调节屏幕亮度时，先设置当前activity亮度，再并保存为系统亮度即可。

1 onCreate()里检查系统亮度并设置seekBar：

? 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 private void screenBrightness_check() { //先关闭系统的亮度自动调节 try { if(android.provider.Settings.System.getInt(getContentResolver(),android.provider.Settings.System.SCREEN_BRIGHTNESS_MODE) == android.provider.Settings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC) { android.provider.Settings.System.putInt(getContentResolver(), android.provider.Settings.System.SCREEN_BRIGHTNESS_MODE, android.provider.Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL); } } catch (SettingNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } //获取当前亮度,获取失败则返回255 intScreenBrightness=(int)(android.provider.Settings.System.getInt(getContentResolver(), android.provider.Settings.System.SCREEN_BRIGHTNESS, 255)); //文本、进度条显示 mSeekBar_light.setProgress(intScreenBrightness); mTextView_light.setText(""+intScreenBrightness*100/255); }

2 拖动seekBar时设置当前activity亮度，并保存为系统亮度：

? 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 //屏幕亮度 private void setScreenBritness(int brightness) { //不让屏幕全暗 if(brightness<=1) { brightness=1; } //设置当前activity的屏幕亮度 WindowManager.LayoutParams lp = this.getWindow().getAttributes(); //0到1,调整亮度暗到全亮 lp.screenBrightness = Float.valueOf(brightness/255f); this.getWindow().setAttributes(lp); //保存为系统亮度方法1 android.provider.Settings.System.putInt(getContentResolver(), android.provider.Settings.System.SCREEN_BRIGHTNESS, brightness); //保存为系统亮度方法2 // Uri uri = android.provider.Settings.System.getUriFor("screen_brightness"); // android.provider.Settings.System.putInt(getContentResolver(), "screen_brightness", brightness); // // resolver.registerContentObserver(uri, true, myContentObserver); // getContentResolver().notifyChange(uri, null); //更改亮度文本显示 mTextView_light.setText(""+brightness*100/255); }