视差效果

public class MyListView extends ListView {
    private ImageView imageView;
    private int height;
    private int maxHeight;

    public MyListView(Context context) {
        this(context,null);
    }
    public MyListView(Context context, AttributeSet attrs) {
        this(context, attrs ,0);
    }
    public MyListView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }
    /**
     * 在listView滑动到头的时候执行，可以获取到继续滑动的距离和方向
     * @param deltaY 继续滑动y方向的距离
     * @param maxOverScrollY y方向最大可以滚动的距离
     * @param isTouchEvent true表示手指拖动滑动 false表示fling靠惯性滑动
     * @return
     */
    @Override
    protected boolean overScrollBy(int deltaX, int deltaY, int scrollX, int scrollY, int scrollRangeX, int scrollRangeY, int maxOverScrollX, int maxOverScrollY, boolean isTouchEvent) {
        if(deltaY < 0 && isTouchEvent){
            int newHeight = imageView.getHeight() - deltaY /3;
            if(newHeight > maxHeight) newHeight = maxHeight;
            imageView.getLayoutParams().height = newHeight;
            imageView.requestLayout();
        }
        return super.overScrollBy(deltaX, deltaY, scrollX, scrollY, scrollRangeX, scrollRangeY, maxOverScrollX, maxOverScrollY, isTouchEvent);
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        if(ev.getAction() == MotionEvent.ACTION_UP){
            ValueAnimator animator = ValueAnimator.ofInt(imageView.getHeight(),height);
            animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
                @Override
                public void onAnimationUpdate(ValueAnimator animation) {
                    imageView.getLayoutParams().height = (int) animation.getAnimatedValue();
                    imageView.requestLayout();
                }
            });
            animator.setInterpolator(new OvershootInterpolator(5));
            animator.setDuration(350);
            animator.start();
        }
        return super.onTouchEvent(ev);
    }

    public void setImageView(final ImageView imageView) {
        this.imageView = imageView;
        imageView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN)
            @Override
            public void onGlobalLayout() {
                imageView.getViewTreeObserver().removeOnGlobalLayoutListener(this);
                int intrinsicHeight = imageView.getDrawable().getIntrinsicHeight();
                height = imageView.getHeight();
                maxHeight = intrinsicHeight > height ? intrinsicHeight : height*2;
                maxHeight =  height*2;
            }
        });
    }
}