此操作要用真机运行才能方向屏幕亮度的改变，在模拟器上是看不出来的
在main.xml中
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<ImageView
android:id="@+id/pic"
android:src="@drawable/android_book"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>
<SeekBar
android:id="@+id/seekbar"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>
</LinearLayout>
在MySeekBarDemo.java程序中
package com.tarena.seekbar;
import android.app.Activity;
import android.os.Bundle;
import android.text.method.ScrollingMovementMethod;
import android.view.WindowManager;
import android.widget.ImageView;
import android.widget.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;
import android.widget.TextView;
public class MySeekBarDemo extends Activity {
private SeekBar seekbar = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
super.setContentView(R.layout.main);
this.seekbar = (SeekBar) super.findViewById(R.id.seekbar); //取得组件
this.seekbar.setMax(100);
this.seekbar.setOnSeekBarChangeListener(new OnSeekBarChangeListenerImpl());
}
private class OnSeekBarChangeListenerImpl implements OnSeekBarChangeListener{
public void onProgressChanged(SeekBar seekBar, int progress,
boolean fromUser) {
MySeekBarDemo.this.setScreenBrightness((float)seekBar
.getProgress()/100);
}
public void onStartTrackingTouch(SeekBar seekBar) {
}
public void onStopTrackingTouch(SeekBar seekBar) {
}
}
private void setScreenBrightness(float num){
WindowManager.LayoutParams layoutParams = super
.getWindow().getAttributes(); //取得屏幕的属性
layoutParams.screenBrightness = num; //设置屏幕的亮度
super.getWindow().setAttributes(layoutParams); //重新设置窗口的属性
}
}