Android 2.2：调整屏幕亮度

Question

    public void SetBright(float value) 
{
    Window mywindow = getWindow();

    WindowManager.LayoutParams lp = mywindow.getAttributes();

            lp.screenBrightness = value;

            mywindow.setAttributes(lp);
}

我想调整屏幕亮度。 但是当我尝试使用这种方法时没有任何反应。 可能是因为我使用KEEP_SCREEN_ON标志？

Answer 1

确保在设置屏幕亮度之前未启用“自动亮度”。 如果您使用的是Android 2.2或更高版本的SDK，则可以在“设置”>“显示”中手动执行此操作或使用代码。

就像是：

int brightnessMode = Settings.System.getInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS_MODE);
if (brightnessMode == Settings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC) {
    Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS_MODE, Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL);
}

WindowManager.LayoutParams layoutParams = getWindow().getAttributes();
layoutParams.screenBrightness = 0.5F; // set 50% brightness
getWindow().setAttributes(layoutParams);

确保该值介于0.0F和1.0F之间。 值-1.0F使用首选项中存储的默认亮度。 根据文档“值小于0，默认值，意味着使用首选屏幕亮度.0到1调整亮度从暗到亮。”

Answer 2

使用搜索条调整亮度：

公共类AndroidBrightnessActivity扩展Activity {

private SeekBar brightbar;
private int brightness;
private ContentResolver cResolver;
private Window window;
TextView txtPerc;
@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    brightbar = (SeekBar) findViewById(R.id.brightbar);
    txtPerc = (TextView) findViewById(R.id.txtPercentage);
    cResolver = getContentResolver();
    window = getWindow();
    brightbar.setMax(255);
    brightbar.setKeyProgressIncrement(1);

    try
    {
        brightness = System.getInt(cResolver, 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(cResolver,System.SCREEN_BRIGHTNESS,brightness);
            LayoutParams layoutpars = window.getAttributes();
            layoutpars.screenBrightness = brightness / (float)255;
            window.setAttributes(layoutpars);
        }

        public void onStartTrackingTouch(SeekBar seekBar)
        {
            //Nothing handled here
        }

        public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser)
        {
            if(progress<=20)
            {
              brightness=20;
            }
            else
            {
                brightness = progress;
            }
            float perc = (brightness /(float)255)*100;
            txtPerc.setText((int)perc +" %");
        }
    });   
}

}

快乐编码......

Answer 3

screenBrightness的值介于0.0f和1.0f之间，也许你的值太大了。 我使用WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON标志，也可以调整屏幕亮度