android - android如何在互联网连接丢失时得到指示？

Question

我正在开发一个 android 应用程序，我想在互联网（wifi 或数据包数据连接）连接丢失时收到通知。在我的方法中，我可以获得连接的状态：

private boolean isNetworkAvailable() {
ConnectivityManager connectivityManager 
      = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
return activeNetworkInfo != null && activeNetworkInfo.isConnected();
}

在清单中有此内容时：

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

连接丢失时如何自动通知我？

Answer 1

对于 WIFI，您可以将广播接收器注册为：

IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction(WifiManager.SUPPLICANT_CONNECTION_CHANGE_ACTION);
registerReceiver(broadcastReceiver, intentFilter);

您还可以在 Manifest 中注册接收器。

然后在你的接收器中：

@Override
public void onReceive(Context context, Intent intent) {
    final String action = intent.getAction();
    if (action.equals(WifiManager.SUPPLICANT_CONNECTION_CHANGE_ACTION)) {
        if (intent.getBooleanExtra(WifiManager.EXTRA_SUPPLICANT_CONNECTED, false)){
            //do stuff
        } else {
            // wifi connection was lost
        }
    }
}

对于任何类型的数据连接侦听器，您都可以使用以下注册为：

<receiver android:name=".receiver.ConnectivityReceiver">
    <intent-filter>
        <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
        <action android:name="android.net.wifi.WIFI_STATE_CHANGED" />
    </intent-filter>
</receiver>

和你的ConnectivityReceiver：

public class ConnectivityReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
    }
}

在该方法中，您可以使用此开发人员文章onReceive检查您是否有 Internet 连接。

Answer 2

使用以下代码：

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import classes.NetworkUtil;

public class NetworkChangeReceiver extends BroadcastReceiver {

        @Override
        public void onReceive(final Context context, final Intent intent) {

            boolean IsConnected = NetworkUtil.getConnectivityStatusString(context);
           // Toast in here, you can retrieve other value like String from NetworkUtil
           // but you need some change in NetworkUtil Class
        }
    }

并且NetworkUtil是：

package classes;

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;

public class NetworkUtil {

    public static int TYPE_WIFI = 1;
    public static int TYPE_MOBILE = 2;
    public static int TYPE_NOT_CONNECTED = 0;


    public static int getConnectivityStatus(Context context) {
        ConnectivityManager cm = (ConnectivityManager) context
                .getSystemService(Context.CONNECTIVITY_SERVICE);

        NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
        if (null != activeNetwork) {
            if(activeNetwork.getType() == ConnectivityManager.TYPE_WIFI)
                return TYPE_WIFI;

            if(activeNetwork.getType() == ConnectivityManager.TYPE_MOBILE)
                return TYPE_MOBILE;
        } 
        return TYPE_NOT_CONNECTED;
    }

    public static boolean getConnectivityStatusString(Context context) {
        int conn = NetworkUtil.getConnectivityStatus(context);
        boolean status = false ;
        if (conn == NetworkUtil.TYPE_WIFI) {
            status = true;
        } else if (conn == NetworkUtil.TYPE_MOBILE) {
            status = true; 
        } else if (conn == NetworkUtil.TYPE_NOT_CONNECTED) {
            status = false;
        }
        return status;
    }
}

在清单文件中：

 <receiver
            android:name="receiver.NetworkChangeReceiver" >
            <intent-filter>
                <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
            </intent-filter>
        </receiver>

和这个权限：

 <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

Answer 3

您需要设置广播接收器。

将这些添加为意图过滤器。

            <intent-filter>
                <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
                <action android:name="android.net.wifi.WIFI_STATE_CHANGED" />
            </intent-filter>

Answer 4

您应该使用BroadcastReceivers来满足您的要求。创建一个监听网络变化的 BroadcastReceiver。

如果网络发生任何变化，它将自动触发事件，您可以执行有关它的操作。