Show ProgressDialog while loading layout with setContentView

Question

this is my scenario: I've got a login screen that opens another activity. In the Activity I simply have:

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_details);
}

The layout is kind of heavy, cause it is made of some fragments, and takes about 1.5 seconds to load. Now, how can I display a ProgressDialog while setContentView finishes inflating the layout? I've tried with AsyncTask by putting the setContentView in the doInBackground, but of course that cannot be done, as the UI can be updated from the UI thread only. So I need to call setContentView in the UI thread, but where do I have to show/dismiss the ProgressDialog?

I appreciate your help.

Fra.

EDIT: I followed @JohnBoker's previous suggestion, this is the code I have now:

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_empty_layout);
    new ContentSetterTask().execute("");
}

private class ContentSetterTask extends AsyncTask<String, Void, Void> {

    public ProgressDialog prgDlg;

    @Override
    protected void onPreExecute() {
        android.os.Debug.waitForDebugger();
        prgDlg = ProgressDialog.show(MultiPaneActivity.this, "", "Loading...", true);

    }

@Override
protected Void doInBackground(String... args) {
    android.os.Debug.waitForDebugger();
    ViewGroup rootView = (ViewGroup)findViewById(R.id.emptyLayout);
    LayoutInflater inflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    View inflated = inflater.inflate(R.layout.activity_details, rootView);
    return null;
}

@Override
protected void onPostExecute(Void arg) {
    android.os.Debug.waitForDebugger();
    if (prgDlg.isShowing())
        prgDlg.dismiss();
    }
  }
}

The row

View inflated = inflater.inflate(R.layout.activity_details, rootView);

gives me the error:

06-27 16:47:24.010:   
ERROR/AndroidRuntime(8830): Caused by:android.view.ViewRoot$CalledFromWrongThreadException: 
Only the original thread that created a view hierarchy can touch its views.

Answer 1

I decided to make a full answer here for future readers.

After several hours spent on the issue, I realized that the issue is I'm trying to do two things:

1. inflating a layout, which is an operation that NEEDS to be made on the UI thread by design.
2. showing a Dialog (ProgressDialog, actually, but this does not change the outcome), that can be done from the UI thread only, since Services can't show any Dialog.

So, as both calls are made from the UI thread (onCreate or AsyncTask makes no difference, it's still the UI thread), the first blocks the second one from showing up appropriately. Bottom line is: this problem can't be solved in Android right now. Let's hope we can get some better APIs for interacting with the UI, because the ones we've got kind of suck.

I'm going to solve this problem by changing the layout and making it lighter (if possible!). Thanks everyone!

Answer 2

I had the same issue when creating a heavy view, what I did was put a linearlayout only in the xml file and called the setContentView on that, then i created the real view in the asynctask and added the view dymanically to the linearlayout.

This method seems to work and i was able to put a progress dialog up during the process.

Answer 3

This is not a perfect solution, but so far the closest one to what I needed: We need some time between setting the progress dialog (or message view or whatever) visible and calling setContentView(), so that the dialog/message is actually displayed.

To achieve that, I start a Thread performing a short sleep(), then calling setContentView() in the UI thread.

Here is an example with a progress dialog:

private ProgressDialog  m_Hourglass = null ;
private Thread          m_LoadingThread = null ;

...

public void onCreate( Bundle savedInstanceState )
{
    super.onCreate( savedInstanceState );

    ...

    m_Hourglass = new ProgressDialog( this );
    m_Hourglass.setMessage( "Loading" );
    m_Hourglass.setIndeterminate( true );
    m_Hourglass.setCancelable( false );
}

public void SetMyView( View vvv )                   // Can be called from buttons.
{
    if( m_LoadingThread != null ) return;           // Avoid multiple press

    m_Hourglass.show();

    ////////////////////////////////////////////////////
    // Load in a thread, just to show the above message
    // before changing layout (because setContentView()
    // freezes the GUI.)
    m_LoadingThread = new Thread()
    {
            @Override
            public void run()
            {
                super.run();
                try                 {   sleep( 20 ); }
                catch (Exception e) {   System.out.println( e ); }
                finally             {   runOnUiThread( new Runnable()
                                        {
                                            public void run() 
                                            {
                                                SetMyViewThreaded();
                                            }
                                        });
                                    }
                m_LoadingThread = null ; // Now we can load again
            }
    };
    m_LoadingThread.start();
}

public void SetMyViewThreaded()
{
    setContentView( R.layout.some_gorgeous_layout );

    /////////////////////////////////////////////////////
    // Catch when to finally hide the progress dialog:
    ImageView iv            = (ImageView) findViewById( R.id.some_view_in_the_layout );
    ViewTreeObserver obs    = iv.getViewTreeObserver();      
    obs.addOnGlobalLayoutListener( new OnGlobalLayoutListener()
    {          
         @Override          
         public void onGlobalLayout()    // The view is now loaded
         {
             m_Hourglass.hide();
         }      
    });

    //////////////////////////////////////////////////////
    // Here we can work on the layout
    ...
}

My main issue with this is the sleep( 20 ), which is an approximation, and may not be enough on all machines. It works for me, but if you don't see the progress dialog, you probably have to increase the sleep duration.