Trouble loading random image on button press

What i'm trying to do is just simply have the button load an image at random. However, the button doesn't seem to be working. When i first load the activity there it works fine and there is a random image....But when i press the button it's not loading another like i need it to. Any idea what i have wrong here? It looks fine to me :/

package com.my.package;


import java.util.Random;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import a开发者_JS百科ndroid.view.View;
import android.widget.ImageView;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View.OnClickListener;

public class Randomimage extends Activity implements OnClickListener{


    private Integer [] mImageIds = { 
            R.drawable.one, 
            R.drawable.two, 
            R.drawable.three, 
            };
    private static final Random rgenerator = new Random();

    private ImageView iv;



@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);


    Integer q = mImageIds[rgenerator.nextInt(mImageIds.length)];

    iv = (ImageView) findViewById(R.id.imageviewyeah);
    iv.setImageResource(q);


    View nextButton = findViewById(R.id.next_image_button);
    nextButton.setOnClickListener(this);

}


    @Override
    public void onClick(View v) {
    switch (v.getId()) {
    case R.id.next_image_button:
        iv.setImageResource(rgenerator.nextInt(mImageIds.length));
        break;
    }

}
    @Override
    public boolean onCreateOptionsMenu (Menu menu) {
        super.onCreateOptionsMenu(menu);
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.menu3, menu);
        return true;
    }

@Override
public boolean onOptionsItemSelected (MenuItem item) {
        switch (item.getItemId()) {
        case R.id.menu:
            startActivity(new Intent(this, Main.class));
            return true;
        case R.id.startnhie:
            startActivity(new Intent(this, startnhie.class));
            return true;

}
return false;
    }



}

In your button press handling code, change

iv.setImageResource(rgenerator.nextInt(mImageIds.length));

to

iv.setImageResource(mImageIds[rgenerator.nextInt(mImageIds.length)]);