public class SystemManager {

	private Context mContext;
	private static SystemManager sInstance;

	private SystemManager(final Context context) {
		mContext = context;
	}

	public static SystemManager init(final Context context) {
		if (null == sInstance) {
			sInstance = new SystemManager(context);
		}
		return sInstance;
	}

	public static SystemManager getInstance() {
		return sInstance;
	}

	// 判断是否是自动调光模式
	public boolean isAutoBrightness() {
		boolean automicBrightness = false;
		try {
			ContentResolver resolver = mContext.getContentResolver();
			automicBrightness = Settings.System.getInt(resolver,
					Settings.System.SCREEN_BRIGHTNESS_MODE) == Settings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC;
		} catch (SettingNotFoundException e) {
			e.printStackTrace();
		}
		return automicBrightness;
	}

	// 设置屏幕亮度
	public void setBrightness(Activity activity, int brightness) {
		WindowManager.LayoutParams lp = activity.getWindow().getAttributes();
		lp.screenBrightness = Float.valueOf(brightness) * (1f / 255f);
		activity.getWindow().setAttributes(lp);
	}

	// 保存屏幕亮度
	public void saveBrightness(int brightness) {
		ContentResolver resolver = mContext.getContentResolver();
		Uri uri = android.provider.Settings.System
				.getUriFor("screen_brightness");
		android.provider.Settings.System.putInt(resolver, "screen_brightness",
				brightness);
		resolver.notifyChange(uri, null);
	}

	// 开启自动调光模式
	public void startAutoBrightness() {
		ContentResolver resolver = mContext.getContentResolver();
		Settings.System.putInt(resolver,
				Settings.System.SCREEN_BRIGHTNESS_MODE,
				Settings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC);
		Uri uri = android.provider.Settings.System
				.getUriFor("screen_brightness");
		resolver.notifyChange(uri, null);
	}

	// 关闭自动调光模式
	public void stopAutoBrightness() {
		ContentResolver resolver = mContext.getContentResolver();
		Settings.System.putInt(resolver,
				Settings.System.SCREEN_BRIGHTNESS_MODE,
				Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL);
		Uri uri = android.provider.Settings.System
				.getUriFor("screen_brightness");
		resolver.notifyChange(uri, null);
	}

	// 获得当前屏幕亮度
	public int getScreenBrightness() {
		int nowBrightnessValue = http://www.mamicode.com/0;>

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