點選某個按鈕，實現另一個佈局隱藏和顯示之間的切換。

佈局檔案程式碼：

<ImageView
android:id="@+id/img_click"
android:layout_gravity="center_horizontal"
android:layout_width="80dp"
android:layout_height="wrap_content"
android:src="@mipmap/ic_open"/>
<LinearLayout
android:id="@+id/ll_show"
android:layout_width="match_parent"
android
 
:layout_height="wrap_content"
android:gravity="center"
android:orientation="vertical"
android:visibility="gone"
android:layout_marginBottom="-1dp"
android:background="#cccccc">
    <TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="我就是隱藏的內容"
android
 
:layout_marginTop="10dp"/>
</LinearLayout>

這裡說明一下，LinearLayout的marginBottom是必須的，它應該是可以避免的，但是我沒有想到好的方法，為什麼必須在下面程式碼就知道了。這個marginBottom值只在第一次時影響佈局，後面就不會再產生影響了，如果初始是隱藏狀態，這個幾乎不會有任何影響；如果初始是顯示，那麼就給他個負數的值。

很簡單的activity程式碼：

imgClick = (ImageView) findViewById(R.id.img_click);
llShow = (LinearLayout) findViewById(R.id.ll_show
 
);
imgClick.setOnClickListener(new View.OnClickListener() {
    @Override
public void onClick(View v) {
        //第一個view引數是點選後修改的物件控制元件，第二個view引數是需要隱藏顯示的佈局控制元件，第三個引數是動畫持續時間，單位毫秒
ExpandAnimation animation = new ExpandAnimation(imgClick,llShow,500);
llShow.startAnimation(animation);
}
});

關鍵的ExpandAnimation類程式碼：

/**
* This animation class is animating the expanding and reducing the size of a view.
* The animation toggles between the Expand and Reduce, depending on the current state of the view
* @author Udinic
*
*/
public class ExpandAnimation extends Animation{
	private View mAnimatedView;
	private LayoutParams mViewLayoutParams;
	private int mMarginStart, mMarginEnd;
	private boolean mIsVisibleAfter = false;
	private boolean mWasEndedAlready = false;
	
	private ImageView arrow;
	/**
	 * Initialize the animation
	 * @param view The layout we want to animate
	 * @param duration The duration of the animation, in ms
	 */
	public ExpandAnimation(View open, View view, int duration) {

		setDuration(duration);
		arrow = (ImageView) open;
		mAnimatedView = view;
		mViewLayoutParams = (LayoutParams) view.getLayoutParams();

		// if the bottom margin is 0,
		// then after the animation will end it'll be negative, and invisible.
		mIsVisibleAfter = (mViewLayoutParams.bottomMargin == 0);
		
		//根據狀態獲取動畫起始引數
		mMarginStart = mIsVisibleAfter ? 0:(0- view.getHeight());
		mMarginEnd = (mMarginStart == 0 ? (0- view.getHeight()) : 0);

		arrow.setImageResource(R.mipmap.ic_close);
		mAnimatedView.setVisibility(View.VISIBLE);
	}

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

		if (interpolatedTime < 1.0f) {

			// Calculating the new bottom margin, and setting it
			mViewLayoutParams.bottomMargin = mMarginStart
					+ (int) ((mMarginEnd - mMarginStart) * interpolatedTime);

			// Invalidating the layout, making us seeing the changes we made
			mAnimatedView.requestLayout();

			// Making sure we didn't run the ending before (it happens!)
		} else if (!mWasEndedAlready) {
			mViewLayoutParams.bottomMargin = mMarginEnd;
			mAnimatedView.requestLayout();

			if (mIsVisibleAfter) {
				mAnimatedView.setVisibility(View.GONE);
				arrow.setImageResource(R.mipmap.ic_open);
			}
			mWasEndedAlready = true;
		}
	}
}

這個使用時資料已有的情況，如果是展開後加載資料，這個不適用了，也許改改就行了，也許不行。具體看需求，完事收工！