PopupWindow 动画

1.PopupWindow 简介

首先看android.widget.PopupWindow.java源码注释：

/*** <p>A popup window that can be used to display an arbitrary view. The popup* window is a floating container that appears on top of the current* activity.</p>* * @see android.widget.AutoCompleteTextView* @see android.widget.Spinner*/

PopupWindow是一个容器，用来存放任意view然后显示在当前activity的顶部。

再看PopupWindow是怎么显示的，调用显示的方法是

  public void showAtLocation(IBinder token, int gravity, int x, int y) {if (isShowing() || mContentView == null) {return;}unregisterForScrollChanged();mIsShowing = true;mIsDropdown = false;WindowManager.LayoutParams p = createPopupLayout(token);p.windowAnimations = computeAnimationResource();//计算当前赋值的窗口动画资源preparePopup(p);if (gravity == Gravity.NO_GRAVITY) {gravity = Gravity.TOP | Gravity.START;}p.gravity = gravity;p.x = x;p.y = y;if (mHeightMode < 0) p.height = mLastHeight = mHeightMode;if (mWidthMode < 0) p.width = mLastWidth = mWidthMode;invokePopup(p);}

在上面方法里面，WindowManager会通过方法computeAnimationResource()初始化PopupWindow所需要的动画资源:

 private int computeAnimationResource() {if (mAnimationStyle == -1) {if (mIsDropdown) {return mAboveAnchor? com.android.internal.R.style.Animation_DropDownUp: com.android.internal.R.style.Animation_DropDownDown;//系统默认的动画资源}return 0;}return mAnimationStyle;}

由此可以看到PopupWindow是通过values/style.xml来配置动画效果的。这点和View是不同的，View的动画资源直接在values/anim/下配置。

PopupWindow本质上是通过WindowManager创建的一个window,然后在window里面放入了所需要显示的view，如果需要配置窗口级别的动画可以采用类似方式。

为此，PopupWindow提供了公开的设置动画资源的方法setAnimationStyle。

2.PopupWindow示例代码

附上示例：

public class PopupWindowAnimationActivity extends Activity implements OnClickListener{ListPopupWindow mListPopupwindow;Button btn;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_popupwindow_animation);btn = (Button) this.findViewById(R.id.showPopupwindow);btn.setOnClickListener(this);mListPopupwindow = new ListPopupWindow(this);mListPopupwindow.setAnimationStyle(R.style.PopupAnimation);mListPopupwindow.setAnchorView(btn);String [] str = new String[]{"test1","test2"};ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,android.R.layout.simple_expandable_list_item_1);adapter.addAll(str);mListPopupwindow.setAdapter(adapter);mListPopupwindow.setWidth(300);mListPopupwindow.setHeight(LayoutParams.WRAP_CONTENT);mListPopupwindow.setBackgroundDrawable(this.getResources().getDrawable(R.drawable.more_menu_popup_bg));}@Overrideprotected void onPause() {// TODO Auto-generated method stubsuper.onPause();}@Overrideprotected void onResume() {// TODO Auto-generated method stubsuper.onResume();}@Overrideprotected void onStop() {// TODO Auto-generated method stubsuper.onStop();}@Overridepublic void onClick(View arg0) {// TODO Auto-generated method stubint id = arg0.getId();if(id == R.id.showPopupwindow){mListPopupwindow.show();}}

<style name="PopupAnimation" parent="android:Animation"><item name="android:windowEnterAnimation">@anim/ani_in</item><item name="android:windowExitAnimation">@anim/ani_out</item></style>

3.示例下载

点击打开链接 https://github.com/zhhp1121/AndroidAnimationTeam.git