Проверить подключение к интернету

#android

Как при запуске Activity проверять подключение к интернету и если подключение отсутствует,
то выводить сообщение? 
    

Ответы

Ответ 1

import android.annotation.TargetApi
import android.arch.lifecycle.LiveData
import android.content.BroadcastReceiver
import android.content.Context
import android.content.Context.CONNECTIVITY_SERVICE
import android.content.Intent
import android.content.IntentFilter
import android.net.ConnectivityManager
import android.net.Network
import android.net.NetworkInfo
import android.net.NetworkRequest
import android.os.Build
import android.support.annotation.RequiresApi

class ConnectionLiveData(val context: Context) : LiveData() {

    private var connectivityManager: ConnectivityManager = context.getSystemService(CONNECTIVITY_SERVICE)
as ConnectivityManager

    private lateinit var connectivityManagerCallback: ConnectivityManager.NetworkCallback

    override fun onActive() {
        super.onActive()

        updateConnection()

        when {
            Build.VERSION.SDK_INT >= Build.VERSION_CODES.N -> {
                connectivityManager.registerDefaultNetworkCallback(getConnectivityManagerCallback())
            }
            Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP -> {
                lollipopNetworkAvailableRequest()
            }
            else -> {
                if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
                    context.registerReceiver(
                        networkReceiver, 
                        IntentFilter("android.net.conn.CONNECTIVITY_CHANGE")
                    )
                }
            }
        }
    }

    override fun onInactive() {
        super.onInactive()
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            connectivityManager.unregisterNetworkCallback(connectivityManagerCallback)
        } else {
            context.unregisterReceiver(networkReceiver)
        }
    }

    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    private fun lollipopNetworkAvailableRequest() {
        val builder = NetworkRequest.Builder()
            .addTransportType(android.net.NetworkCapabilities.TRANSPORT_CELLULAR)
            .addTransportType(android.net.NetworkCapabilities.TRANSPORT_WIFI)

        connectivityManager.registerNetworkCallback(builder.build(), getConnectivityManagerCallback())
    }

    private fun getConnectivityManagerCallback(): ConnectivityManager.NetworkCallback {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            connectivityManagerCallback = object : ConnectivityManager.NetworkCallback() {
                override fun onAvailable(network: Network?) {
                    postValue(true)
                }

                override fun onLost(network: Network?) {
                    postValue(false)
                }
            }
            return connectivityManagerCallback
        } else {
            throw IllegalAccessError("Should not happened")
        }
    }

    private val networkReceiver = object : BroadcastReceiver() {
        override fun onReceive(context: Context, intent: Intent) {
            updateConnection()
        }
    }

    private fun updateConnection() {
        val activeNetwork: NetworkInfo? = connectivityManager.activeNetworkInfo
        postValue(activeNetwork?.isConnected == true)
    }
}


Вызов:

public override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)

    val connectionLiveData = ConnectionLiveData(this)
    connectionLiveData.observe(this, Observer { isConnected ->
        isConnected?.let {
            //что-то
        }
    })
}





  Deprecated

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

public class ConnectivityReceiver extends BroadcastReceiver {

    public static ConnectivityReceiverListener connectivityReceiverListener;

    public ConnectivityReceiver() {
        super();
    }

    @Override
    public void onReceive(Context context, Intent arg1) {
        NetworkInfo activeNetwork = ((ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE)).getActiveNetworkInfo();
        boolean isConnected = activeNetwork != null && activeNetwork.isConnectedOrConnecting();
        if (connectivityReceiverListener != null) connectivityReceiverListener.onNetworkConnectionChanged(isConnected);
    }

    public static boolean isConnected() {
        NetworkInfo activeNetwork = ((ConnectivityManager) MyApplication.getInstance().getApplicationContext().getSystemService(Context.CONNECTIVITY_SERVICE)).getActiveNetworkInfo();
        return activeNetwork != null && activeNetwork.isConnectedOrConnecting();
    }


    public interface ConnectivityReceiverListener {
        void onNetworkConnectionChanged(boolean isConnected);
    }
}

  
  2.

import android.app.Application;

public class MyApplication extends Application {

    private static MyApplication mInstance;

    @Override
    public void onCreate() {
        super.onCreate();
        mInstance = this;
    }

    public static synchronized MyApplication getInstance() {
        return mInstance;
    }

    public void setConnectivityListener(ConnectivityReceiver.ConnectivityReceiverListener

  
  listener) {
              ConnectivityReceiver.connectivityReceiverListener = listener;
          }
      }
  
  3.




    
    

    
        ...

        
            
                
            
        

    



  
  4.

private void checkConnection() {
    boolean isConnected = ConnectivityReceiver.isConnected();
    showSnack(isConnected);
}


private void showSnack(boolean isConnected) {
    String message;
    if (isConnected) message = "Good! Connected to Internet";
    else message = "Sorry! Not connected to internet";
    Snackbar snackbar = Snackbar.make(findViewById(R.id.fab), message, Snackbar.LENGTH_LONG).show();
}

@Override
protected void onResume() {
    super.onResume();
    MyApplication.getInstance().setConnectivityListener(this);
}

@Override
public void onNetworkConnectionChanged(boolean isConnected) {
    showSnack(isConnected);
}