android - 如何用动画扩展布局高度？

Question

我找不到一个很好的例子来说明如何做到这一点。

我有一个设置为 x 高度的 RelativeLayout。

我想添加一个将高度扩展到 x+y 高度的按钮。

有人可以向我推荐一个如何以编程方式执行此操作的好例子吗？

Answer 1

您标记了最接近的解决方案。这是确切的解决方案。我有同样的问题。希望这个答案对其他人有所帮助。

实例化ResizeAnimation

ResizeAnimation resizeAnimation = new ResizeAnimation(
     view, 
     targetHeight, 
     startHeight
); 
resizeAnimation.setDuration(duration); 
view.startAnimation(resizeAnimation);

ResizeAnimation 类应该是这样的

public class ResizeAnimation extends Animation {
    final int targetHeight;
    View view;
    int startHeight;

    public ResizeAnimation(View view, int targetHeight, int startHeight) {
        this.view = view;
        this.targetHeight = targetHeight;
        this.startHeight = startHeight;
    }

    @Override
    protected void applyTransformation(float interpolatedTime, Transformation t) {
        int newHeight = (int) (startHeight + targetHeight * interpolatedTime);
        //to support decent animation, change new heigt as Nico S. recommended in comments
        //int newHeight = (int) (startHeight+(targetHeight - startHeight) * interpolatedTime);
        view.getLayoutParams().height = newHeight;
        view.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;
    }
}