Android9.0手动亮度调节流程

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)
    ...
}