Automatically refresh Activity when Internet is there

Question

I have an ActivityNonetwork.java Activity. The purpose of that file is that when there is no network/internet, the ActivityNonetwork activity is shown.

I tried it, I turned off the internet and this page was shown (Successful!!!), but when I again turn on the internet, the page does not refresh and the same page is being shown even after I turn the internet on.

My ActivityNonetwork.java code:

package com.Notely.SplashScreenandAccounts;

import androidx.activity.OnBackPressedCallback;
import androidx.activity.OnBackPressedDispatcherOwner;
import androidx.appcompat.app.AppCompatActivity;

import android.content.Context;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

import com.Notely.Notes.ActivityDashboard;

public class ActivityNonetwork extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_nonetwork);

    final Button exit = findViewById(R.id.exit);
    final Button retry = findViewById(R.id.retry);

    exit.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            exitApp();
        }
    });
    retry.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            retryApp();
        }
    });

    if (checkNetwork() == true) {
        finish();
        overridePendingTransition(0, 0);
        startActivity(getIntent());
        overridePendingTransition(0, 0);

        Intent activitySplash = new Intent(this, ActivitySplash.class);
        startActivity(activitySplash);
    }
}

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

public void exitApp() {
    Intent exitApp = new Intent(Intent.ACTION_MAIN);
    exitApp.addCategory( Intent.CATEGORY_HOME );
    exitApp.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
    startActivity(exitApp);
}

public void retryApp() {
    Intent retryApp = new Intent(this, ActivitySplash.class);
    startActivity(retryApp);
}

@Override
public void onBackPressed() {
    super.onBackPressed();
    Intent exitApp = new Intent(Intent.ACTION_MAIN);
    exitApp.addCategory( Intent.CATEGORY_HOME );
    exitApp.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
    startActivity(exitApp);
}
}

Is there any way in which we can refresh the page when the internet comes?

Answer 1

you just check network connection when activity created, you have to initialize observer for network changes

read this article and manage your network connection

Answer 2

You can achieve this using broadcast receiver in your project

Create a class as below -

public class NetworkChangeReceiver extends BroadcastReceiver {

@Override
public void onReceive(final Context context, final Intent intent) {
   PrefManager.getInstance(context).setPreviousNetworkStatus
   (NetworkUtil.getConnectivityStatusString(context));
 }
}

Then create below class -

class NetworkUtil {

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


private 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;
}

static String getConnectivityStatusString(Context context) {
    int conn = NetworkUtil.getConnectivityStatus(context);
    String status = null;
    if (conn == NetworkUtil.TYPE_WIFI) {
        status = context.getString(R.string.wifi_enabled);
    } else if (conn == NetworkUtil.TYPE_MOBILE) {
        status = context.getString(R.string.mobile_data_enable);
    } else if (conn == NetworkUtil.TYPE_NOT_CONNECTED) {
        status = context.getString(R.string.not_connected_to_internet);
    }
    return status;
 }
}

Create a PrefsManager class - This is not mandatory to create a separate class for this funcionality. You can add this code to your MainActivity.

public class PrefManager {

public static final String PREVIOUS_NETWORK_STATE = "previous_network_state";

private static SharedPreferences sharedPreferences;
private static PrefManager prefManager;

private PrefManager(Context context) {
    sharedPreferences = context.getSharedPreferences(PREFERENCE_NAME, 
    Context.MODE_PRIVATE);
}

public static PrefManager getInstance(Context context) {
    if (prefManager == null) {
        prefManager = new PrefManager(context);
    }
    return prefManager;
}

public SharedPreferences getSharedPreferences() {
    return sharedPreferences;
}

public void setPreviousNetworkStatus(String status) {
    sharedPreferences.edit().putString(PREVIOUS_NETWORK_STATE, status).apply();
}

public String getPreviousNetworkStatus() {
    return sharedPreferences.getString(PREVIOUS_NETWORK_STATE, "");
}
}

In MainActivity

 private NetworkChangeReceiver networkChangeReceiver = NetworkChangeReceiver()

In onCreate method register receiver

 registerReceiver(
        networkChangeReceiver,
        IntentFilter("android.net.conn.CONNECTIVITY_CHANGE")
    )

Override below method

@Override void onSharedPreferenceChanged(SharedPreferences sharedPreferences,String 
key) {
    if (key == PrefManager.PREVIOUS_NETWORK_STATE) {
        onNetworkChanged()
    }
 }

Then create this method -

private void onNetworkChanged() {
    // your code here 

    finish();
    overridePendingTransition(0, 0);
    startActivity(getIntent());
    overridePendingTransition(0, 0);

    Intent activitySplash = new Intent(this, ActivitySplash.class);
    startActivity(activitySplash);
}

unregister receiver in onDestroy method

 unregisterReceiver(networkChangeReceiver)

I hope this will work for you.