Android WindowManager及其動畫問題

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本：1.0 日期：2014.8.16 2014.8.23 2014.8.26著作權：© 2014 kince 轉載註明出處  一、概述    開發中發現在WindowManager上像在Activity中使用動畫效果無效，比如下面的代碼：

        ImageView iv = new ImageView(this);        iv.setImageResource(R.drawable.ic_launcher);        TranslateAnimation animation = new TranslateAnimation(                Animation.ABSOLUTE, 20, Animation.ABSOLUTE, 300,                Animation.ABSOLUTE, 100, Animation.ABSOLUTE, 400);        animation.setDuration(1000);        animation.setFillAfter(false);        iv.setAnimation(animation);        WindowManager mWindowManager = (WindowManager) this                .getSystemService(Context.WINDOW_SERVICE);        WindowManager.LayoutParams mLayoutParams = new WindowManager.LayoutParams();        mLayoutParams.x = 20;        mLayoutParams.y = 100;        mLayoutParams.height = WindowManager.LayoutParams.WRAP_CONTENT;        mLayoutParams.width = WindowManager.LayoutParams.WRAP_CONTENT;        mLayoutParams.gravity = Gravity.TOP;        mLayoutParams.flags = WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE                | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE                | WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON                | WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN;        mWindowManager.addView(iv, mLayoutParams);        animation.start();

二、分析  為什麼會不執行動畫呢，原因在於：the view which is going to be animated must not be directly added to the top window, because top window of android is not a real ViewGroup. so the view must be added to a ViewGroup like FrameLayout first and then this ViewGroup be added to the top window.意思是說動畫執行的條件是不能直接添加到最頂層的Window，而是需要一個容器。比如，在xml中定義的控制項就可以使用動畫。  後來發現一種解決方案是WindowManager.LayoutParams有一個動畫屬性：windowAnimations，可以這樣使用

   lp = new WindowManager.LayoutParams(LayoutParams.WRAP_CONTENT,                    LayoutParams.WRAP_CONTENT,                    WindowManager.LayoutParams.TYPE_PHONE,                    WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE                              | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE                              | WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE,                     PixelFormat.RGBA_8888);          lp.gravity = Gravity.LEFT |Gravity.TOP;          lp.windowAnimations = R.style.anim_view;//動畫          wm = (WindowManager) getSystemService(Context.WINDOW_SERVICE);          wm.addView(view, lp);

  但是，這是對整個View的一個動畫，而不是View中某個控制項的動畫。而且，使用的時候需要在View狀態改變的時候才會出現動畫效果。比如消失/出現的時候才會有動畫效果。因此這個方案也是行不通的。  既然WindowManager不是一個ViewGroup，那麼就構造一個容器來裝載WindowManager，可以如下：

