首先，我们来看一下这个程序的运行截图：
首先点击菜单键，我们会看到菜单中有两个选项，一个是选择背光颜色，另一个是离开按钮，当我们点击背光颜色之后，会出现如上所示的效果。
接着，我们点击蓝色背光，出现如下所示的画面：
实现这个程序很简单，下面给出实现的代码：
1.主程序文件
package irdc.ex10_01;
/* import相关class */
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.os.Bundle;
import android.os.PowerManager;
import android.view.Menu;
import android.view.MenuItem;
import android.view.Window;
import android.view.WindowManager;
import android.widget.LinearLayout;
import android.widget.Toast;
public class EX10_01 extends Activity
{
/*
* PowerManager可以控制手机的wakelock，使手机处于恒亮的状态
*/
private boolean ifLocked = false;
private PowerManager.WakeLock mWakeLock;
private PowerManager mPowerManager;
private LinearLayout mLinearLayout;
/* 独一无二的menu选项identifier，用以识别事件 */
static final private int M_CHOOSE = Menu.FIRST;
static final private int M_EXIT = Menu.FIRST+1;
/* 颜色菜单的颜色与文字数组 */
private int[] color={R.drawable.white,R.drawable.blue,
R.drawable.pink,R.drawable.green,
R.drawable.orange,R.drawable.yellow};
private int[] text={R.string.str_white,R.string.str_blue,
R.string.str_pink,R.string.str_green,
R.string.str_orange,R.string.str_yellow};
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
/* 必须?setContentView之前调用全屏显示 */
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags
(
WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN
);
setContentView(R.layout.main);
/* 初始化mLinearLayout */
mLinearLayout=(LinearLayout)findViewById(R.id.myLinearLayout1);
/* 取得PowerManager */
mPowerManager = (PowerManager)
getSystemService(Context.POWER_SERVICE);
/* 取得WakeLock */
mWakeLock = mPowerManager.newWakeLock
(
PowerManager.SCREEN_BRIGHT_WAKE_LOCK, "BackLight"
);
WindowManager.LayoutParams lp = getWindow().getAttributes();
lp.screenBrightness = 1.0f;
getWindow().setAttributes(lp);
}
@Override
public boolean onCreateOptionsMenu(Menu menu)
{
/* menu组ID */
int idGroup1 = 0;
/* menuItemID */
int orderMenuItem1 = Menu.NONE;
int orderMenuItem2 = Menu.NONE+1;
/* 建立menu */
menu.add(idGroup1,M_CHOOSE,orderMenuItem1,R.string.str_title);
menu.add(idGroup1,M_EXIT,orderMenuItem2,R.string.str_exit);
menu.setGroupCheckable(idGroup1, true, true);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item)
{
switch(item.getItemId())
{
case (M_CHOOSE):
/* 弹出选择背后颜色的AlertDialog */
new AlertDialog.Builder(EX10_01.this)
.setTitle(getResources().getString(R.string.str_title))
.setAdapter(new MyAdapter(this,color,text),listener1)
.setPositiveButton("取消",
new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog, int which)
{
}
})
.show();
break;
case (M_EXIT):
/* 离开程序 */
this.finish();
break;
}
return super.onOptionsItemSelected(item);
}
/* 选择背后颜色的AlertDialog的OnClickListener */
OnClickListener listener1=new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog,int which)
{
/* 更改背景颜色 */
mLinearLayout.setBackgroundResource(color[which]);
/* Toast显示设定的颜色 */
Toast.makeText(EX10_01.this,
getResources().getString(text[which]),
Toast.LENGTH_LONG).show();
}
};
@Override
protected void onResume()
{
/* onResume()时调用wakeLock() */
wakeLock();
super.onResume();
}
@Override
protected void onPause()
{
/* onPause()时调用wakeUnlock() */
wakeUnlock();
super.onPause();
}
/* 唤起WakeLock的method */
private void wakeLock()
{
if (!ifLocked)
{
ifLocked = true;
mWakeLock.acquire();
}
}
/* 释放WakeLock的method */
private void wakeUnlock()
{
if (ifLocked)
{
mWakeLock.release();
ifLocked = false;
}
}
}
2.Adapter文件
package irdc.ex10_01;
/* import相关class */
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;
/* 自定义的Adapter，继承android.widget.BaseAdapter */
public class MyAdapter extends BaseAdapter
{
private LayoutInflater mInflater;
private int[] color;
private int[] text;
public MyAdapter(Context context,int[] _color,int[] _text)
{
mInflater = LayoutInflater.from(context);
color = _color;
text = _text;
}
/* 因继承BaseAdapter，需重写以下method */
@Override
public int getCount()
{
return text.length;
}
@Override
public Object getItem(int position)
{
return text[position];
}
@Override
public long getItemId(int position)
{
return position;
}
@Override
public View getView(int position,View convertView,ViewGroup par)
{
ViewHolder holder;
if(convertView == null)
{
/* 使用自定义的change_color作为Layout */
convertView = mInflater.inflate(R.layout.change_color, null);
/* 初始化holder的text */
holder = new ViewHolder();
holder.mText=(TextView)convertView.findViewById(R.id.myText);
convertView.setTag(holder);
}
else
{
holder = (ViewHolder) convertView.getTag();
}
holder.mText.setText(text[position]);
holder.mText.setBackgroundResource(color[position]);
return convertView;
}
/* class ViewHolder */
private class ViewHolder
{
TextView mText;
}
}
3.两个布局文件
3.1 主布局
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/myLinearLayout1" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" android:background="@drawable/white" />
3.2 对话框布局
<?xml version="1.0" encoding="utf-8"?> <TextView android:id="@+id/myText" xmlns:android="http://schemas.android.com/apk/res/android" android:layout_gravity="center_vertical" android:layout_width="wrap_content" android:layout_height="wrap_content" android:padding="10px" android:textSize="18px" android:textColor="@drawable/black" />
4.我们需要在程序中加入如下的权限
<uses-permission android:name="android.permission.WAKE_LOCK"/> <uses-permission android:name="android.permission.WRITE_SETTINGS"/> <uses-permission android:name="android.permission.HARDWARE_TEST"/>