Android: How to work with background thread?
I've developed an application that takes content from the internet and shows it accordingly on the device's screen . The program works just fine , a little bit slow . It takes about 3-4 seconds to load and display the content . I would like to put all the code that fetches the content and displays it in a background thread and while the program is doing those functions , I would like to display a progress dialog. Could you help me do this ? I would like especially to learn how to put the code in a background thread.
MY CODE
public class Activity1 extends Activity
{
private ProgressDialog progressDialog;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
new AsyncTask<Integer, Integer, Boolean>()
{
ProgressDialog progressDialog;
@Override
protected void onPreExecute()
{
/*
* This is executed on UI thread before doInBackground(). It is
* the perfect place to show the progress dialog.
*/
progressDialog = ProgressDialog.show(Activity1.this, "",
"Loading...");
}
@Override
protected Boolean doInBackground(Integer... params)
{
if (param开发者_运维百科s == null)
{
return false;
}
try
{
/*
* This is run on a background thread, so we can sleep here
* or do whatever we want without blocking UI thread. A more
* advanced use would download chunks of fixed size and call
* publishProgress();
*/
Thread.sleep(params[0]);
// HERE I'VE PUT ALL THE FUNCTIONS THAT WORK FOR ME
}
catch (Exception e)
{
Log.e("tag", e.getMessage());
/*
* The task failed
*/
return false;
}
/*
* The task succeeded
*/
return true;
}
@Override
protected void onPostExecute(Boolean result)
{
progressDialog.dismiss();
/*
* Update here your view objects with content from download. It
* is save to dismiss dialogs, update views, etc., since we are
* working on UI thread.
*/
AlertDialog.Builder b = new AlertDialog.Builder(Activity1.this);
b.setTitle(android.R.string.dialog_alert_title);
if (result)
{
b.setMessage("Download succeeded");
}
else
{
b.setMessage("Download failed");
}
b.setPositiveButton(getString(android.R.string.ok),
new DialogInterface.OnClickListener()
{
@Override
public void onClick(DialogInterface dlg, int arg1)
{
dlg.dismiss();
}
});
b.create().show();
}
}.execute(2000);
new Thread()
{
@Override
public void run()
{
// dismiss the progressdialog
progressDialog.dismiss();
}
}.start();
}
}
Check ASyncTask, its specifically created for such tasks.
public Runnable NameOfRunnable = new Runnable()
{
@Override
public void run()
{
while (true)
{
// TODO add code to refresh in background
try
{
Thread.sleep(1000);// sleeps 1 second
}
catch (InterruptedException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
};
now start this with
Thread name = new Thread(NameOfRunnable);
name.start();
How to work with Background Thread.
Note:
Do not work with UI with this background thread.AsyncTask.execute(new Runnable() {
@Override
public void run() {
//TODO background code
}
});
Hope this would help you.
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