View.invalidate() Not Working To Redraw Imageview

Ok guys, this may sound dumb, but I have been banging my head against the keyboard for some time now trying to figure out why this will not refresh. the basics: I have a little sam

Solution 1:

I think what you did was something like:

for (int degrees = 0 ; degrees < maxRotation ; i++) {
    // perform the rotation by matrix
    myImageView.invalidate();
}

This wouldn't work because invalidate() only schedules a redraw in the main thread event queue. This means that the redraw will be performed only when the current code has all been executed (in this case, the for cycle).

For a simple rotation a Tween Animation would be better suited. For more advanced stuff (like game animations) you might need to create a custom view or use SurfaceView.

Solution 2:

Sounds like you're blocking the UI thread with your code to rotate the image.

I don't have any code to show you right now (reply back and when I'm home tonight I can post something that should help), but yuo will probably get better results placing your rotate code in an AsyncTask, see the Painless Threading area of the dev site for more info.

Solution 3:

I was having the same problem, i used:

runOnUiThread(new Runnable() {
    public void run() {
    myImageView.setImageBitmap(image);
    imageView.invalidate();
    }
});