android - Add a Progress Bar in WebView

Question

I am trying to add a progress/loading bar to my application that uses WebView. I am confused on how to implement a progress bar that appears every time a link is clicked.

Current code:

public class CULearnBrowser extends Activity {

    WebView webview;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        webview = (WebView) findViewById(R.id.webview);
        webview.setWebViewClient(new HelloWebViewClient());
        webview.getSettings().setJavaScriptEnabled(true);
        webview.loadUrl("https://culearn.colorado.edu/webct/entryPageIns.dowebct");
    }

    private class HelloWebViewClient extends WebViewClient {
        @Override
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            view.loadUrl(url);
            return true;
        }
    }

    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if ((keyCode == KeyEvent.KEYCODE_BACK) && webview.canGoBack()) {
            webview.goBack();
            return true;
        }
        return super.onKeyDown(keyCode, event);
    }
}

Activity layout:

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">

    <WebView  xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/webview"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" />

    <TextView  
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" 
        android:text="@string/hello" />
</LinearLayout>

Answer 1

I have added few lines in your code and now its working fine with progress bar.

        getWindow().requestFeature(Window.FEATURE_PROGRESS);
        setContentView(R.layout.main );
        // Makes Progress bar Visible
        getWindow().setFeatureInt( Window.FEATURE_PROGRESS, Window.PROGRESS_VISIBILITY_ON);

        webview = (WebView) findViewById(R.id.webview);
        webview.setWebChromeClient(new WebChromeClient() {
            public void onProgressChanged(WebView view, int progress)   
            {
                //Make the bar disappear after URL is loaded, and changes string to Loading...
                setTitle("Loading...");
                setProgress(progress * 100); //Make the bar disappear after URL is loaded
     
                // Return the app name after finish loading
                if(progress == 100)
                   setTitle(R.string.app_name);
                }
            });
        webview.setWebViewClient(new HelloWebViewClient());
        webview.getSettings().setJavaScriptEnabled(true);
        webview.loadUrl("http://www.google.com");