java - 每次wifi断开时通知

Question

每当 WiFi 离线时，我需要我的应用程序发出通知。

每次 WiFi 连接发生变化时，我都会发出通知。但我需要它只在离线时发出通知。

它还在（应用程序的）启动时发出通知。

我的问题是，如何更改代码以仅在 WiFi 离线时发出通知？现在它会在离线、在线和启动时发出通知。

编码：

 public class MainActivity extends Activity { 
 @Override
 protected void onCreate(Bundle savedInstanceState) {        

 super.onCreate(savedInstanceState);  
 this.registerReceiver(this.mConnReceiver,
    new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION));
 setContentView(R.layout.activity_main);
 }

 private BroadcastReceiver mConnReceiver = new BroadcastReceiver() {
 public void onReceive(Context context, Intent intent) {
 boolean noConnectivity = intent.getBooleanExtra(ConnectivityManager.EXTRA_NO_CONNECTIVITY, false);
 String reason = intent.getStringExtra(ConnectivityManager.EXTRA_REASON);
 boolean isFailover = intent.getBooleanExtra(ConnectivityManager.EXTRA_IS_FAILOVER, false);

 NetworkInfo currentNetworkInfo = (NetworkInfo) intent.getParcelableExtra(ConnectivityManager.EXTRA_NETWORK_INFO);
 NetworkInfo otherNetworkInfo = (NetworkInfo) intent.getParcelableExtra(ConnectivityManager.EXTRA_OTHER_NETWORK_INFO);

 if(currentNetworkInfo.isConnected()){
 } 
 else{showNotification();}

 }
 };

Answer 1

使用它来检查连接InetAddress.isReachable，如果你有连接，该方法返回 true 否则返回 false

Answer 2

使用这条onReceive()线BroadCastReceiver

if(!isNetworkConnectionAvailable(ctx)){
        Toast.makeText(ctx, "Network Connection Available ", Toast.LENGTH_LONG).show();
    }

isNetworkConnectionAvailable() 的代码是

    public static boolean isNetworkConnectionAvailable(Context context)
{
    boolean isNetworkConnectionAvailable = false;

    ConnectivityManager connectivityManager = (ConnectivityManager)context.getSystemService("connectivity");
    NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();

    if(activeNetworkInfo != null) 
    {
        isNetworkConnectionAvailable = activeNetworkInfo.getState() == NetworkInfo.State.CONNECTED;
    }
    return isNetworkConnectionAvailable;
}

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