网络状态判断并且跳到设置页面

package com.example.networkstatus;

import android.net.ConnectivityManager;
import android.os.Bundle;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.AlertDialog.Builder;
import android.content.ComponentName;
import android.content.DialogInterface;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup.LayoutParams;
import android.widget.Button;
import android.widget.LinearLayout;

public class MainActivity extends Activity implements OnClickListener{

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Button button=new Button(this);
button.setText("TextNet");
setContentView(button);
button.setOnClickListener(this);
}

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
boolean flag=false;
ConnectivityManager cwjManager=(ConnectivityManager)getSystemService(this.CONNECTIVITY_SERVICE);
if(cwjManager.getActiveNetworkInfo()!=null)
flag=cwjManager.getActiveNetworkInfo().isAvailable();
if(!flag){
Builder b=new AlertDialog.Builder(this).setTitle("没有可用的网络").setMessage("请开启GPRS或WIFI网路连接");
b.setPositiveButton("确定",new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
Intent mIntent=new Intent("android.settings.WIRELESS_SETTINGS");
startActivity(mIntent);
}
}).setNegativeButton("取消", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub dialog.cancel();
}
}).create(); b.show();
}
}
}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.networkstatus"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="18" />
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.networkstatus.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />

7fe0
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>

</manifest>