if (ANIMATE_SCREEN_LIGHTS) {

mScreenBrightness.curValue = brightness;

mScreenBrightness.animating = false;

mScreenBrightness.targetValue = -1;

}

if (ANIMATE_KEYBOARD_LIGHTS) {

mKeyboardBrightness.curValue = brightness;

mKeyboardBrightness.animating = false;

mKeyboardBrightness.targetValue = -1;

}

if (ANIMATE_BUTTON_LIGHTS) {

mButtonBrightness.curValue = brightness;

mButtonBrightness.animating = false;

mButtonBrightness.targetValue = -1;

}

}

由以上代码可知，同时设置了背光、键盘、按钮的亮度。mHardware 是硬件服务，通过该服务调用底层与设备打交道的C\C++代码，setLightBrightness_UNCHECKED原型如下：

文件：frameworks/base/services\java\com\android\server\HardwareService.java

void setLightBrightness_UNCHECKED(int light, int brightness, int brightnessMode) {

int b = brightness & 0x000000ff;

b = 0xff000000 | (b << 16) | (b << 8) | b;

setLight_native(mNativePointer, light, b, LIGHT_FLASH_NONE, 0, 0, brightnessMode);

}