WebView with back button opening dialog

I am creating an application that opens a url inside a webview. Then when the back button is pressed this opens up a dialog asking the user if they are sure if they want to quit. Although the dialog works properly, the app will not load the website, and now I have errors so I can't even compile when I put in the HelloWebViewClient. Anything you suggest? Thanks!

Here's my code:

package de.vogella.android.alertdialog;





import android.app.Activity;
import android.app.AlertDialog;
import android.app.AlertDialog.Builder;
import android.app.Dialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
import android.widget.Toast;
import android.webkit.WebView;
import android.webkit.WebViewClient;

public class ShowMyDialog extends Activity {
    private WebView webview;

    /** Called when the activity is first created. */
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if ((keyCode == KeyEvent.KEYCODE_BACK)) {
            openMyDialog(null);
            return true;
        }
        return super.onKeyDown(keyCode, event);
    }




    @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.setInitialScale(50); 
        webview.getSettings().setUseWideViewPort(true); 
        webview.loadUrl("http://mdsitest2.com/");
    }
    private class HelloWebViewClient extends WebViewClient {

        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            view.loadUrl(url);
开发者_开发技巧            return true;


            }







    public void openMyDialog(View view) {
        showDialog(10);
    }

    @Override
    protected Dialog onCreateDialog(int id) {
        switch (id) {
        case 10:
            // Create our AlertDialog
            Builder builder = new AlertDialog.Builder(this);
            builder.setMessage("Are you sure you want to exit?")
                    .setCancelable(true)
                    .setPositiveButton("Yes",
                            new DialogInterface.OnClickListener() {
                                @Override
                                public void onClick(DialogInterface dialog,
                                        int which) {
                                    // Ends the activity
                                    ShowMyDialog.this.finish();
                                }
                            })
                    .setNegativeButton("Keep Guessing!",
                            new DialogInterface.OnClickListener() {

                                @Override
                                public void onClick(DialogInterface dialog,
                                        int which) {
                                    Toast.makeText(getApplicationContext(),
                                            "Good Luck!",
                                            Toast.LENGTH_SHORT).show();
                                }
                            });


            AlertDialog dialog = builder.create();
            dialog.show();

        }
        return super.onCreateDialog(id);
    }
}

XML:

<?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_height="fill_parent" android:layout_width="fill_parent" android:scrollbarAlwaysDrawVerticalTrack="false"/>




</LinearLayout>

Try overriding the the onBackPressed button instead of doing it via onKeyDown. Also implement the comment Pixie made...