java - Android布局上的折叠动画

Question

我遇到了这个问题，我有一个类似 Accordion 的 Activity ，带有根据其状态展开或折叠布局的按钮，然后问题出在动画中，展开动画非常完美，但折叠布局时折叠动画它通过父按钮上方，我想折叠它相对于布局。

对不起，我的英语不好，这是代码:

public class Animations extends Animation {

/**
 * Initializes expand collapse animation, has two types, collapse (1) and expand (0).
 * @param view The view to animate
 * @param duration
 * @param type The type of animation: 0 will expand from gone and 0 size to visible and layout size defined in xml. 
 * 1 will collapse view and set to gone
 */
public AnimationSet AnimationSet;

public Animations(String type) {
    if (type == "Expand")
        AnimationSet = ExpandAnimation();
    if (type == "Collapse")
        AnimationSet =  CollapseAnimation();    
}
public AnimationSet ExpandAnimation() {

    AnimationSet _set = new AnimationSet(true);

      Animation animation = new AlphaAnimation(0.0f, 1.0f);
      animation.setDuration(250);
      _set.addAnimation(animation);

      animation = new TranslateAnimation(
          Animation.RELATIVE_TO_SELF, 0.0f, Animation.RELATIVE_TO_SELF, 0.0f,
          Animation.RELATIVE_TO_SELF, -1.0f, Animation.RELATIVE_TO_SELF, 0.0f
      );
      animation.setDuration(150);
      _set.addAnimation(animation);

      return _set;

}
public AnimationSet CollapseAnimation() {

    AnimationSet set = new AnimationSet(true);

      Animation animation = new AlphaAnimation(1.0f, 1.0f);
      animation.setDuration(250);
      set.addAnimation(animation);

      animation = new TranslateAnimation(
          Animation.RELATIVE_TO_SELF, 0.0f, Animation.RELATIVE_TO_SELF, 0.0f,
          Animation.RELATIVE_TO_SELF, 0.0f, Animation.RELATIVE_TO_SELF, -1.0f
      );
      animation.setDuration(250);
      set.addAnimation(animation);

      return set;

}

Answer 1

为什么不直接使用 ReverseInterpolator 来反转已经非常完美的展开动画？

public class ReverseInterpolator implements Interpolator {
    public float getInterpolation(float paramFloat) {
        return Math.abs(paramFloat -1f);
    }
}

在您的 _set 变量上:

_set.setInterpolator(new ReverseInterpolator());

或

public AnimationSet CollapseAnimation() {
    AnimationSet set = someObj.ExpandAnimation();
    set.setInterpolator(new ReverseInterpolator());
    return set;
}

我还要强调一些您做错的事情:

使用.equals 来比较字符串而不是==。这是错误的 -> if (type == "Expand")。此外，正确命名您的方法和变量，例如，

public AnimationSet AnimationSet; //poor
public AnimationSet expandAnim; //better
public AnimationSet ExpandAnimation() { //poor
public AnimationSet expand() { //better