如何使用ViewPropertyAnimator将宽度设置为特定值

Question

如何使用ViewPropertyAnimator设置视图宽度？

我可以缩放或平移(见下文)，但是我不能设置一个特定的宽度。

frame_1.animate().scaleX(5).scaleY(5).start();

但是没有

frame_1.animate().width(1024).height(768).start();

Answer 1

使用简单的动画代替ViewPropertyAnimator

public class ResizeWidthAnimation extends Animation
{ 
    private int mWidth;
    private int mStartWidth;
    private View mView;

    public ResizeWidthAnimation(View view, int width)
    { 
        mView = view;
        mWidth = width;
        mStartWidth = view.getWidth();
    } 

    @Override 
    protected void applyTransformation(float interpolatedTime, Transformation t)
    { 
        int newWidth = mStartWidth + (int) ((mWidth - mStartWidth) * interpolatedTime);

        mView.getLayoutParams().width = newWidth;
        mView.requestLayout();
    } 

    @Override 
    public void initialize(int width, int height, int parentWidth, int parentHeight)
    { 
        super.initialize(width, height, parentWidth, parentHeight);
    } 

    @Override 
    public boolean willChangeBounds() 
    { 
            return true; 
    } 
} 

Answer 2

试试这个，即使是Android 2.3也支持：

    ValueAnimatorCompat exitAnimator = AnimatorCompatHelper.emptyValueAnimator();
    exitAnimator.setDuration(TransitCompat.ANIM_DURATION * 4);
    exitAnimator.addUpdateListener(new AnimatorUpdateListenerCompat() {
        private float oldWidth =  view.getWidth();
        private float endWidth = 0;
        private float oldHeight =  view.getHeight();
        private float endHeight = 0;
        private Interpolator interpolator2 = new BakedBezierInterpolator();//Any other will be also O.K.

        @Override
        public void onAnimationUpdate(ValueAnimatorCompat animation) {
            float fraction = interpolator2.getInterpolation(animation.getAnimatedFraction());

            float width =  oldWidth + (fraction * (endWidth - oldWidth));
            mTarget.get().getLayoutParams().width = (int) width;

            float height =  oldHeight + (fraction * (endHeight - oldHeight));
            view.getLayoutParams().height = (int) height;


            view.requestLayout();
        }
    });

    exitAnimator.start();