Null pointer Exception when compiling

Question

I have developed an simple webview app from android stuido that will load url of page when online and show cache file when offline. But I'm getting a constant error of

 Null pointer Exception
    at java.lang.reflect.Method.invoke(Native Method)                                                                           
atcom.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit
.java:726)                                                                                 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

and Below is my Code from Mainactivity .java

package com.example.sagar.cdproutine;

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.webkit.WebSettings;
import android.webkit.WebView;

public class MainActivity extends AppCompatActivity {

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

        Context context = null;
        WebView webView = new WebView(context);
        webView.getSettings().setAppCacheMaxSize(5 * 1024 * 1024); // 5MB
        webView.getSettings().setAppCachePath(
            getApplicationContext().getCacheDir().getAbsolutePath());
        webView.getSettings().setAllowFileAccess(true);
        webView.getSettings().setAppCacheEnabled(true);
        webView.getSettings().setJavaScriptEnabled(true);
        webView.getSettings().setCacheMode(WebSettings.LOAD_DEFAULT); // load online by default

        if (!isNetworkAvailable()) { // loading offline
            webView.getSettings().setCacheMode(
                WebSettings.LOAD_CACHE_ELSE_NETWORK);
        }

        webView.loadUrl("http://www.sagarrawal.com.np");
    }

    private boolean isNetworkAvailable() {
        ConnectivityManager connectivityManager = (ConnectivityManager)
        getSystemService(CONNECTIVITY_SERVICE);
        NetworkInfo activeNetworkInfo =
            connectivityManager.getActiveNetworkInfo();
        return activeNetworkInfo != null;
    }
}

and from my manifest.xml file

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.sagar.cdproutine">

<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"/>

I think Context is causing the problem but I don't know how to resolve it. Any Help would be largely appreciated.

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

Answer 1

Am i missing something? This line right here is null and your passing it to web view.

Context context = null;

Try something like this:

WebView webView = new WebView( getApplicationContext());

Answer 2

As David mentioned don't pass null Context

This is in OnCreate

webView = (WebView) findViewById(R.id.webView);
initWebView();//Initialize the WebView
webView.loadUrl(url);//pass your Url

And for initWebView();

private void initWebView() {
    webView.setWebChromeClient(new MyWebChromeClient(this));
    webView.setWebViewClient(new WebViewClient() {
        @Override
        public void onPageStarted(WebView view, String url, Bitmap favicon) {
            super.onPageStarted(view, url, favicon);        
        }

        @Override
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            webView.loadUrl(url);
            return true;
        }

        @Override
        public void onPageFinished(WebView view, String url) {
            super.onPageFinished(view, url);
        }

        @Override
        public void onReceivedError(WebView view, WebResourceRequest request, WebResourceError error) {
            super.onReceivedError(view, request, error);
        }
    });
    webView.clearCache(true);
    webView.clearHistory();
    webView.getSettings().setJavaScriptEnabled(true);
    webView.setHorizontalScrollBarEnabled(false);
}

For MyWebChromeClient do this:

private class MyWebChromeClient extends WebChromeClient {
    Context context;

    public MyWebChromeClient(Context context) {
        super();
        this.context = context;
    }


}

Also look at this reference- link