Android调节手机亮度

• 程序退出之后亮度依旧有效 ： setSystemBrightness
• 程序退出之后亮度失效 ： setCurWindowBrightness

需添加权限：

<uses-permission android:name="android.permission.WRITE_SETTINGS" /> 

public class BrightnessUtils {
    // 判断是否开启了自动亮度调节  
    public static boolean IsAutoBrightness(Context context) {
        boolean IsAutoBrightness = false;
        try {
            IsAutoBrightness = Settings.System.getInt(
                    context.getContentResolver(),
                    Settings.System.SCREEN_BRIGHTNESS_MODE) == Settings.System
                    .SCREEN_BRIGHTNESS_MODE_AUTOMATIC;
        } catch (Settings.SettingNotFoundException e) {
            e.printStackTrace();
        }
        return IsAutoBrightness;
    }
    // 获取当前屏幕的亮度  
    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;
    }
    // 设置亮度  
    // 程序退出之后亮度失效  
    public static void setCurWindowBrightness(Context context, int brightness) {
        // 如果开启自动亮度，则关闭。否则，设置了亮度值也是无效的  
        if (IsAutoBrightness(context)) {
            stopAutoBrightness(context);
        }
        // context转换为Activity  
        Activity activity = (Activity) context;
        WindowManager.LayoutParams lp = activity.getWindow().getAttributes();
        // 异常处理  
        if (brightness < 1) {
            brightness = 1;
        }
        // 异常处理  
        if (brightness > 255) {
            brightness = 255;
        }
        lp.screenBrightness = Float.valueOf(brightness) * (1f / 255f);
        activity.getWindow().setAttributes(lp);
    }
    // 设置系统亮度  
    // 程序退出之后亮度依旧有效  
    public static void setSystemBrightness(Context context, int brightness) {
        // 异常处理  
        if (brightness < 1) {
            brightness = 1;
        }
        // 异常处理  
        if (brightness > 255) {
            brightness = 255;
        }
        saveBrightness(context, brightness);
    }
    // 停止自动亮度调节  
    public static void stopAutoBrightness(Context context) {
        Settings.System.putInt(context.getContentResolver(),
                Settings.System.SCREEN_BRIGHTNESS_MODE,
                Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL);
    }
    // 开启亮度自动调节  
    public static void startAutoBrightness(Context context) {
        Settings.System.putInt(context.getContentResolver(),
                Settings.System.SCREEN_BRIGHTNESS_MODE,
                Settings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC);
    }
    // 保存亮度设置状态  
    public static void saveBrightness(Context context, int brightness) {
        Uri uri = android.provider.Settings.System
                .getUriFor("screen_brightness");
        android.provider.Settings.System.putInt(context.getContentResolver(),
                "screen_brightness", brightness);
        context.getContentResolver().notifyChange(uri, null);
    }
}