How to show web view with Navigation Drawer in android
<p>I am trying to show web view with navigation drawer in android. I am also implementing this but web view listener is not working. </p>

<p><strong>This is my main Activity.</strong></p>

<pre><code> @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
            NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
            navigationView.setNavigationItemSelectedListener(this);
            View headerLayout = navigationView.getHeaderView(0);
            lv = (ListView) headerLayout.findViewById(R.id.listView);
            lv.setAdapter(new CustomAdapter(this, prgmNameList, prgmImages));
            Button button = (Button) findViewById(R.id.btbn);
            button.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Toast.makeText(getApplicationContext(), "click", Toast.LENGTH_SHORT).show();
                }
            });
            webview = (WebView) findViewById(R.id.contaner);
            WebSettings settings = webview.getSettings();
            settings.setJavaScriptEnabled(true);
            webview.setScrollBarStyle(WebView.SCROLLBARS_OUTSIDE_OVERLAY);
            final AlertDialog alertDialog = new AlertDialog.Builder(this).create();
            progressBar = ProgressDialog.show(MainActivity.this, "WebView Example", "Loading...");
            webview.setWebViewClient(new WebViewClient() {
                public boolean shouldOverrideUrlLoading(WebView view, String url) {
                    Log.i(TAG, "Processing webview url click...");
                    view.loadUrl(url);
                    return true;
                }

                public void onPageFinished(WebView view, String url) {
                    Log.i(TAG, "Finished loading URL: " + url);
                    if (progressBar.isShowing()) {
                        progressBar.dismiss();
                    }
                }

                public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
                    Log.e(TAG, "Error: " + description);
                    Toast.makeText(getApplicationContext(), "Oh no! " + description, Toast.LENGTH_SHORT).show();

                }
            });
            webview.loadUrl("https://www.google.co.in/maps?source=tldsi&amp;hl=en");
        }

        @Override
        public void onBackPressed() {
            DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
            if (drawer.isDrawerOpen(GravityCompat.START)) {
                drawer.closeDrawer(GravityCompat.START);
            } 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.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);
        }

        @SuppressWarnings("StatementWithEmptyBody")
        @Override
        public boolean onNavigationItemSelected(MenuItem item) {
            // Handle navigation view item clicks here.
            int id = item.getItemId();
            if (id == R.id.nav_camera) {
                // Handle the camera action
            } else if (id == R.id.nav_gallery) {
            } else if (id == R.id.nav_slideshow) {
            } else if (id == R.id.nav_manage) {
            } else if (id == R.id.nav_share) {
            } else if (id == R.id.nav_send) {
            }
            DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
            drawer.closeDrawer(GravityCompat.START);
            return true;
        }
</code></pre>

<p><strong>And this is layout file</strong> </p>

<pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;RelativeLayout 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"&gt;


    &lt;WebView
        android:id="@+id/contaner"
        android:layout_width="match_parent"
        android:layout_height="match_parent"&gt;&lt;/WebView&gt;

    &lt;Button
        android:id="@+id/btbn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Click"/&gt;

    &lt;android.support.v4.widget.DrawerLayout
        android:id="@+id/drawer_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fitsSystemWindows="true"
        tools:openDrawer="start"&gt;


        &lt;android.support.design.widget.NavigationView
            android:id="@+id/nav_view"
            android:layout_width="100dp"
            android:layout_height="wrap_content"
            android:layout_gravity="start"
            android:fitsSystemWindows="true"
            app:headerLayout="@layout/nav_header_main"
            /&gt;
    &lt;/android.support.v4.widget.DrawerLayout&gt;
&lt;/RelativeLayout&gt;
</code></pre>

<p>Any help, suggestion, tutorials would be highly appreciated. Thank you....</p>