从零开始：Java实现Windows屏幕亮度自动调节的步骤详解

本部分代码地址：

屏幕亮度的知识点

• Android系统的屏幕亮度取值范围是0-255，数据是int型；
• 屏幕亮度的模式有两种，如下：

设置屏幕亮度的常见方法如下 ：

• 获取当前屏幕亮度：获取到的是0-255范围内的值；

privateintgetCurrentScreenBrightness(Context context){int currentBrightness =0;
    ContentResolver contentResolver = context.getContentResolver();try{
        currentBrightness = Settings.System.getInt(contentResolver, Settings.System.SCREEN_BRIGHTNESS);}catch(Settings.SettingNotFoundException e){
        e.printStackTrace();}return currentBrightness;}

• 获取当前屏幕亮度模式：返回值是0（手动调节模式）或者1（自动调节模式）；

privateintgetCurrentScreenBrightnessMode(Context context){int screenBrightnessMode =0;
    ContentResolver contentResolver = context.getContentResolver();try{
        screenBrightnessMode = Settings.System.getInt(contentResolver, Settings.System.SCREEN_BRIGHTNESS_MODE);}catch(Settings.SettingNotFoundException e){
        e.printStackTrace();}return screenBrightnessMode;}

• 设置屏幕调节模式：需要先获取android.permission.WRITE_SETTINGS这个权限，然后才能设置屏幕调节模式，否则会报错：was not granted this permission: android.permission.WRITE_SETTINGS。0-手动调节模式，1-自动调节模式；

//清单文件中申请权限；<uses-permission android:name="android.permission.WRITE_SETTINGS"/>//6.0以后需要动态申请系统的权限；privatevoidrequestPermission(int mode){if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.M){if(!Settings.System.canWrite(this)){
            Intent intent =newIntent(android.provider.Settings.ACTION_MANAGE_WRITE_SETTINGS);
            intent.setData(Uri.parse("package:"+this.getPackageName()));
            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);this.startActivity(intent);}else{//有了权限，具体的操作;setScreenMode(this, mode);}}}//具体的操作屏幕亮度；privatevoidsetScreenMode(Context context,int mode){
    ContentResolver contentResolver =getContentResolver();
    Settings.System.putInt(contentResolver, Settings.System.SCREEN_BRIGHTNESS_MODE, mode);}

• 设置当前页面的屏幕亮度，但是并不会影响系统的屏幕亮度，也就是说设置了当前页面的屏幕亮度，系统的屏幕亮度还是先前的数值，需要申请权限android.permission.CHANGE_CONFIGURATION，否则不会执行调节屏幕亮度；

////清单文件中申请权限；<uses-permission android:name="android.permission.CHANGE_CONFIGURATION"/>privatevoidsetCurrentBrightness(Activity activity,int brightness){
    WindowManager.LayoutParams layoutParams = activity.getWindow().getAttributes();
    layoutParams.screenBrightness = Float.valueOf(brightness)*(1f/255f);
    activity.getWindow().setAttributes(layoutParams);}

• 设置系统的屏幕亮度，直接影响系统的屏幕亮度。和设置亮度模式一样，需要先获取android.permission.WRITE_SETTINGS这个权限，然后才能设置屏幕调节模式，否则会报错：was not granted this permission: android.permission.WRITE_SETTINGS。；

//还是需要在6.0以上的手机上申请android.permission.WRITE_SETTINGS权限；if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.M){if(!Settings.System.canWrite(this)){
        Intent intent =newIntent(android.provider.Settings.ACTION_MANAGE_WRITE_SETTINGS);
        intent.setData(Uri.parse("package:"+this.getPackageName()));
        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);this.startActivity(intent);}else{//有了权限，具体的操作;setSystemBrightness(this,200);}}//具体设置系统的屏幕亮度；                privatevoidsetSystemBrightness(Context context,int brightness){
    ContentResolver contentResolver = context.getContentResolver();
    Uri uri = android.provider.Settings.System.getUriFor(Settings.System.SCREEN_BRIGHTNESS);
    android.provider.Settings.System.putInt(contentResolver,Settings.System.SCREEN_BRIGHTNESS,brightness);
    contentResolver.notifyChange(uri,null);}

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