Android9.0手动亮度调节流程_android 9 改变屏幕亮度-优快云博客

本文链接：https://blog.youkuaiyun.com/wolfnx/article/details/104911912

本文详细解析了Android系统中亮度调节的内部流程，从BrightnessController到DisplayManager，再到HAL层的调用过程，覆盖rk3328平台及Android9.0版本。

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前言

最近在改平台的亮度设置，顺便整理一下亮度调节的过程，使他人能方便理解亮度流程。

Kernel: v4.4.179
Device: rk3328
Platform Version: Android 9.0

流程如下

frameworks/base/packages/SystemUI/src/com/android/systemui/settings/BrightnessController.java

DisplayManager.java

 public void setTemporaryBrightness(int brightness) {
		 mGlobal.setTemporaryBrightness(brightness);
 }

DisplayManagerGlobal.java

 public void setTemporaryBrightness(int brightness) {
 	try {
     	mDm.setTemporaryBrightness(brightness);
 	} catch (RemoteException ex) {
     	throw ex.rethrowFromSystemServer();
 	}
 }

DisplayManagerService.java

 public void setTemporaryBrightness(int brightness) {
 ...
   	mDisplayPowerController.setTemporaryBrightness(brightness);
 ...
 }

DisplayPowerController.java

 public void setTemporaryBrightness(int brightness) {
 	Message msg = mHandler.obtainMessage(MSG_SET_TEMPORARY_BRIGHTNESS,
         brightness, 0 /*unused*/);
 		msg.sendToTarget();
 }
 ...
 private void updatePowerState() {
 	//此方法比较长，里面有大量的判断，下面只写关键语句
 	...
 	animateScreenBrightness(brightness, 0);
 	...
 }
 ...
 private void animateScreenBrightness(int target, int rate) {
 	//这一句就是关键的设置语句
 	if (mScreenBrightnessRampAnimator.animateTo(target, rate)) {
  	}
 }

下面的就不太好跟了，直接贴图 RampAnimator.java

DisplayPowerState.java

 setScreenBrightness(int brightness){...}
 scheduleScreenUpdate() {...}
 postScreenUpdateThreadSafe(){...}
 Runnable mScreenUpdateRunnable = new Runnable() {
 	...
 	mPhotonicModulator.setState(mScreenState, brightness)
 	...
 }