1、背景
【操作步骤】负一屏界面，语音输入：“中文模式/英文模式”
【预期结果】显示正常
【实际结果】
会闪现一下负一屏下层的文字
【发生概率】必现
systemui下拉负一屏界面，通过语音输入：“中文模式/英文模式”，会闪现一下负一屏下层的画面。
2、分析过程
通过逐帧播放视频，我们猜测，bug中的闪屏是指负一屏以下的layer的渐变的动画。
接下来通过动画的调试手段来分析定位问题。
2.1 知识积累：
开发者选项中有三个动画因子
“Window animation scale” :窗口动画缩放
“Transition animation scale” :过渡动画缩放
“Animator duration scale” :动画程序时长缩放
调整动画时长：
adb shell settings get global window_animation_scale
adb shell settings get global transition_animation_scale
adb shell settings get global animator_duration_scale
adb shell settings put global window_animation_scale 10
adb shell settings put global transition_animation_scale 10
adb shell settings put global animator_duration_scale 10
修改白天、黑夜模式：
白天模式 adb shell “su 0 cmd uimode night no”
黑夜模式 adb shell “su 0 cmd uimode night yes”
通过分别设置，发现问题中的现象步骤一，能够清晰的看出来是有一个渐变的动画；
步骤二，现象消失。这能够充分说明，这个问题与android动画有关，需要通过debug animation来定位问题。
adb shell settings put global transition_animation_scale 20
adb shell settings put global transition_animation_scale 0
2.2 如何模拟语言切换中英文：
写一个demo apk，通过广播控制语言切换，切换语言的部分代码如下：
try {Log.d(TAG, "setLanguage: " + languageCode);Locale locale = new Locale(languageCode);Log.d(TAG, "setAppLanguage() start " + locale.toString());IActivityManager am = ActivityManagerNative.getDefault();Configuration config = am.getConfiguration();//config.locale = locale;config.setLocales(new LocaleList(locale));config.userSetLocale = true;am.updatePersistentConfiguration(config);} catch (android.os.RemoteException e) {e.printStackTrace();}
adb shell am broadcast -a android.intent.action.CHANG_LANGUAGE --es code “zh”
adb shell am broadcast -a android.intent.action.CHANG_LANGUAGE --es code “en”
2.3 Android Framework 调试Animation动画的方法
（1）8155（android 11）定位animation问题，如何开启log：
WindowManagerDebugConfig
static final boolean DEBUG_ANIM = false; 设置为true
(2) 如何找到具体是受哪个Animation的影响，导致的问题：
SurfaceAnimator
void startAnimation(Transaction t, AnimationAdapter anim, boolean hidden,@AnimationType int type,@Nullable OnAnimationFinishedCallback animationFinishedCallback,@Nullable SurfaceFreezer freezer) {Slog.w(TAG, "startAnimation, anim = " + anim + ", hidden = " + hidden + ", t = " + t + ", freezer" + freezer + ", mAnimatable = " + mAnimatable+ ", sc = " + mAnimatable.getSurfaceControl());cancelAnimation(t, true /* restarting */, true /* forwardCancel */);mAnimation = anim;mAnimationType = type;mAnimationFinishedCallback = animationFinishedCallback;final SurfaceControl surface = mAnimatable.getSurfaceControl();if (surface == null) {Slog.w(TAG, "Unable to start animation, surface is null or no children.");cancelAnimation();return;}if (mAnimatable != null && (mAnimatable.toString().contains("SimpleSurfaceAnimatable")&& surface.toString().contains("RotationLayer"))) {Slog.w(TAG, "----startAnimation exit-----------", new Throwable("xxxx"));//Slog.w(TAG, "----startAnimation exit-----------");//cancelAnimation();// return;}mLeash = freezer != null ? freezer.takeLeashForAnimation() : null;if (mLeash == null) {mLeash = createAnimationLeash(mAnimatable, surface, t, type,mAnimatable.getSurfaceWidth(), mAnimatable.getSurfaceHeight(), 0 /* x */,0 /* y */, hidden, mService.mTransactionFactory);mAnimatable.onAnimationLeashCreated(t, mLeash);}mAnimatable.onLeashAnimationStarting(t, mLeash);if (mAnimationStartDelayed) {if (DEBUG_ANIM) Slog.i(TAG, "Animation start delayed");return;}mAnimation.startAnimation(mLeash, t, type, mInnerAnimationFinishedCallback);}
行 78189: 12-31 11:13:59.970 1223 4645 W WindowManager: startAnimation, anim = com.android.server.wm.InsetsSourceProvider$ControlAdapter@896c73d, hidden = true, t = android.view.SurfaceControl$Transaction@e68b403, freezercom.android.server.wm.SurfaceFreezer@ffd88a7, mAnimatable = Window{2bfa2a8 u0 InputMethod}, sc = Surface(name=2bfa2a8 InputMethod)/@0x6c04154行 78771: 12-31 11:14:00.247 1223 1513 W WindowManager: startAnimation, anim = com.android.server.wm.InsetsSourceProvider$ControlAdapter@917a8b1, hidden = false, t = android.view.SurfaceControl$Transaction@e68b403, freezercom.android.server.wm.SurfaceFreezer@6b73875, mAnimatable = Window{c17a926 u0 BottomCarSystemBar}, sc = Surface(name=c17a926 BottomCarSystemBar)/@0xeb4e00a行 78795: 12-31 11:14:00.258 1223 1513 W WindowManager: startAnimation, anim = com.android.server.wm.InsetsSourceProvider$ControlAdapter@a2a9d7f, hidden = false, t = android.view.SurfaceControl$Transaction@e68b403, freezercom.android.server.wm.SurfaceFreezer@6bfbf80, mAnimatable = Window{8ddd15a u0 TopCarSystemBar}, sc = Surface(name=8ddd15a TopCarSystemBar)/@0x8fdb9b9行 79249: 12-31 11:14:00.769 1223 1513 W WindowManager: startAnimation, anim = com.android.server.wm.LocalAnimationAdapter@c3d4ea4, hidden = false, t = android.view.SurfaceControl$Transaction@e68b403, freezernull, mAnimatable = com.android.server.wm.SimpleSurfaceAnimatable@45c3937, sc = Surface(name=mWindowContainers)/@0x24aa028行 79254: 12-31 11:14:00.769 1223 1513 W WindowManager: startAnimation, anim = com.android.server.wm.LocalAnimationAdapter@a3131d3, hidden = false, t = android.view.SurfaceControl$Transaction@e68b403, freezernull, mAnimatable = com.android.server.wm.SimpleSurfaceAnimatable@617ffc2, sc = Surface(name=RotationLayer)/@0x52b110
一次语言切换，会触发5次动画，一步一步定位是哪个动画导致的问题。
12-31 11:14:00.770 1223 1513 W WindowManager: ----startAnimation exit-----------
12-31 11:14:00.770 1223 1513 W WindowManager: java.lang.Throwable: xxxx
12-31 11:14:00.770 1223 1513 W WindowManager: at com.android.server.wm.SurfaceAnimator.startAnimation(SurfaceAnimator.java:153)
12-31 11:14:00.770 1223 1513 W WindowManager: at com.android.server.wm.SurfaceAnimator.startAnimation(SurfaceAnimator.java:177)
12-31 11:14:00.770 1223 1513 W WindowManager: at com.android.server.wm.SurfaceAnimator.startAnimation(SurfaceAnimator.java:182)
12-31 11:14:00.770 1223 1513 W WindowManager: at com.android.server.wm.ScreenRotationAnimation$SurfaceRotationAnimationController.startAnimation(ScreenRotationAnimation.java:720)
12-31 11:14:00.770 1223 1513 W WindowManager: at com.android.server.wm.ScreenRotationAnimation$SurfaceRotationAnimationController.startScreenshotRotationAnimation(ScreenRotationAnimation.java:634)
12-31 11:14:00.770 1223 1513 W WindowManager: at com.android.server.wm.ScreenRotationAnimation$SurfaceRotationAnimationController.startScreenRotationAnimation(ScreenRotationAnimation.java:585)
12-31 11:14:00.770 1223 1513 W WindowManager: at com.android.server.wm.ScreenRotationAnimation.startAnimation(ScreenRotationAnimation.java:438)
12-31 11:14:00.770 1223 1513 W WindowManager: at com.android.server.wm.ScreenRotationAnimation.dismiss(ScreenRotationAnimation.java:456)
12-31 11:14:00.770 1223 1513 W WindowManager: at com.android.server.wm.WindowManagerService.stopFreezingDisplayLocked(WindowManagerService.java:5969)
12-31 11:14:00.770 1223 1513 W WindowManager: at com.android.server.wm.RootWindowContainer.performSurfacePlacementNoTrace(RootWindowContainer.java:922)
12-31 11:14:00.770 1223 1513 W WindowManager: at com.android.server.wm.RootWindowContainer.performSurfacePlacement(RootWindowContainer.java:819)
12-31 11:14:00.770 1223 1513 W WindowManager: at com.android.server.wm.WindowSurfacePlacer.performSurfacePlacementLoop(WindowSurfacePlacer.java:178)
12-31 11:14:00.770 1223 1513 W WindowManager: at com.android.server.wm.WindowSurfacePlacer.performSurfacePlacement(WindowSurfacePlacer.java:127)
12-31 11:14:00.770 1223 1513 W WindowManager: at com.android.server.wm.WindowSurfacePlacer.performSurfacePlacement(WindowSurfacePlacer.java:116)
12-31 11:14:00.770 1223 1513 W WindowManager: at com.android.server.wm.WindowSurfacePlacer$Traverser.run(WindowSurfacePlacer.java:58)
12-31 11:14:00.770 1223 1513 W WindowManager: at android.os.Handler.handleCallback(Handler.java:938)
12-31 11:14:00.770 1223 1513 W WindowManager: at android.os.Handler.dispatchMessage(Handler.java:99)
12-31 11:14:00.770 1223 1513 W WindowManager: at android.os.Looper.loop(Looper.java:223)
12-31 11:14:00.770 1223 1513 W WindowManager: at android.os.HandlerThread.run(HandlerThread.java:67)
12-31 11:14:00.770 1223 1513 W WindowManager: at com.android.server.ServiceThread.run(ServiceThread.java:44)
3、解决方案
关闭动画解决该问题：（车载项目没有rotation的动作，可以这样做，但是手机或者平板不能这样修改。）
