How to display progress dialog before starting an activity in Android?

Question

How do you display a progress dialog before starting an activity (i.e., while the activity is loading some data) in Android?

Answer 1

You should load data in an AsyncTask and update your interface when the data finishes loading.

You could even start a new activity in your AsyncTask's onPostExecute() method.

More specifically, you will need a new class that extends AsyncTask:

public class MyTask extends AsyncTask<Void, Void, Void> {   public MyTask(ProgressDialog progress) {     this.progress = progress;   }    public void onPreExecute() {     progress.show();   }    public void doInBackground(Void... unused) {     ... do your loading here ...   }    public void onPostExecute(Void unused) {     progress.dismiss();   } } 

Then in your activity you would do:

ProgressDialog progress = new ProgressDialog(this); progress.setMessage("Loading..."); new MyTask(progress).execute(); 

Answer 2

When you start a long-running process on Android, its always advisable to do it on another thread. You can then use the UI thread to display a progress dialog. You cannot display a progress dialog in the same (UI) thread in which the process is running.

Do the following to start your process

pd = ProgressDialog.show(this, "Synchronizing data", "Please wait..."); Thread t = new Thread(this); t.start(); 

For this your activity should implement Runnable as follows

public class SyncDataActivity extends Activity implements Runnable 

And finally a method to perform the long-running process

@Override public void run() {       //your code here }