Android 调节屏幕亮度问题
研究调节屏幕亮度时遇到的问解决方案如下：
1、可以通过获取当前Activity 的WindowManager.LayoutParams 属性，然后设置其screenBrightness的值即可；
screenBrightness 的取值范围在[0,1]之间，具体可以如下操作：
WindowManager.LayoutParams lp = getWindow().getAttributes();
lp.screenBrightness = 0.5;
getWindow().setAttributes(lp);
2、有时我们需要用一个Seekbar控件来动态控制屏幕的亮度。
首先获取系统屏幕的最大值，然后设置seekbar的setMax。
/**
* 获取屏幕亮度
*/
private int getScreenBrightness() {
int nowBrightnessValue = 0;
ContentResolver resolver = getContentResolver();
try {
nowBrightnessValue = android.provider.Settings.System.getInt(resolver,
Settings.System.SCREEN_BRIGHTNESS);
} catch (Exception e) {
e.printStackTrace();
}
return nowBrightnessValue;
}
然后在调节屏幕亮度函数中与seekbar进行绑定
private void setScreenLight(View popupView) {
mBrightnessProgress = getScreenBrightness();
final SeekBar mSeekBarLight = (SeekBar) popupView.findViewById(R.id.seekBarLight);
mSeekBarLight.setProgress(mBrightnessProgress);
mSeekBarLight.setMax(MAX_BRIGHTNESS);
mSeekBarLight.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
@Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
// TODO Auto-generated method stub
if (fromUser) {
WindowManager.LayoutParams lp = getWindow().getAttributes();
lp.screenBrightness = (float) (progress / (MAX_BRIGHTNESS * 1.0));
getWindow().setAttributes(lp);
}
}
@Override
public void onStartTrackingTouch(SeekBar arg0) {
// TODO Auto-generated method stub
}
@Override
public void onStopTrackingTouch(SeekBar arg0) {
// TODO Auto-generated method stub
}
});
}
3、当我们遇到把Activity做为子Activity潜入到TabActivity 或者 ViewGroup 类容器时，通常上面的方法设置无法取得成功，
活动滚动条的过程中，屏幕亮度不发生改变。
因为调节亮度作用域发生了改变，之前是在Activity里面对亮度修改， 而现在是作为子activity对TabActivity或ViewGroup 容器进行修改，因此不能成功，需要
通过getParent（）方法获取器Parent，然后设置。
private void setScreenLight(View popupView) {
mBrightnessProgress = getScreenBrightness();
final SeekBar mSeekBarLight = (SeekBar) popupView.findViewById(R.id.seekBarLight);
mSeekBarLight.setProgress(mBrightnessProgress);
mSeekBarLight.setMax(MAX_BRIGHTNESS);
mSeekBarLight.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
@Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
// TODO Auto-generated method stub
if (fromUser) {
WindowManager.LayoutParams lp = getParent().getWindow().getAttributes();
lp.screenBrightness = (float) (progress / (MAX_BRIGHTNESS * 1.0));
getParent().getWindow().setAttributes(lp);
}
}
@Override
public void onStartTrackingTouch(SeekBar arg0) {
// TODO Auto-generated method stub
}
@Override
public void onStopTrackingTouch(SeekBar arg0) {
// TODO Auto-generated method stub
}
});
}