/****/package com.kince.apus.widget;import com.kince.apus.R;import android.animation.Animator;import android.animation.Animator.AnimatorListener;import android.animation.AnimatorSet;import android.animation.ObjectAnimator;import android.content.Context;import android.graphics.PixelFormat;import android.os.Handler;import android.util.AttributeSet;import android.view.LayoutInflater;import android.view.View;import android.view.WindowManager;import android.widget.FrameLayout;import android.widget.ImageView;import android.widget.TextView;/*** @author kince* @category Windowmanager在Layout中的應用***/public class GuideLayout extends FrameLayout {     private WindowManager wManager;     private WindowManager.LayoutParams wmParams;     private View addView;     private TextView mTextView;     private ImageView mImageView;     private boolean isAddView;     private AnimatorSet mShowAnimatorSet, mHideAnimatorSet;     private Handler mHandler = new Handler() {          public void handleMessage(android.os.Message msg) {               super.handleMessage(msg);               switch (msg.what) {               case 1:                    showAnimator();                    break;               default:                    break;               }          };     };     /**     * @param context     */     public GuideLayout(Context context) {          this(context, null);          // TODO Auto-generated constructor stub     }     /**     * @param context     * @param attrs     */     public GuideLayout(Context context, AttributeSet attrs) {          this(context, attrs, 0);          // TODO Auto-generated constructor stub     }     /**     * @param context     * @param attrs     * @param defStyle     */     public GuideLayout(Context context, AttributeSet attrs, int defStyle) {          super(context, attrs, defStyle);          addView = LayoutInflater.from(context).inflate(R.layout.guide_layout,                    this);          mTextView = (TextView) addView.findViewById(R.id.tv);          mImageView = (ImageView) addView.findViewById(R.id.iv);          mTextView.setVisibility(View.GONE);          mImageView.setVisibility(View.GONE);          setAnimator();          getWindowManager(context);     }     /**     * @category 執行個體化WindowManager 初次類比位置時候使用     * @param context     */     private void getWindowManager(final Context context) {          wManager = (WindowManager) context.getApplicationContext()                    .getSystemService(Context.WINDOW_SERVICE);          wmParams = new WindowManager.LayoutParams();          wmParams.type = WindowManager.LayoutParams.TYPE_SYSTEM_ALERT;          wmParams.format = PixelFormat.TRANSPARENT;          wmParams.flags = WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL                    | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE                    | WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE;          wmParams.gravity = 17;          wmParams.width = WindowManager.LayoutParams.MATCH_PARENT;          wmParams.height = WindowManager.LayoutParams.MATCH_PARENT;     }     private void setAnimator() {          mShowAnimatorSet = new AnimatorSet();          Animator[] showAnimator = new Animator[2];          showAnimator[0] = ObjectAnimator.ofFloat(mTextView, "alpha",                    new float[] { 0.0F, 1.0F });          showAnimator[1] = ObjectAnimator.ofFloat(mImageView, "alpha",                    new float[] { 0.0F, 1.0F });          mShowAnimatorSet.playTogether(showAnimator);          mShowAnimatorSet.setDuration(1500l);          mHideAnimatorSet = new AnimatorSet();          Animator[] hideAnimator = new Animator[2];          hideAnimator[0] = ObjectAnimator.ofFloat(mTextView, "alpha",                    new float[] { 1.0F, 0.0F });          hideAnimator[1] = ObjectAnimator.ofFloat(mImageView, "alpha",                    new float[] { 1.0F, 0.0F });          mHideAnimatorSet.playTogether(hideAnimator);          mHideAnimatorSet.setDuration(1500l);     }     public void showAnimator() {          mTextView.setVisibility(View.VISIBLE);          mImageView.setVisibility(View.VISIBLE);          mShowAnimatorSet.start();          isAddView=true;     }     public void hideAnimator() {          mHideAnimatorSet.start();          mHideAnimatorSet.addListener(new AnimatorListener() {               @Override               public void onAnimationStart(Animator animation) {                    // TODO Auto-generated method stub               }               @Override               public void onAnimationRepeat(Animator animation) {                    // TODO Auto-generated method stub               }               @Override               public void onAnimationEnd(Animator animation) {                    // TODO Auto-generated method stub                    mTextView.setVisibility(View.INVISIBLE);                    mImageView.setVisibility(View.INVISIBLE);               }               @Override               public void onAnimationCancel(Animator animation) {                    // TODO Auto-generated method stub               }          });     }     public void sendMessage() {          if (isAddView) {               wManager.removeView(this);               mHandler.removeMessages(1);               isAddView=false;          }          mHandler.sendEmptyMessage(1);          wManager.addView(this, wmParams);     }}

  這樣一來，就可以實現在WindowManager上的動畫效果了。其實，造成這種現象的原因在於對Android API以及其體系的理解不夠深刻。忽略了動畫執行所需要的基本條件，影射的問題就是考慮問題不夠全面。所以，不論開發哪種功能，使用哪個API，前期的規劃、調研很重要。知己知彼，僅此而已。

Android WindowManager及其動畫問題