) {
return e.toString();
}finally
{
try {
iFile.close();
} catch (IOException e) {
return e.toString();
}
}
}
String result = writer.toString();
return result;
}