Setting window layout after calling setContentView()

Question

I am creating an activity that as a dialog format: it does not cover the whole screen, but only part of it. What I did was in the onCreate() method of this activity, after calling setContentView(), I call:

window.setLayout(windowWidthInDp, LayoutParams.WRAP_CONTENT);

And it does not work. I need to do the following instead to make it work:

window.getDecorView().post(new Runnable() { 
    @Override 
    public void run() { 
        window.setLayout(windowWidthInDp, LayoutParams.WRAP_CONTENT); 
    } 
});

Again, this is AFTER setContentView() is called. Why do I have to pose it into the message queue instead of calling it directly? Thanks!

score 1 · Accepted Answer · answered Dec 09 '16 at 19:30

1

Setting the content view just gives the layout to the Android framework. The layout hasn't yet been fully configured. This doesn't happen until the Android framework gets control back (ie: in the next event loop). This won't happen until the onCreate() method ends.

By posting your code to a Handler, you delay the execution of that code until after the Android framework has fully configured the layout.

answered Dec 09 '16 at 19:30

David Wasser

93,459
16
209
274

Thank you for replying! Is there some other signal for the layout being fully configured (other than the onCreate() method is returned)? – seemuch Dec 09 '16 at 21:14
1

Some people are using `ViewTreeObserver's addOnGlobalLayoutListener()`. – David Wasser Dec 10 '16 at 07:02
1

See http://stackoverflow.com/questions/4393612/when-can-i-first-measure-a-view for more information. Here someone suggests using `ViewTreeObserver.addOnPreDrawListener()` – David Wasser Dec 10 '16 at 07:09
Noted. Thanks you! – seemuch Dec 12 '16 at 21:13

Setting window layout after calling setContentView()

1 Answers1