java.lang.NullPointerException in onCreate for some SDK versions - android-studio

Question

Recently I have updated the webview code and updated the apk on playstore. On update, some of the devices are not able to open the app; specifically Android 12 devices. Tried to take reference from other stack post to solve it, but nothing seems to address this specific issue.
Would appreciate if you go through the code below and let me know the issue.
Stack trace from playstore console-> Type: java.lang.RuntimeException
Exception java.lang.RuntimeException:
at android.app.ActivityThread.performLaunchActivity (ActivityThread.java:3846)
at android.app.ActivityThread.handleLaunchActivity (ActivityThread.java:4022)
at android.app.servertransaction.LaunchActivityItem.execute (LaunchActivityItem.java:85)
at android.app.servertransaction.TransactionExecutor.executeCallbacks (TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute (TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage (ActivityThread.java:2336)
at android.os.Handler.dispatchMessage (Handler.java:106)
at android.os.Looper.loop (Looper.java:246)
at android.app.ActivityThread.main (ActivityThread.java:8653)
at java.lang.reflect.Method.invoke
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run (RuntimeInit.java:602)
at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:1130)
Caused by java.lang.NullPointerException: Attempt to invoke virtual method 'void android.webkit.WebView.setWebChromeClient(android.webkit.WebChromeClient)' on a null object reference
at com.careturtle.patient1.MainActivity.onCreate (MainActivity.java:126)
at android.app.Activity.performCreate (Activity.java:8207)
at android.app.Activity.performCreate (Activity.java:8191)
at android.app.Instrumentation.callActivityOnCreate (Instrumentation.java:1309)
at android.app.ActivityThread.performLaunchActivity (ActivityThread.java:3819)
MainActivity
package com.example.test;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.pm.PackageManager;
import android.content.res.Configuration;
import android.graphics.Bitmap;
import android.location.LocationManager;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.os.Handler;
import android.preference.PreferenceManager;
import android.provider.Settings;
import android.view.View;
import android.view.WindowManager;
import android.webkit.CookieManager;
import android.webkit.GeolocationPermissions;
import android.webkit.JsResult;
import android.webkit.WebChromeClient;
import android.webkit.WebResourceRequest;
import android.webkit.WebResourceResponse;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;
import androidx.annotation.NonNull;
import androidx.core.app.ActivityCompat;
//import com.monstertechno.adblocker.AdBlockerWebView;
//import com.monstertechno.adblocker.util.AdBlocker;
public class MainActivity extends Activity {
private static final int LOCATION_PERMISSION_CODE = 1;
public static WebView mWebview;
private android.content.Context Context;
private static String getIntentValue = null;
public static SharedPreferences sharedPreferences;
private ProgressDialog mProgressDialog;
#SuppressLint("SetJavaScriptEnabled")
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_SECURE, WindowManager.LayoutParams.FLAG_SECURE);
setContentView(R.layout.activity_main);
Context = this;
getIntentValue = getIntent().getStringExtra("value");
sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
String token1 = sharedPreferences.getString("regtoken", null);
if (!DetectConnection.checkInternetConnection(this)) {
Toast.makeText(getApplicationContext(), "No Internet Connection!", Toast.LENGTH_LONG).show();
finish(); //Calling this method to close this activity when internet is not available.
