如何解决设备断开网络连接后如何接收通知?
| 我知道您可以编写代码来确定设备是否已连接到网络。 但是在我的应用程序中,如果设备将其状态从“网络”更改为“无网络”,我想做的就是得到通知。例如,当用户进入隧道并丢失信号时,就会发生这种情况。或者,当使用WiFi时,用户超出了接入点的范围,无法再访问Internet。 Android API是否提供了一些您可以在其中注册侦听器的工具,以便每次网络状态发生变化时都得到通知? 我找到了这段代码并尝试使用它,但是它没有任何作用。网络状态更改时,我没有收到任何通知。public class ConnectivityManager extends PhonestateListener{
Activity activity;
public ConnectivityManager(Activity a){
TelephonyManager telephonyManager = (TelephonyManager)a.getSystemService(Context.TELEPHONY_SERVICE);
telephonyManager.listen(this,PhonestateListener.LISTEN_DATA_CONNECTION_STATE);
activity = a;
}
@Override
public void onDataConnectionStateChanged(int state) {
super.onDataConnectionStateChanged(state);
switch (state) {
case TelephonyManager.DATA_disCONNECTED:
new AlertDialog.Builder(activity).
setCancelable(false).
setTitle(\"Connection Manager\").
setMessage(\"There is no network connection. Please connect to internet and start again.\").
setNeutralButton(\"Ok\",new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int whichButton) {
System.exit(0);
}
}).create();
break;
case TelephonyManager.DATA_CONNECTED:
break;
}
}
}
另外,我在AndroidManifest.xml中添加了适当的权限:
<uses-permission android:name=\"android.permission.INTERNET\"></uses-permission>
<uses-permission android:name=\"android.permission.READ_PHONE_STATE\"></uses-permission>
<uses-permission android:name=\"android.permission.ACCESS_NETWORK_STATE\"></uses-permission>
解决方法
myTelephonyManager=(TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);
callStateListener = new PhoneStateListener(){
public void onDataConnectionStateChanged(int state){
switch(state){
case TelephonyManager.DATA_DISCONNECTED:
Log.i(\"State: \",\"Offline\");
// String stateString = \"Offline\";
// Toast.makeText(getApplicationContext(),// stateString,Toast.LENGTH_LONG).show();
break;
case TelephonyManager.DATA_SUSPENDED:
Log.i(\"State: \",\"IDLE\");
// stateString = \"Idle\";
// Toast.makeText(getApplicationContext(),Toast.LENGTH_LONG).show();
break;
}
}
};
myTelephonyManager.listen(callStateListener,PhoneStateListener.LISTEN_DATA_CONNECTION_STATE);
, 您可能要考虑使用BroadcastReceiver
代替ConnectivityManager.CONNECTIVITY_ACTION
。从文档:
网络连接发生了变化。连接已建立或丢失。受影响的网络的NetworkInfo作为附加发送。应该咨询一下发生了哪种连接事件。
与“ 5”不同,此接收器可用于WiFi和蜂窝数据连接,后者仅会通知您蜂窝网络的变化。
, 接受的答案对我不起作用(我的平板电脑已连接到WiFi-没有3G)。以下代码为我工作:
public class ConnectivityChangeReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context,Intent intent) {
System.out.println(\"*** Action: \" + intent.getAction());
if(intent.getAction().equalsIgnoreCase(\"android.net.conn.CONNECTIVITY_CHANGE\")) {
Toast.makeText(context,\"Connection changed\",Toast.LENGTH_SHORT).show();
}
}
}
并更改为AndroidManifest.xml
<uses-permission android:name=\"android.permission.ACCESS_NETWORK_STATE\" />
<receiver android:name=\".custom.ConnectivityChangeReceiver\">
<intent-filter>
<action android:name=\"android.net.conn.CONNECTIVITY_CHANGE\" />
</intent-filter>
</receiver>
, 不确定是否会有所帮助,但这看起来很相似...
, 我通过轮询ConnectivityManager来实现此功能。
_connectivityManager = (ConnectivityManager)getSystemService(CONNECTIVITY_SERVICE);
一旦我们有了连接管理器,就不时轮询它,然后查看您是否仍然连接
private final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
final Runnable networkStatusChecker = new Runnable() {
public void run() {
NetworkInfo activeNetwork = _connectivityManager.getActiveNetworkInfo();
boolean isConnected = activeNetwork != null && activeNetwork.isConnectedOrConnecting();
if(!isConnected) {
System.out.println(\"disconnected from network\");
networkCheckerHandle.cancel(true);
}
}
};
final ScheduledFuture networkCheckerHandle = scheduler.scheduleAtFixedRate(networkStatusChecker,10,SECONDS);
, 如果您想在Kotlin中这样做。用这个
val isInternetWorking: Boolean by lazy {
var success = false
try {
val url = URL(\"https://google.com\")
val connection = url.openConnection() as HttpURLConnection
connection.connectTimeout = 10000
connection.connect()
success = connection.responseCode === 200
} catch (e: IOException) {
e.printStackTrace()
}
return@lazy success
}
在线程中执行此操作。
, 您可以轻松使用Merlin和他的胡须。在这里,您还可以获得连接类型:移动或wifi。
implementation \'com.novoda:merlin:1.2.0\'
private MerlinsBeard merlinsBeard;
private NetworkChecker(Context context){
Merlin merlin = new Merlin.Builder()
.withConnectableCallbacks()
.withDisconnectableCallbacks()
.build(context);
merlinsBeard = new MerlinsBeard.Builder().build(context);
merlin.registerConnectable(() -> {
Timber.d(\"Connection enabled\");
});
merlin.registerDisconnectable(() -> {
Timber.d(\"Connection disabled\");
});
merlin.bind();
}
public boolean getConnected(){
return merlinsBeard.isConnected();
}
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