How to use webview in android?

MainActivity.java

package com.swain.cell.financial.calculator;

import android.os.Bundle;

import android.app.Activity;

import android.view.Menu;

import android.webkit.WebView;

public class MainActivity extends Activity {

               

                WebView wv;

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        wv=(WebView)findViewById(R.id.webView1);

       wv.getSettings().setJavaScriptEnabled(true);

        wv.loadUrl("file:///android_asset/playlist/index.html");

       

    }

    @Override

    public boolean onCreateOptionsMenu(Menu menu) {

        getMenuInflater().inflate(R.menu.activity_main, menu);

        return true;

    }

}

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent" >

    <TextView

        android:id="@+id/textView1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignParentTop="true"

        android:layout_centerHorizontal="true"

        android:text="@string/hello_world"

        tools:context=".MainActivity" />

    <WebView

        android:id="@+id/webView1"

        android:layout_width="match_parent"

        android:layout_height="match_parent"

        android:layout_alignParentLeft="true"

        android:layout_below="@+id/textView1" />

</RelativeLayout>

AndroidManifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

    package="com.swain.cell.financial.calculator"

    android:versionCode="1"

    android:versionName="1.0" >

    <uses-sdk

        android:minSdkVersion="3"

        android:targetSdkVersion="15" />

    <application

        android:icon="@drawable/ic_launcher"

        android:label="@string/app_name"

        android:theme="@style/AppTheme" >

        <activity

            android:name=".MainActivity"

            android:label="@string/title_activity_main" >

            <intent-filter>

                <action android:name="android.intent.action.MAIN"/>

                <category android:name="android.intent.category.LAUNCHER"/>

            </intent-filter>

        </activity>

       

    </application>

<uses-permission android:name="android.permission.INTERNET" />

</manifest>