} else {
mWebview = (WebView) findViewById(R.id.webview1);
//new AdBlockerWebView.init(this).initializeWebView(mWebview);
WebSettings webSettings = mWebview.getSettings();
if(welcome.action_var == "3"){
mWebview.clearCache(true);
Toast.makeText(getApplicationContext(), "App Reset Successful!", Toast.LENGTH_LONG).show();
welcome.action_var = "0";
}
webSettings.setTextSize(WebSettings.TextSize.NORMAL);
mWebview.getSettings().setJavaScriptEnabled(true);
CookieManager.getInstance().setAcceptCookie(true);
mWebview.setWebChromeClient(new WebChromeClient());
//mWebview.setWebChromeClient(new JsPopupWebViewChrome());
mWebview.setWebViewClient(new CustomWebViewClient());
//mWebview.setWebViewClient(new Browser_home());
webSettings.setJavaScriptEnabled(true);
webSettings.setAllowFileAccess(true);
webSettings.setAppCacheEnabled(true);
//improve WebView Performance
mWebview.getSettings().setRenderPriority(WebSettings.RenderPriority.HIGH);
mWebview.getSettings().setAppCacheEnabled(true);
mWebview.getSettings().setCacheMode(WebSettings.LOAD_CACHE_ELSE_NETWORK);
mWebview.setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY);
webSettings.setDomStorageEnabled(true);
webSettings.setLayoutAlgorithm(WebSettings.LayoutAlgorithm.NARROW_COLUMNS);
webSettings.setUseWideViewPort(true);
webSettings.setSavePassword(true);
webSettings.setSaveFormData(true);
webSettings.setEnableSmoothTransition(true);
//webSettings.setDomStorageEnabled(true);
webSettings.setJavaScriptEnabled(true);
// progress dialog
mProgressDialog = new ProgressDialog(Context);
if(welcome.action_var == "2") {
mWebview.loadUrl("https://www.example.com/faq");
}else if(welcome.action_var == "4") {
mWebview.loadUrl("https://www.example.com/change_language");
}else if (welcome.action_var == "666"){
String qrLink = getIntent().getStringExtra("a");
mWebview.loadUrl(qrLink);
}else{
if (sharedPreferences.getBoolean("isKeyGenerated", true)) {
if (getIntentValue != null) {
mWebview.loadUrl("https://www.example.com/active_token");
getIntentValue = null;
} else {
mWebview.loadUrl("https://www.example.com/testa?reg=" + r);
}
}
}
}
mWebview.setWebChromeClient(new WebChromeClient(){
#Override
public boolean onJsConfirm(WebView view, String url, String message, final JsResult result) {
new AlertDialog.Builder(MainActivity.this)
.setTitle("ALERT!")
.setMessage(message)
.setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
result.confirm();
}
})
.setNegativeButton(android.R.string.cancel, new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
result.cancel();
}
})
.setCancelable(false)
.create()
.show();
// Indicate that we're handling this manually
return true;
}
#Override
public void onGeolocationPermissionsShowPrompt(String origin, GeolocationPermissions.Callback callback){
callback.invoke(origin, true, false);
}
});
if ( Build.VERSION.SDK_INT >= 23){
if (ActivityCompat.checkSelfPermission(MainActivity.this, android.Manifest.permission.ACCESS_FINE_LOCATION) !=
PackageManager.PERMISSION_GRANTED ){
ActivityCompat.requestPermissions(MainActivity.this,
new String[] {android.Manifest.permission.ACCESS_FINE_LOCATION}, LOCATION_PERMISSION_CODE);
//return ;
} else {
if (canGetLocation()) {
//DO SOMETHING USEFUL HERE. ALL GPS PROVIDERS ARE CURRENTLY ENABLED
} else {
//SHOW OUR SETTINGS ALERT, AND LET THE USE TURN ON ALL THE GPS PROVIDERS
Intent intent = new Intent(
Settings.ACTION_LOCATION_SOURCE_SETTINGS);
startActivity(intent);
}
}
}
}
public boolean canGetLocation() {
boolean result = true;
LocationManager lm;
boolean gpsEnabled = false;
boolean networkEnabled = false;
lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
// exceptions will be thrown if provider is not permitted.
