i have an asyncTaskProc that read some info from a DB and write it on the ui...
the code works perfectcly on Android 4.0 but doesn't work on 2.3... here is the code
NEW ASYNCTASK
`public class IceCastPoll extends TimerTask {
public IceCastPoll() {
}
@TargetApi(9)
public void run() {
new AsyncTaskProc().execute();
}
}`
THE ASYNCTASK implementation
@TargetApi(9)
class AsyncTaskProc extends AsyncTask<Void, String, Void> {
List<Stream> streams=null;
@Override
protected void onPostExecute(Void result) {
textSong =(TextView) findViewById(R.id.textViewCurrentSong);
textArtist =(TextView) findViewById(R.id.textViewCurrentArtist);
textTit=(TextView) findViewById(R.id.textViewTit);
textArt=(TextView) findViewById(R.id.TextViewArt);
copertina=(ImageView) findViewById(R.id.imageViewCopertina);
new DownloadImageTask((ImageView) findViewById(R.id.imageViewCopertina)).execute("http://service.uniradiocesena.it/OnAir.jpg");
try {
for (Stream stream: streams) {
try
{
//Thread.sleep(5000);
//textSong.setText((stream.getCurrentSong()));
textArt.setText("Artista:");
textTit.setText("Titolo:");
StringTokenizer tokens = new StringTokenizer(stream.getCurrentSong(), "-");
String first = tokens.nextToken();
String second = tokens.nextToken();
textSong.setText(first);
textArtist.setText(second);
} catch (Exception e) {
//Thread.sleep(5000);
textSong.setText((stream.getCurrentSong()));
textArt.setText("Rotazione:");
textTit.setText("");
textArtist.setText("");
}
}
} catch (Exception e) {
//Toast.makeText(getApplicationContext(),e.toString(), Toast.LENGTH_SHORT).show();
}
}
@Override
protected Void doInBackground(Void... unused) {
Scraper scraper = new IceCastScraper();
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
try {
streams = scraper.scrape(new URI("http://r35798.ovh.net:8000/"));
} catch (ScrapeException e) {
// TODO Auto-generated catch block
e.printStackTrace();
//Toast.makeText(getApplicationContext(),e.toString(), Toast.LENGTH_LONG).show();
} catch (URISyntaxException e) {
// TODO Auto-generated catch block
e.printStackTrace();
//Toast.makeText(getApplicationContext(),e.toString(), Toast.LENGTH_LONG).show();
}
return (null);
}
}`
THE LOGCAT ERRORS
11-07 11:09:49.729: W/dalvikvm(18983): Exception Ljava/lang/RuntimeException; thrown while initializing Landroid/os/AsyncTask;
11-07 11:09:49.729: W/dalvikvm(18983): threadid=9: thread exiting with uncaught exception (group=0x40018560)
11-07 11:09:49.739: E/AndroidRuntime(18983): FATAL EXCEPTION: Timer-0
11-07 11:09:49.739: E/AndroidRuntime(18983): java.lang.ExceptionInInitializerError
11-07 11:09:49.739: E/AndroidRuntime(18983): at com.example.appuniradiocesena.SwipeyTabsSampleActivity$IceCastPoll.run(SwipeyTabsSampleActivity.java:233)
11-07 11:09:49.739: E/AndroidRuntime(18983): at java.util.Timer$TimerImpl.run(Timer.java:284)
11-07 11:09:49.739: E/AndroidRuntime(18983): Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
11-07 11:09:49.739: E/AndroidRuntime(18983): at android.os.Handler.<init>(Handler.java:121)
11-07 11:09:49.739: E/AndroidRuntime(18983): at android.os.AsyncTask$InternalHandler.<init>(AsyncTask.java:421)
11-07 11:09:49.739: E/AndroidRuntime(18983): at android.os.AsyncTask$InternalHandler.<init>(AsyncTask.java:421)
11-07 11:09:49.739: E/AndroidRuntime(18983): at android.os.AsyncTask.<clinit>(AsyncTask.java:152)
11-07 11:09:49.739: E/AndroidRuntime(18983): ... 2 more
Any suggestion it will be very very apreciated !
and sry for english mistakes :D
In summary, the three most common issues with AsyncTask are: Memory leaks. Cancellation of background work. Computational cost.
An asynchronous task is defined by a computation that runs on a background thread and whose result is published on the UI thread. An asynchronous task is defined by 3 generic types, called Params , Progress and Result , and 4 steps, called onPreExecute , doInBackground , onProgressUpdate and onPostExecute .
3. AsyncTask deprecated alternative Android – Kotlin. Here, we are using the Executor class as an alternative to the deprecated AsyncTask. A Handler gives you a mechanism to push tasks into the UI thread queue from any other threads thus allowing other threads to communicate with the UI thread.
Use getStatus() to get the status of your AsyncTask . If status is AsyncTask. Status. RUNNING then your task is running.
You should start AsyncTask with a Handler created on main thread. So replace your run()
method in IceCastPoll with this one:
private Handler handler = new Handler(Looper.getMainLooper());
@Override
public void run() {
handler.post(new Runnable() {
public void run() {
new AsyncTaskProc().execute();
}
});
}
new AsyncTaskProc().execute();
Dont put this code inside a thread .
Because it is already a Handler.
Simple Execute the code where ever you need like new AsyncTaskProc().execute(); its enough my Friend
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