android exam: WebView android exam

The WebView view allows you to embed a web browser in your Android applications. Add a new file to the res/layout folder and name it as webview.xml and populate it with the following element:

<?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 android:id="@+id/webview1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" 
        android:text = "Hello, world!"
        />            
 
</LinearLayout>

Add a new class to the src/net.learn2develop.AndroidViews folder and name it as WebViewExample.java. Populate it as follows:

package net.learn2develop.AndroidViews;
 
import android.app.Activity;
import android.os.Bundle;
import android.webkit.WebView;
 
public class WebViewExample extends Activity
{
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.webview);
 
        WebView wv = (WebView) findViewById(R.id.webview1);        
        wv.loadUrl("http://www.mobiforge.com");  
    }
}

The loadUrl() method of the WebView class loads the page of a given URL. Modify the AndroidManifest.xml file to register the new activity as well as to request for the INTERNET permission:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="net.learn2develop.AndroidViews"
      android:versionCode="1"
      android:versionName="1.0.0">
    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".ViewsActivity" 
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
 
        <activity android:name=".WebViewExample"
                  android:label="@string/app_name" />
 
    </application>
 
    <uses-permission android:name="android.permission.INTERNET">
    </uses-permission>
 
   <uses-sdk android:minSdkVersion="3" />
 
</manifest>

For the WebView view to work, you need to add the INTERNET permission to the AndroidManifest.xml file. Modify the ViewsActivity.java file as follows to start the WebViewExample activity:

package net.learn2develop.AndroidViews;
 
import android.app.Activity;
import android.os.Bundle;
import android.content.Intent;
 
public class ViewsActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);      
        startActivity(new Intent(this, WebViewExample.class));
    }
}

Press F11 to debug the application on the Android emulator. Figure 8 shows the WebView view in action.

Figure 8 - The WebView displaying a web page

You can also dynamically formulate a HTML string and load it into the WebView view, using the loadDataWithBaseURL() method:

 
  WebView wv = (WebView) findViewById(R.id.webview1);        
 
        final String mimeType = "text/html";
        final String encoding = "UTF-8";
        String html = "<H1>A simple HTML page</H1><body>" +
            "<p>The quick brown fox jumps over the lazy dog</p>"; 
 
        wv.loadDataWithBaseURL("", html, mimeType, encoding, "");

Figure 9 shows the WebView with the HTML string loaded.

Figure 9 - Displaying the content of a HTML string

If you have static pages that you want to load directly from your project, you can save the HTML pages under the assets folder of your package. Figure 10 shows that I have added a page named Index.html under the assets folder.

Figure 10 - Adding a HTML page in the assets folder

The content of the Index.html is as follows:

<h1>A simple HTML page</h1>
<body>
   <p>The quick brown fox jumps over the lazy dog</p>
   <img src='http://www.google.com/logos/Logo_60wht.gif'/>
</body>

To load the WebView using the content stored in the Index.html file, use the loadUrl() method as follows:

WebView wv = (WebView) findViewById(R.id.webview1);     
     wv.loadUrl("file:///android_asset/Index.html");

Figure 11 shows the content loaded in the WebView view.

Figure 11 - Loading the HTML page using WebView

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Friday, September 30, 2011

WebView android exam