android屏幕亮度调节

package com.sensor.demo;

/**
 *  from http://apps.hi.baidu.com/share/detail/53623456
 */
import android.app.Activity;
import android.content.ContentResolver;
import android.net.Uri;
import android.provider.Settings;
import android.provider.Settings.SettingNotFoundException;
import android.util.Log;
import android.view.WindowManager;

public class BrightnessTools {
    /* Android的屏幕亮度好像在2.1+的时候提供了自动调节的功能，
     * 所以，如果当开启自动调节功能的时候， 我们进行调节好像是没有一点作用的，
     * 这点让我很是无语，结果只有进行判断，看是否开启了屏幕亮度的自动调节功能。
     */



    /** * 判断是否开启了自动亮度调节 */

    public static boolean isAutoBrightness(ContentResolver aContentResolver) {

    boolean automicBrightness = false;

    try{

    automicBrightness = Settings.System.getInt(aContentResolver,

    Settings.System.SCREEN_BRIGHTNESS_MODE) == Settings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC;

     }

    catch(SettingNotFoundException e)

    {

     e.printStackTrace();

      }

    return automicBrightness;
    }
    //然后就是要觉得当前的亮度了，这个就比较纠结了：

    /** * 获取屏幕的亮度 */

    public static int getScreenBrightness(Activity activity) {

    int nowBrightnessValue = 0;

    ContentResolver resolver = activity.getContentResolver();

    try{

    nowBrightnessValue = android.provider.Settings.System.getInt(resolver, Settings.System.SCREEN_BRIGHTNESS);

      }

     catch(Exception e) {

     e.printStackTrace();

      }

    return nowBrightnessValue;
    }

    //那如何修改屏幕的亮度呢？



    /** * 设置亮度 */

    public static void setBrightness(Activity activity, int brightness) {

     // Settings.System.putInt(activity.getContentResolver(),

    // Settings.System.SCREEN_BRIGHTNESS_MODE,

    // Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL);

    WindowManager.LayoutParams lp = activity.getWindow().getAttributes();

     lp.screenBrightness = Float.valueOf(brightness) * (1f / 255f);
     Log.d("lxy", "set  lp.screenBrightness == " + lp.screenBrightness);

     activity.getWindow().setAttributes(lp);
     }

    //那么，能设置了，但是为什么还是会出现，设置了，没反映呢？

    //嘿嘿，那是因为，开启了自动调节功能了，那如何关闭呢？这才是最重要的：

    /** * 停止自动亮度调节 */

    public static void stopAutoBrightness(Activity activity) {

     Settings.System.putInt(activity.getContentResolver(),

      Settings.System.SCREEN_BRIGHTNESS_MODE,

     Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL);
     }
    //能开启，那自然应该能关闭了哟哟，那怎么关闭呢？很简单的：

    /** * 开启亮度自动调节 *

    * @param activity */



    public static void startAutoBrightness(Activity activity) {

     Settings.System.putInt(activity.getContentResolver(),

     Settings.System.SCREEN_BRIGHTNESS_MODE,

    Settings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC);

    }

    //至此，应该说操作亮度的差不多都有了，结束！
    //哎，本来认为是应该结束了，但是悲剧得是，既然像刚才那样设置的话，只能在当前的activity中有作用，一段退出的时候，会发现毫无作用，悲剧，原来是忘记了保存了。汗！

    /** * 保存亮度设置状态 */

    public static void saveBrightness(ContentResolver resolver, int brightness) {

    Uri uri = android.provider.Settings.System.getUriFor("screen_brightness");

     android.provider.Settings.System.putInt(resolver, "screen_brightness", brightness);

    // resolver.registerContentObserver(uri, true, myContentObserver);

     resolver.notifyChange(uri, null);}
}