Android利用广播监听设备网络连接(断网)的变化情况

MainActivity如下:

    package cc.testnetworkchange;        import android.os.Bundle;        import android.app.Activity;        /**        * Demo描述:        * 利用广播监听设备网络连接的变化情况        * 亦可借此监测到设备是否已经断开网络        */        public class MainActivity extends Activity {                    @Override            protected void onCreate(Bundle savedInstanceState) {                super.onCreate(savedInstanceState);                setContentView(R.layout.main);            }        }  

    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;                        }                    }                }                                //没有执行return,则说明当前无网络连接                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);            }                }  

    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);            }        }  

<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="利用广播监听设备网络连接的变化情况"             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="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="当前没有可用的网络"             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="http://schemas.android.com/apk/res/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>                         <!-- 注册显示错误的Activity-->            <activity android:name="cc.testnetworkchange.NetWorkErrorActivity"></activity>                        <!-- 注册广播 -->            <receiver android:name="cc.testnetworkchange.NetWorkChangeBroadcastReceiver">                <intent-filter>                     <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />                 </intent-filter>            </receiver>        </application>        </manifest>