display map on click of a button in android

hey guys i want to display a map on the click of a button...for this i have implemented 2 classes.one class has a button and an intent call,while the second class displays the map.On running the application the button is getting displayed but on clicking it the application crashes. onclick.java

 
public class onclick extends Activity
{
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        Button btnOpen = (Button) findViewById(R.id.btnSave);
        btnOpen.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
               // TODO Auto-generated method stub
               Intent myIntent=new Intent(onclick.this,a.class);
               startActivity(myIntent);

            }
         });
    }
}

a.java

package com.onclick; 
public class a extends MapActivity{
   private MapView mapView;


@Override
   protected boolean isRouteDisplayed() {
      // TODO Auto-generated method stub
      return false;
   }
   @Override
   public void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   setContentView(R.layout.f);
   mapView = (MapView)findViewById(R.id.map_view);
   mapView.setStreetView(true);
   }
   }

In AndroidManifest.xml i have provided the internet permission,also used com.google.android.maps and the statement <activity android:name=".a"></activity>

guys plzz help me out...any help will be really appreciated

my logcat error 03-06 16:22:41.812: ERROR/AndroidRuntime(219): Uncaught handler: thread main exiting due to uncaught exception

03-06 16:22:41.883: ERROR/AndroidRuntime(219): java.lang.NoClassDefFoundError: com.onclick.a

03-06 16:22:41.883: ERROR/AndroidRuntime(219):at com.onclick.onclick$1.onClick(onclick.java:22)

03-06 16:22:41.883: ERROR/AndroidRuntime(219):at android.view.View.performClick(View.java:2364)

03-06 16:22:41.883: ERROR/AndroidRuntime(219)at android.view.View.onTouchEvent(View.java:4179) 03-06 16:22:41.883: ERROR/AndroidRuntime(219): at android.widget.TextView.onTouchEvent(TextView.java:6540)

03-06 16:22:41.883: ERROR/AndroidRuntime(219): at android.view.View.dispatchTouchEvent(View.java:3709)

03-06 16:22:41.883: ERROR/AndroidRuntime(219):at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)

03-06 16:22:41.883: ERROR/AndroidRuntime(219): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)

03-06 16:22:41.883: ERROR/AndroidRuntime(219):at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)

03-06 16:22:41.883: ERROR/AndroidRuntime(219):at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)

03-06 16:22:41.883: ERROR/AndroidRuntime(219):at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1659)

03-06 16:22:41.883: ERROR/AndroidRuntime(219):at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1107)

03-06 16:22:41.883: ERROR/AndroidRuntime(219):at android.app.Activity.dispatchTouchEvent(Activity.java:2061)

03-06 16:22:41.883: ERROR/AndroidRuntime(219):at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1643)

03-06 16:22:41.883: ERROR/AndroidRuntime(219): at android.view.ViewRoot.handleMessage(ViewRoot.java:1691)

03-06 16:22:41.883: ERROR/AndroidRuntime(219): at android.os.Handler.dispatchMessage(Handler.java:99)

03-06 16:22:41.883: ERROR/AndroidRuntime(219): at android.os.Looper.loop(Looper.java:123)

03-06 16:22:41.883: ERROR/AndroidRuntime(219): at android.app.ActivityThread.main(ActivityThread.java:4363)

03-06 16:22:41.883: ERROR/AndroidRuntime(219): at java.lang.reflect.Method.invokeNative(Native Method)

03-06 16:22:41.883: ERROR/AndroidRuntime(219):at java.lang.reflect.Method.invoke(Method.java:521)

03-06 16:22:41.883: ERROR/AndroidRuntime(219): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)

03-06 16:22:41.883: ERROR/AndroidRuntime(219):at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)

03-06 16:22:41.883: ERROR/AndroidRuntime(219):at dalvik.system.NativeStart.main(Native Method)

确保你的包名在你的清单和所有java文件中都是正确的