分享一个Android Expand Collapse的动画

通过Animation实现：

public class ExpandCollapseAnimation extends Animation {
	private View mAnimatedView;
	private int mEndHeight;
	private int mType;
	public final static int COLLAPSE = 1;
	public final static int EXPAND = 0;
	private LinearLayout.LayoutParams mLayoutParams;

	/**
	 * Initializes expand collapse animation, has two types, collapse (1) and expand (0).
	 * @param view The view to animate
	 * @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 ExpandCollapseAnimation(View view, int type) {

		mAnimatedView = view;
		mEndHeight = mAnimatedView.getMeasuredHeight();
		mLayoutParams = ((LinearLayout.LayoutParams) view.getLayoutParams());
		mType = type;
		if(mType == EXPAND) {

			mLayoutParams.bottomMargin = -mEndHeight;
		} else {

			mLayoutParams.bottomMargin = 0;
		}
		view.setVisibility(View.VISIBLE);
	}

	@Override
	protected void applyTransformation(float interpolatedTime, Transformation t) {

		super.applyTransformation(interpolatedTime, t);
		if (interpolatedTime < 1.0f) {
			if(mType == EXPAND) {
				mLayoutParams.bottomMargin =  -mEndHeight + (int) (mEndHeight * interpolatedTime);
			} else {
				mLayoutParams.bottomMargin = - (int) (mEndHeight * interpolatedTime);
			}
			Log.d("ExpandCollapseAnimation", "anim height " + mLayoutParams.bottomMargin);
			mAnimatedView.requestLayout();
		} else {
			if(mType == EXPAND) {
				mLayoutParams.bottomMargin = 0;
				mAnimatedView.requestLayout();
			} else {
				mLayoutParams.bottomMargin = -mEndHeight;
				mAnimatedView.setVisibility(View.GONE);
				mAnimatedView.requestLayout();
			}
		}
	}
}

第一种方式详细请看：https://github.com/tjerkw/Android-SlideExpandableListView

第二种方式是自己通过Animator实现也行：

public class ExpandCollapseAnimation {
	public static ValueAnimator ExpandAnimation(final View view, int start,
			final int end) {
		ValueAnimator animator = ValueAnimator.ofInt(start, end);
		animator.addUpdateListener(new AnimatorUpdateListener() {

			@Override
			public void onAnimationUpdate(ValueAnimator arg0) {
				// TODO Auto-generated method stub
				//通过更改height也可以，但是有些os不行，还不知道什么原因
				LinearLayout.LayoutParams params = (LayoutParams) view.getLayoutParams();
				params.bottomMargin = (int) arg0.getAnimatedValue() - end;
				view.requestLayout();
			}
		});
		animator.addListener(new AnimatorListener() {

			@Override
			public void onAnimationStart(Animator arg0) {
				// TODO Auto-generated method stub
				view.setVisibility(View.VISIBLE);
			}

			@Override
			public void onAnimationRepeat(Animator arg0) {
				// TODO Auto-generated method stub

			}

			@Override
			public void onAnimationEnd(Animator arg0) {
				// TODO Auto-generated method stub

			}

			@Override
			public void onAnimationCancel(Animator arg0) {
				// TODO Auto-generated method stub

			}
		});
		return animator;
	}

	public static ValueAnimator CollapseAnimation(final View view, final int start,
			int end) {
		ValueAnimator animator = ValueAnimator.ofInt(start, end);
		animator.addUpdateListener(new AnimatorUpdateListener() {

			@Override
			public void onAnimationUpdate(ValueAnimator arg0) {
				// TODO Auto-generated method stub
				LinearLayout.LayoutParams params = (LayoutParams) view.getLayoutParams();
				params.bottomMargin = (int) arg0.getAnimatedValue() - start;
				view.requestLayout();
			}
		});
		animator.addListener(new AnimatorListener() {

			@Override
			public void onAnimationStart(Animator arg0) {
				// TODO Auto-generated method stub
			}

			@Override
			public void onAnimationRepeat(Animator arg0) {
				// TODO Auto-generated method stub

			}

			@Override
			public void onAnimationEnd(Animator arg0) {
				// TODO Auto-generated method stub
				view.setVisibility(View.GONE);
			}

			@Override
			public void onAnimationCancel(Animator arg0) {
				// TODO Auto-generated method stub

			}
		});
		return animator;
	}
}