try {
gpsEnabled = lm.isProviderEnabled(LocationManager.GPS_PROVIDER);
} catch (Exception ex) {
}
try {
networkEnabled = lm
.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
} catch (Exception ex) {
}
return gpsEnabled && networkEnabled;
}
#Override
public void onRequestPermissionsResult(int requestCode, #NonNull String[] permissions, #NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (requestCode == LOCATION_PERMISSION_CODE) {
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
// Toast.makeText(this, "Permission GRANTED", Toast.LENGTH_SHORT).show();
if (canGetLocation()) {
} else {
//SHOW OUR SETTINGS ALERT, AND LET THE USE TURN ON ALL THE GPS PROVIDERS
Intent intent = new Intent(
Settings.ACTION_LOCATION_SOURCE_SETTINGS);
startActivity(intent);
}
} else {
Toast.makeText(this, "Permission DENIED", Toast.LENGTH_SHORT).show();
}
}
}
// Function to load all URLs in same webview
private class CustomWebViewClient extends WebViewClient {
private static final long TIMEOUT = 25000L;
private Handler timeoutHandler = new Handler();
// #SuppressWarnings("deprecation")
// #Override
// public WebResourceResponse shouldInterceptRequest(WebView view, String url) {
// return AdBlockerWebView.blockAds(view,url) ? AdBlocker.createEmptyResource() :
// super.shouldInterceptRequest(view, url);
//
// }
private Runnable timeoutRunnable = new Runnable() {
#Override
public void run() {
//show some error message here
Intent intent = new Intent(MainActivity.this, noconnection.class);
intent.putExtra("a", "mainactivity is source");
startActivity(intent);
}
};
public boolean shouldOverrideUrlLoading(WebView view, String url) {
if (!DetectConnection.checkInternetConnection(Context)) {
Toast.makeText(Context, "No Internet Connection!", Toast.LENGTH_SHORT).show();
} else if (url.contains("example.com")) {
view.loadUrl(url);
} else {
Intent i = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
startActivity(i);
}
//} else if (url.contains("www.") && !url.contains("www.example.com")) {
// Intent i = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
// startActivity(i);
return true;
}
#Override
public void onPageStarted(WebView view, String url, Bitmap favicon) {
// TODO Auto-generated method stub
super.onPageStarted(view, url, favicon);
timeoutHandler.postDelayed(timeoutRunnable, TIMEOUT);
//on page started, show loading page
mProgressDialog.setCancelable(true);
mProgressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
mProgressDialog.show();
}
#Override
public void onPageFinished(WebView view, String url) {
String currentPage = mWebview.getUrl();
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putString("currentpage", currentPage);
editor.apply();
//after loading page, remove loading page
// TODO Auto-generated method stub
super.onPageFinished(view, url);
timeoutHandler.removeCallbacks(timeoutRunnable);
mProgressDialog.dismiss();
}
#Override
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
mWebview.clearCache(true);
timeoutHandler.removeCallbacks(timeoutRunnable);
Intent intent = new Intent(MainActivity.this, noconnection.class);
intent.putExtra("a", "mainactivity is source");
startActivity(intent);
super.onReceivedError(view, errorCode, description, failingUrl);
}
#Override
public void onReceivedHttpError(WebView view, WebResourceRequest request, WebResourceResponse errorResponse) {
if(Build.VERSION.SDK_INT >= 21) {
if (errorResponse.getStatusCode() != 404) {
mWebview.clearCache(true);
timeoutHandler.removeCallbacks(timeoutRunnable);
Intent intent = new Intent(MainActivity.this, noconnection.class);
intent.putExtra("a", "mainactivity is source");
startActivity(intent);
super.onReceivedHttpError(view, request, errorResponse);
}
}
}
}
//-------------
#Override
public void onBackPressed() {
SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
String currenturl = sharedPreferences.getString("currentpage", null);
mWebview.requestFocus();
if (!DetectConnection.checkInternetConnection(Context)) {
Toast.makeText(Context, "No Internet Connection!", Toast.LENGTH_SHORT).show();
}else if (currenturl.contains("https://www.example.com/welcome") || currenturl.contains("https://www.example.com/login") || currenturl.contains("https://www.example.com/faq") || currenturl.contains("https://www.example.com/change_language")){
Intent intent = new Intent(MainActivity.this, welcome.class);
intent.putExtra("a", "mainactivity is source");
startActivity(intent);
}else {
mWebview.goBack();
}
if (mWebview.canGoBack()) {
if (!DetectConnection.checkInternetConnection(Context)) {
Toast.makeText(Context, "No Internet Connection!", Toast.LENGTH_SHORT).show();
