page.title=Web View parent.title=Hello, Views parent.link=index.html @jd:body

{@link android.webkit.WebView} allows you to create your own window for viewing web pages (or even develop a complete browser). In this tutorial, you'll create a simple {@link android.app.Activity} that can view and navigate web pages.

  1. Create a new project named HelloWebView.
  2. Open the res/layout/main.xml file and insert the following: 
    <?xml version="1.0" encoding="utf-8"?>
<WebView  xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/webview"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
/>
  3. Now open the HelloWebView.java file. At the top of the class, declare a {@link android.webkit.WebView} object: 
    WebView mWebView;

    Then use the following code for the {@link android.app.Activity#onCreate(Bundle) onCreate()} method:

    public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    mWebView = (WebView) findViewById(R.id.webview);
    mWebView.getSettings().setJavaScriptEnabled(true);
    mWebView.loadUrl("http://www.google.com");
}

    This initializes the member {@link android.webkit.WebView} with the one from the {@link android.app.Activity} layout; requests a {@link android.webkit.WebSettings} object with {@link android.webkit.WebView#getSettings()}; and enables JavaScript for the {@link android.webkit.WebView} with {@link android.webkit.WebSettings#setJavaScriptEnabled(boolean)}. Finally, an initial web page is loaded with {@link android.webkit.WebView#loadUrl(String)}.

  4. Because this application needs access to the Internet, you need to add the appropriate permissions to the Android manifest file. Open the AndroidManifest.xml file and add the following as a child of the <manifest> element: 
    <uses-permission android:name="android.permission.INTERNET" />
  5. While you're in the manifest, give some more space for web pages by removing the title bar, with the "NoTitleBar" theme: 
    <activity android:name=".HelloGoogleMaps" android:label="@string/app_name"
     android:theme="@android:style/Theme.NoTitleBar">
  6. Now run the application.

    You now have a simplest web page viewer. It's not quite a browser yet because as soon as you click a link, the default Android Browser handles the Intent to view a web page, because this {@link android.app.Activity} isn't technically enabled to do so. Instead of adding an intent filter to view web pages, you can override the {@link android.webkit.WebViewClient} class and enable this {@link android.app.Activity} to handle its own URL requests.

  7. In the HelloAndroid Activity, add this nested class: 
    private class HelloWebViewClient extends WebViewClient {
    @Override
    public boolean shouldOverrideUrlLoading(WebView view, String url) {
        view.loadUrl(url);
        return true;
    }
}
  8. Then towards the end of the {@link android.app.Activity#onCreate(Bundle)} method, set an instance of the HelloWebViewClient as the {@link android.webkit.WebViewClient}: 
    mWebView.setWebViewClient(new HelloWebViewClient());

    This line can go anywhere following the initialization of the {@link android.webkit.WebView} object.

    This creates a {@link android.webkit.WebViewClient} that will load any URL selected from this {@link android.webkit.WebView} into the same {@link android.webkit.WebView}. The {@link android.webkit.WebViewClient#shouldOverrideUrlLoading(WebView,String)} method is passed the current {@link android.webkit.WebView} and the URL requested, so all it needs to do is load the URL in the given view. Returning true says that the method has handled the URL and the event should not propagate (in which case, an Intent would be created that's handled by the Browser application).

    If you run the application again, new pages will now load in this Activity. However, you can't navigate back to previous pages. To do this, you need to handle the BACK button on the device, so that it will return to the previous page, rather than exit the application.

  9. To handle the BACK button key press, add the following method inside the HelloWebView Activity: 
     
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if ((keyCode == KeyEvent.KEYCODE_BACK) && mWebView.canGoBack()) {
        mWebView.goBack();
        return true;
    }
    return super.onKeyDown(keyCode, event);
}

    This {@link android.app.Activity#onKeyDown(int,KeyEvent)} callback method will be called anytime a button is pressed while in the Activity. The condition inside uses the {@link android.view.KeyEvent} to check whether the key pressed is the BACK button and whether the {@link android.webkit.WebView} is actually capable of navigating back (if it has a history). If both are true, then the {@link android.webkit.WebView#goBack()} method is called, which will navigate back one step in the {@link android.webkit.WebView} history.Returning true indicates that the event has been handled. If this condition is not met, then the event is sent back to the system.

  10. Run the application again. You'll now be able to follow links and navigate back through the page history.

When you open the application, it should look like this:

Resource