Android之调节手机屏幕亮度

public class MainActivity extends Activity {
private SeekBar seekBar;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
seekBar = (SeekBar) findViewById(R.id.sb);
seekBar.setMax(255);
int normal = Settings.System.getInt(getContentResolver(),
Settings.System.SCREEN_BRIGHTNESS, 255);
seekBar.setProgress(normal);
seekBar.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {

@Override
public void onStopTrackingTouch(SeekBar seekBar) {
// TODO Auto-generated method stub

}

@Override
public void onStartTrackingTouch(SeekBar seekBar) {
// TODO Auto-generated method stub

}

//当Seekbar在滑动的时候，亮度也随着变化
@Override
public void onProgressChanged(SeekBar seekBar, int progress,
boolean fromUser) {
int tmpInt = progress;
// 当进度小于80时，设置成80，防止太黑看不见的后果。
if (tmpInt < 80) {
tmpInt = 80;
}

// 根据当前进度改变亮度
Settings.System.putInt(getContentResolver(),
Settings.System.SCREEN_BRIGHTNESS, progress);
tmpInt = Settings.System.getInt(getContentResolver(),
Settings.System.SCREEN_BRIGHTNESS, -1);
WindowManager.LayoutParams wl = getWindow().getAttributes();

float tmpFloat = (float) tmpInt / 255;
if (tmpFloat > 0 && tmpFloat <= 1) {
wl.screenBrightness = tmpFloat;
}
getWindow().setAttributes(wl);

}
});
}
}

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