Question

I’m currently trying to animate the position of a button using a TranslateAnimation. I’ve read in multiple places that the way to make the actual button move as well as the drawable is to change its layout after the animation. I’ve done that, but I’ve run into two problems/solutions:

1. Either I add setFillAfter( true ). This is nice because the drawable persists after the animation, but when the layout is changed, the drawable is offset from where it should be by the translation distance, while the blank frame of the button is now where it should be.

2. Add setFillAfter( false ). Doing this and then setting the layout after the animation works like it should, but the icon will flash, I assume this is the delay between the ending of the animation and the refresh of the screen with the new layout parameters. I’m currently using this code, but the flash is unacceptable, so I’d like to find a solution to fix it.

Here’s my code currently:

final View aniView = v;  // v is some view
TranslateAnimation ani = new TranslateAnimation(0, 
240 - v.getLeft() - v.getWidth() / 2, 
0, 
240 - v.getTop() - v.getHeight() / 2 );


ani.setDuration( 500 );

ani.setFillAfter( false );
ani.setAnimationListener( new AnimationListener() {
public void onAnimationEnd( Animation a ) {
        aniView.setTag( new Boolean( true ) );
    RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams( aniView.getWidth(), 
    aniView.getHeight() );
    params.leftMargin = 240 - aniView.getWidth() / 2;
    params.topMargin = 240 - aniView.getHeight() / 2;

    aniView.setLayoutParams(params);
}
public void onAnimationStart( Animation a ) {}
public void onAnimationRepeat( Animation a ) {}
});
v.animationStart( ani );

Answer 1

I’ve figured out the solution to my own question, and will post the code for anyone who comes across the same problem. Basically the idea is to set the layout params before hand and essentially reverse the animation. Here’s the idea:

TranslateAnimation ani = new TranslateAnimation(v.getLeft() + v.getWidth() / 2 - 240 , 
                0, 
                v.getTop() + v.getHeight() / 2 - 240, 
                0);


        ani.setDuration( 500 );
        ani.setFillAfter( true );
        ani.setDuration( 1000 );
        ani.setFillAfter( true );
        ani.setAnimationListener( new AnimationListener() {
            public void onAnimationEnd( Animation a ) {
                aniView.setTag( new Boolean( true ) );
            }
            public void onAnimationStart( Animation a ) {}
            public void onAnimationRepeat( Animation a ) {}
        });

        RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams( v.getWidth(), 
                v.getHeight() );
        params.leftMargin = 240 - aniView.getWidth() / 2;
        params.topMargin = 240 - aniView.getHeight() / 2;

        v.setLayoutParams(params);
        v.startAnimation( set );