[新人求助]关于Dialog中imageView的onClic

在Dialog中的imageView的onClick怎么实现？
package com.mycompany.myapp2;
import android.app.*;
import android.os.*;
import android.view.*;
import android.widget.*;
public class MainActivity extends Activity
{
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
public void di(View view)
{
Dialog dialog = new Dialog(MainActivity.this,R.style.MyDialog);
//设置它的ContentView
dialog.setContentView(R.layout.main2);
dialog.show();
dialog.setCancelable(false);
}
public void exit(){
finish();
}
}
这是代码，在main2.xml中我只设置了一个imageView，其中onClick事件是exit,怎么还是出错？