以编程方式改变android中的亮度

Question

在android studio中编写用于以编程方式更改亮度的代码时，setContentView，getContentResolver，ChangeBright，findViewById和getWindow都是红色的。它说不能解决方法。为什么会这样？

private SeekBar brightbar;
private int brightness;
private ContentResolver Conresolver;
private Window window;

@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_tab3);

    brightbar = (SeekBar) findViewById(R.id.ChangeBright);


    Conresolver = getContentResolver();

    window = getWindow();


    brightbar.setMax(255);

    brightbar.setKeyProgressIncrement(1);

    try
    {

        brightness = System.getInt(Conresolver, System.SCREEN_BRIGHTNESS);
    }
    catch (SettingNotFoundException e)
    {

        Log.e("Error", "Cannot access system brightness");
        e.printStackTrace();
    }


    brightbar.setProgress(brightness);


    brightbar.setOnSeekBarChangeListener(new OnSeekBarChangeListener()
    {
        public void onStopTrackingTouch(SeekBar seekBar)
        {
            System.putInt(Conresolver, System.SCREEN_BRIGHTNESS, brightness);

            LayoutParams layoutpars = window.getAttributes();

            layoutpars.screenBrightness = brightness / (float)255;

            window.setAttributes(layoutpars);
        }

        public void onStartTrackingTouch(SeekBar seekBar)
        {

        }

        public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser)
        {

            if(progress<=20)
            {

                brightness=20;
            }
            else
            {

                brightness = progress;
            }

Answer 1

您确定您的代码是否扩展了活动？