Android开发之调节屏幕亮度

在很多app中进入二维码显示界面时会自动调整屏幕亮度，那么如何实现调节app的屏幕亮度呢？下面我来为大家介绍：

注:调节屏幕亮度的核心思想就是对安卓系统提供的ContentProvider进行操作

---

1、声明权限
需要允许用户修改系统配置

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

2、具体操作

 /**
     * 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);
    }

好了，亮度调节差不多就这样了。