}
}
}
public static void loadUrl(String key) {
if (getIntentValue != null) {
mWebview.loadUrl("https://www.example.com/welcome");
getIntentValue = null;
} else {
try {
mWebview.loadUrl("https://www.example.com/testa?reg=" + r);
}catch (Exception e){
}
}
}
public static void reLoad() {
mWebview.reload();
}
#Override
public void onConfigurationChanged(Configuration newConfig){
super.onConfigurationChanged(newConfig);
}
}
Build.Gradle
apply plugin: 'com.android.application'
android {
compileSdkVersion 31
buildToolsVersion '30.0.3'
defaultConfig {
applicationId "com.example.test"
minSdkVersion 24
targetSdkVersion 31
versionCode 48
versionName "5.6"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
compileOptions {
sourceCompatibility = '1.8'
targetCompatibility = '1.8'
}
}
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
androidTestImplementation('com.android.support.test.espresso:espresso-core:2.2.2', {
exclude group: 'com.android.support', module: 'support-annotations'
})
testImplementation 'junit:junit:4.12'
implementation 'com.android.support.constraint:constraint-layout:1.0.0-alpha7'
implementation 'com.google.firebase:firebase-messaging:11.0.4'
//noinspection GradleCompatible
implementation 'com.android.support:appcompat-v7:28.0.0'
//implementation 'com.github.MonsterTechnoGits:WebViewAdblock:1.1'
// implementation 'me.dm7.barcodescanner:zxing:1.9'
def camerax_version = "1.0.0-beta07"
implementation "androidx.camera:camera-camera2:$camerax_version"
implementation "androidx.camera:camera-lifecycle:$camerax_version"
implementation "androidx.camera:camera-view:1.0.0-alpha14"
implementation 'com.google.zxing:core:3.3.3'
implementation 'com.journeyapps:zxing-android-embedded:4.1.0'
}
apply plugin: 'com.google.gms.google-services'
Manifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
package="com.example.test">
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"></uses-permission>
<uses-feature android:name="android.hardware.camera" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.CAMERA2" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<meta-data
android:name="android.webkit.WebView.EnableSafeBrowsing"
android:value="true" />
<application
android:allowBackup="true"
android:icon="#mipmap/ic_icon"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_icon"
android:supportsRtl="true"
android:theme="#style/AppTheme"
tools:replace="android:allowBackup,icon,theme,label"
android:usesCleartextTraffic="true">
<activity
android:name=".ScannerActivity"
android:configChanges="orientation|screenSize"
android:screenOrientation="portrait"></activity>
<activity
android:name=".MainActivity"
android:screenOrientation="portrait"></activity>
<activity
android:name=".SimpleScannerActivity"
android:configChanges="orientation|screenSize"
android:screenOrientation="portrait"></activity>
<activity
android:name="com.example.test.welcome"
android:configChanges="orientation|screenSize"
android:screenOrientation="portrait"
android:exported="true"
android:launchMode="singleTop"
tools:replace="android:screenOrientation"
>
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
<intent-filter>
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<category android:name="android.intent.category.BROWSABLE" />
<data
android:scheme="http"
android:host="www.example.com"
/>
</intent-filter>
</activity>
<!-- http://play.google.com/store/apps/details?id=com.example.test -->
<!-- Accepts URIs that begin with "http://example.com/test/test1" -->
<!-- <data android:scheme="myapp" />
<data android:scheme="http" android:host="careturtle1.com" android:pathPrefix="/barcode"/>
<intent-filter
android:label="#string/app_name">
<action android:name="android.intent.action.VIEW" />
<data
android:host="play.google.com/store/apps/details?id="
android:pathPrefix="/com.example.test"
android:scheme="http"/>
<category android:name="android.intent.category.DEFAULT" />
<category android:name="android.intent.category.BROWSABLE" />
</intent-filter>
-->
<service android:name=".MyFirebaseInstanceId"
android:exported="false">
<intent-filter>
<action android:name="com.google.firebase.INSTANCE_ID_EVENT" />
</intent-filter>
</service>
<service android:name=".FcmMessagingService"
android:exported="false">
<intent-filter>
<action android:name="com.google.firebase.MESSAGING_EVENT" />
</intent-filter>
</service>
<meta-data
android:name="com.google.firebase.messaging.default_notification_icon"
android:resource="#mipmap/ic_icon" />
<activity
android:name=".noconnection"
android:screenOrientation="portrait"></activity>
</application>
</manifest>