Android开发实现调节屏幕亮度功能

/**
* 判断是否开启了自动亮度调节
*/
public static boolean isAutoBrightness(Context context) {
  ContentResolver resolver = context.getContentResolver();
  boolean automicBrightness = false;
  try {
   automicBrightness = Settings.System.getInt(resolver,
     Settings.System.SCREEN_BRIGHTNESS_MODE) == Settings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC;
  } catch (Settings.SettingNotFoundException e) {
   e.printStackTrace();
  }
  return automicBrightness;
}
/**
* 获取屏幕的亮度
*/
public static int getScreenBrightness(Context context) {
  int nowBrightnessValue = 0;
  ContentResolver resolver = context.getContentResolver();
  try {
   nowBrightnessValue = android.provider.Settings.System.getInt(resolver, Settings.System.SCREEN_BRIGHTNESS);
  } catch (Exception e) {
   e.printStackTrace();
  }
  return nowBrightnessValue;
}
/**
* 设置当前Activity显示时的亮度
* 屏幕亮度最大数值一般为255，各款手机有所不同
* screenBrightness 的取值范围在[0,1]之间
*/
public static void setBrightness(Activity activity, int brightness) {
  WindowManager.LayoutParams lp = activity.getWindow().getAttributes();
  lp.screenBrightness = Float.valueOf(brightness) * (1f / 255f);
  activity.getWindow().setAttributes(lp);
}
/**
* 开启关闭自动亮度调节
*/
public static boolean autoBrightness(Context activity, boolean flag) {
  int value = 0;
  if (flag) {
   value = Settings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC; //开启
  } else {
   value = Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL;//关闭
  }
  return Settings.System.putInt(activity.getContentResolver(),
    Settings.System.SCREEN_BRIGHTNESS_MODE,
    value);
}
/**
* 保存亮度设置状态，退出app也能保持设置状态
*/
public static void saveBrightness(Context context, int brightness) {
  ContentResolver resolver = context.getContentResolver();
  Uri uri = android.provider.Settings.System.getUriFor(Settings.System.SCREEN_BRIGHTNESS);
  android.provider.Settings.System.putInt(resolver, Settings.System.SCREEN_BRIGHTNESS, brightness);
  resolver.notifyChange(uri, null);
}