Android利用廣播監聽設備網絡連接(斷網)的變化情況

MainActivity如下:

    package cc.testnetworkchange;

    import android.os.Bundle;

    import android.app.Activity;

    /**


 * Demo描述: 
 * 利用廣播監聽設備網絡連接的變化情況 
 * 亦可借此監測到設備是否已經斷開網絡 
 */  
public class MainActivity extends Activity {  

    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.main);  
    }  
}  </pre>NetWorkChangeBroadcastReceiver如下:<pre class="brush:java; toolbar: true; auto-links: false;">    package cc.testnetworkchange;  
import android.content.BroadcastReceiver;  
import android.content.Context;  
import android.content.Intent;  
import android.net.ConnectivityManager;  
import android.net.NetworkInfo;  
import android.net.NetworkInfo.State;  

public class NetWorkChangeBroadcastReceiver extends BroadcastReceiver {  

    @Override  
    public void onReceive(Context context, Intent intent) {  
        ConnectivityManager connectivityManager=  
        (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);  
        if (connectivityManager!=null) {  
            NetworkInfo [] networkInfos=connectivityManager.getAllNetworkInfo();  
            for (int i = 0; i < networkInfos.length; i++) {  
                State state=networkInfos[i].getState();  
                if (NetworkInfo.State.CONNECTED==state) {  
                    System.out.println("------------> Network is ok");  
                    return;  
                }  
            }  
        }  

        //沒有執行return,則說明當前無網絡連接  
        System.out.println("------------> Network is validate");  
        intent.setClass(context, NetWorkErrorActivity.class);  
        intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP|Intent.FLAG_ACTIVITY_NEW_TASK);  
        context.startActivity(intent);  
    }  

}  </pre>NetWorkErrorActivity如下:<pre class="brush:java; toolbar: true; auto-links: false;">    package cc.testnetworkchange;  
import android.os.Bundle;  
import android.app.Activity;  
public class NetWorkErrorActivity extends Activity {  

    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.networkerror);  
    }  
}  </pre>main.xml如下:<pre class="brush:xml; toolbar: true; auto-links: false;"><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"  
xmlns:tools="http://schemas.android.com/tools"  
android:layout_width="match_parent"  
android:layout_height="match_parent"  

>

<TextView  
    android:layout_width="wrap_content"  
    android:layout_height="wrap_content"  
    android:text="利用廣播監聽設備網絡連接的變化情況"   
    android:layout_centerInParent="true"  

/>
</RelativeLayout></pre><br>

networkerror.mxl如下:

<pre></pre>

<pre class="html" name="code"><pre class="html" name="code"><RelativeLayout xmlns:android="
    xmlns:tools="
    android:layout_width="match_parent"

    android:layout_height="match_parent"

 >


<TextView  
    android:layout_width="wrap_content"  
    android:layout_height="wrap_content"  
    android:text="當前沒有可用的網絡"   
    android:layout_centerInParent="true"  

/>
</RelativeLayout></pre><br>

manifest.xml如下:

<pre></pre>

<pre class="html" name="code"><pre class="html" name="code"><?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="
    package="cc.testnetworkchange"

    android:versionCode="1"

    android:versionName="1.0" >


<uses-sdk  
    android:minSdkVersion="8"  
    android:targetSdkVersion="8" />  


<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="cc.testnetworkchange.MainActivity"  
        android:label="@string/app_name" >  
        <intent-filter>  
            <action android:name="android.intent.action.MAIN" />  

            <category android:name="android.intent.category.LAUNCHER" />  
        </intent-filter>  

    </activity>  

     <!-- 注冊顯示錯誤的Activity-->  
    <activity android:name="cc.testnetworkchange.NetWorkErrorActivity"></activity>  

    <!-- 注冊廣播 -->  
    <receiver android:name="cc.testnetworkchange.NetWorkChangeBroadcastReceiver">  
        <intent-filter>  
             <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />  
         </intent-filter>  
    </receiver>  
</application>  


</manifest></pre>