Open html file located inside my application using WebView

Put the file in your /assets directory and use:

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

First you copy the index.html file to assets folder in your project and then try this, It might help you

public class WebViewDemoActivity extends Activity {  

    private WebView mWebView;  
    @Override  
    public void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);

        setContentView(R.layout.web_view_layout);  

        mWebView = (WebView) findViewById(R.id.web_view_id);  
        mWebView.loadUrl("file:///android_asset/index.html");  
    }  
}