In my application, I am trying to show a spinner/progressBar while an URL is being loaded on webView but I'm getting "java.lang.NullPointerException: How to solve this problem please refer the below code.
Attempt to invoke virtual method 'void android.widget.ProgressBar.setVisibility(int)' on a null object reference" here id the complete error log.
11-04 17:47:49.952 14105-14105/com.srimanjavagroup.sjg E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.srimanjavagroup.sjg, PID: 14105
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ProgressBar.setVisibility(int)' on a null object reference
MainActivity.java
package com.srimanjavagroup.sjg;
import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Build;
import android.support.annotation.RequiresApi;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.ProgressBar;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
private WebView webView;
private ProgressBar progress;
@RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN)
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
progress = (ProgressBar) findViewById(R.id.progressBar);
//progress.setVisibility(View.GONE);
final String ua = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.77 Safari/537.36";
setContentView(R.layout.activity_main);
webView = (WebView)findViewById(R.id.webView);
//webView.setWebViewClient(new myWebclient());
WebSettings webSettings = webView.getSettings();
webSettings.setJavaScriptEnabled(true);
webSettings.setGeolocationEnabled(true);
webSettings.setUserAgentString(ua);
webSettings.setAllowUniversalAccessFromFileURLs(true);
if(isNetworkAvailable()) {
webView.loadUrl("http://www.srimanjavagroup.com");
webView.setWebViewClient(new WebViewClient(){
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
webView.loadUrl("file:///android_asset/error.html");
Toast.makeText(getApplicationContext(), "Internet is not available", Toast.LENGTH_SHORT).show();
}
@Override
public void onPageFinished(WebView view, String url) {
progress.setVisibility(View.GONE);
super.onPageFinished(view, url);
}
@Override
public void onPageStarted(WebView view, String url, Bitmap favicon) {
progress.setVisibility(View.VISIBLE);
super.onPageStarted(view, url, favicon);
}
@Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
view.loadUrl(url);
return super.shouldOverrideUrlLoading(view, url);
}
});
} else{
webView.loadUrl("file:///android_asset/error.html");
Toast.makeText(getApplicationContext(), "Internet is not available", Toast.LENGTH_SHORT).show();
}
}
@Override
protected void onNewIntent(Intent intent) {`enter code here`
super.onNewIntent(intent);
Log.d("","Notification pass");
Toast.makeText(getApplicationContext(), "notification test", Toast.LENGTH_LONG).show();
}
private boolean isNetworkAvailable() {
ConnectivityManager connectivityManager
= (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
return activeNetworkInfo != null && activeNetworkInfo.isConnected();
}
@Override
public void onBackPressed() {
if(webView.canGoBack()) {
webView.goBack();
} else {
super.onBackPressed();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
main_activity.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<ProgressBar
android:id="@+id/progressBar"
style="?android:attr/progressBarStyle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:layout_width="wrap_content" />
<WebView
android:id="@+id/webView"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_alignParentStart="true"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_alignParentEnd="true"
android:layout_alignParentRight="true"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
</WebView>
</android.support.constraint.ConstraintLayout>
I can't figure out why I'm getting the NullPointerException, looking over the code, everything seems how it should be.
I feel like I'm about to learn something new here because I cleaned the project, tried it out and error keeps occurring regardless.. so I'm not sure what I'm missing.
