Android 利用BroadcastReceiver实时检测网络状态变化

一、定义ReceiveService类

当接收到的网络状态发生改变时通知Activity，需要一个Service，并且绑定该到Activity。import 
java.util.Date;import java.util.Timer;import java.util.TimerTask;import android.app.Service;import android.content.BroadcastReceiver;import android.content.Context;import android.content.Intent;import android.content.IntentFilter;import android.net.ConnectivityManager;import android.net.NetworkInfo;import android.os.Binder;import android.os.IBinder;import android.util.Log;public class ReceiveMsgService extends Service {    private BroadcastReceiver mReceiver = new BroadcastReceiver() {        @Override        public void onReceive(Context context, Intent intent) {            String action = intent.getAction();            if (action.equals(ConnectivityManager.CONNECTIVITY_ACTION)) {                Timer timer = new Timer();                timer.schedule(new NetworkTask(getApplicationContext()), new Date());            }        }    };    public interface GetConnectState {        void GetState(boolean isConnected); // 网络状态改变之后，通过此接口的实例通知当前网络的状态，此接口在Activity中注入实例对象    }    private GetConnectState onGetConnectState;    public void setOnGetConnectState(GetConnectState onGetConnectState) {        this.onGetConnectState = onGetConnectState;    }    private Binder binder = new MyBinder();    private boolean isConnected = true;    @Override    public IBinder onBind(Intent intent) {        return binder;    }    @Override    public void onCreate() {// 注册广播        IntentFilter mFilter = new IntentFilter();        mFilter.addAction(ConnectivityManager.CONNECTIVITY_ACTION); // 添加接收网络连接状态改变的Action        registerReceiver(mReceiver, mFilter);    }    class NetworkTask extends TimerTask {        private Context context;        public NetworkTask(Context context) {            this.context = context;        }        @Override        public void run() {            if (isNetworkConnected(context)) {                isConnected = true;            } else {                isConnected = false;            }            if (onGetConnectState != null) {                onGetConnectState.GetState(isConnected); // 通知网络状态改变            }        }        /*         * 判断是否有网络连接         */        private boolean isNetworkConnected(Context context) {            ConnectivityManager connectivity = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);            if (connectivity == null) {                return false;            } else {                NetworkInfo[] info = connectivity.getAllNetworkInfo();                if (info != null) {                    for (NetworkInfo net : info) {                        if (net.getState() == NetworkInfo.State.CONNECTED) {                            return true;                        }                    }                }            }            return false;        }    }    public class MyBinder extends Binder {        public ReceiveMsgService getService() {            return ReceiveMsgService.this;        }    }    @Override    public void onDestroy() {        super.onDestroy();        unregisterReceiver(mReceiver); // 删除广播    }} 

二、接下来在Activity中，绑定服务

注意：在TabActivity的子Activity中使用service时，bindService(intent, serviceConnection, Context.BIND_AUTO_CREATE)，需要改为：

            this.getApplicationContext().bindService(intent, serviceConnection, Context.BIND_AUTO_CREATE) ,才可正常使用。

public class MainActivity extends Activity  {  
  
    ReceiveMsgService receiveMsgService;  
    private boolean conncetState = true; // 记录当前连接状态  
  
    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        // TODO Auto-generated method stub  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.page_main);      
        bind();  
    }  
  
    private void bind() {  
        Intent intent = new Intent(MainActivity.this, ReceiveMsgService.class);  
        bindService(intent, serviceConnection, Context.BIND_AUTO_CREATE);  
    }  
  
    private ServiceConnection serviceConnection = new ServiceConnection() {  
        @Override  
        public void onServiceDisconnected(ComponentName name) {  
        }  
  
        @Override  
        public void onServiceConnected(ComponentName name, IBinder service) {  
            receiveMsgService = ((ReceiveMsgService.MyBinder) service)  
                    .getService();  
            receiveMsgService.setOnGetConnectState(new GetConnectState() { // 添加接口实例获取连接状态  
                        @Override  
                        public void GetState(boolean isConnected) {  
                            if (conncetState != isConnected) { // 如果当前连接状态与广播服务返回的状态不同才进行通知显示  
                                conncetState = isConnected;  
                                if (conncetState) {// 已连接  
                                    handler.sendEmptyMessage(1);  
                                } else {// 未连接  
                                    handler.sendEmptyMessage(2);  
                                }  
                            }  
                        }  
                    });  
        }  
    };  
      
    private void unbind() {  
        if (receiveMsgService != null ) {  
            unbindService(serviceConnection);  
        }  
    }  
  
    Handler handler = new Handler() {  
        public void handleMessage(Message msg) {  
  
            switch (msg.what) {  
            case 1:// 已连接  
                Toast.makeText(MainActivity.this, "网络已经连接" ,Toast.LENGTH_LONG).show();  
                break;  
            case 2:// 未连接  
                Toast.makeText(MainActivity.this, "网络未连接" ,Toast.LENGTH_LONG).show();  
                break;  
            default:  
                break;  
            }  
            ;  
        };  
  
    };  
      
    @Override  
    protected void onDestroy()  
    {  
        // TODO Auto-generated method stub  
        super.onDestroy();  
        unbind();  
    }    
}  

三、在Manifest中注册Serevice和相关权限

<usespermission android:name="android.permission.ACCESS_NETWORK_STATE" />   

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" /> //注册service<service android:enabled="true" android:name=".ReceiveMsgService" />