Android WebView: Can't go back to previous page

Question

(I'm a newbie) I bought an android app source from a guy and I replaced his links with mine, so now the webview points to my website. Everything works fine, but I have an issue with the back button. If I press it, the app closes (more like minimize, the app keeps running in the background) instead of going back to the previous page. I've tried multiple solutions that I've found on google, but all of them are doing the same thing. The guy I bought it from is not responding to my messages, so I asked here, maybe you guys would help me out.

I will provide any other info needed. I don't want to become an app dev, so I would appreciate if you guys could explain the solution in more simple terms.

MainActivity.java (I hope that this is the code that needs to be modified)

/*
       Licensed to the Apache Software Foundation (ASF) under one
       or more contributor license agreements.  See the NOTICE file
       distributed with this work for additional information
       regarding copyright ownership.  The ASF licenses this file
       to you under the Apache License, Version 2.0 (the
       "License"); you may not use this file except in compliance
       with the License.  You may obtain a copy of the License at

         http://www.apache.org/licenses/LICENSE-2.0

       Unless required by applicable law or agreed to in writing,
       software distributed under the License is distributed on an
       "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
       KIND, either express or implied.  See the License for the
       specific language governing permissions and limitations
       under the License.
 */

package com.myapp.music;

import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.widget.Toast;

import com.google.android.gms.ads.AdRequest;
import com.google.android.gms.ads.InterstitialAd;
import com.onesignal.OneSignal;

import org.apache.cordova.*;

public class MainActivity extends CordovaActivity
{
    boolean doubleBackToExitPressedOnce = false;
    private InterstitialAd mInterstitialAd;

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);

        Bundle extras = getIntent().getExtras();
        if (extras != null && extras.getBoolean("cdvStartInBackground", false)) {
            moveTaskToBack(true);
        }


        ConnectivityManager cm = (ConnectivityManager) this.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
        if (activeNetwork != null && activeNetwork.isConnected()) {
            loadUrl(launchUrl);
        }

        else {

            Toast.makeText(this,"Device is not connected to the internet",Toast.LENGTH_LONG).show();

            AlertDialog.Builder builder = new AlertDialog.Builder(this);
            builder.setTitle("Error :(");
            builder.setMessage("No internet connection").setCancelable(false)

                    .setPositiveButton("OK", new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int id) {
                            finish();
                        }
                    });
            AlertDialog alert = builder.create();
            alert.show();


        }


        //OneSignal Push Notification
        OneSignal.startInit(this)
                .inFocusDisplaying(OneSignal.OSInFocusDisplayOption.Notification)
                .unsubscribeWhenNotificationsAreDisabled(true)
                .init();

        //Interstitial - To enable the Admob Ads, Uncomment the below code

             /* prepareAd();

        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                if (mInterstitialAd.isLoaded()) {
                    mInterstitialAd.show();
                } else {
                    Log.d("TAG", " Interstitial AD not loaded");
                }

            }
        }, 30000); //Ads will be shown after 30 seconds */

        UiChangeListener();

    }

    public void UiChangeListener()
    {
        final View decorView = getWindow().getDecorView();
        decorView.setOnSystemUiVisibilityChangeListener (new View.OnSystemUiVisibilityChangeListener() {
            @Override
            public void onSystemUiVisibilityChange(int visibility) {
                if ((visibility & View.SYSTEM_UI_FLAG_FULLSCREEN) == 0) {
                    decorView.setSystemUiVisibility(
                            View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                                    | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                                    | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
                                    | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
                                    | View.SYSTEM_UI_FLAG_FULLSCREEN
                                    | View.SYSTEM_UI_FLAG_IMMERSIVE);
                }
            }
        });

    }

    public void onBackPressed() {
        if (doubleBackToExitPressedOnce) {
            super.onBackPressed();
            return;
        }

        this.doubleBackToExitPressedOnce = true;
        Toast.makeText(this, "Press again to exit", Toast.LENGTH_SHORT).show();

        new Handler().postDelayed(new Runnable() {

            @Override
            public void run() {
                doubleBackToExitPressedOnce=false;
            }
        }, 2000);
    }

    public void  prepareAd(){

        mInterstitialAd = new InterstitialAd(this);
        mInterstitialAd.setAdUnitId(""); //replace with your Admob ID
        mInterstitialAd.loadAd(new AdRequest.Builder().build());
    }
}

Take a look into this post: https://stackoverflow.com/questions/12338337/phonegap-android-exit-on-backbutton — Artur Schwarz, Feb 06 '18 at 09:31

score 2 · Answer 1 · answered Jan 13 '18 at 13:38

2

in onBackButtonPressed use this

public void onBackPressed() {
        if (doubleBackToExitPressedOnce) {
            super.onBackPressed();
            return;
        }

      if(webView.canGoBack()){
         webView.goBack();
       }

        this.doubleBackToExitPressedOnce = true;
        Toast.makeText(this, "Press again to exit", Toast.LENGTH_SHORT).show();

        new Handler().postDelayed(new Runnable() {

            @Override
            public void run() {
                doubleBackToExitPressedOnce=false;
            }
        }, 2000);
    }

answered Jan 13 '18 at 13:38

Yogesh Choudhary Paliyal

604
1
8
23

Hmm, I get this: "Cannot resolve symbol 'webView' " >> Error:(133, 12) error: cannot find symbol variable webView – Everything Music Jan 13 '18 at 14:27
change webView with your webview. – Yogesh Choudhary Paliyal Jan 13 '18 at 17:49
Do you have any idea where it could be declared? – Everything Music Jan 13 '18 at 18:42
yes in on create webview=(WebView)findViewById(R.id.webView); – Yogesh Choudhary Paliyal Jan 15 '18 at 05:10
Error: cannot find symbol method goBack() – Everything Music Jan 15 '18 at 13:51
Can you help me out please? – Everything Music Jan 17 '18 at 23:19
Ok, thanks. So, can you tell me what's wrong with my code? As I said, I get the following error: 'cannot find symbol method goBack() - My code: https://pastebin.com/6wbjigwQ – Everything Music Jan 18 '18 at 21:36

Android WebView: Can't go back to previous page

1 Answers1