GridView en Android

--------------------- Adapter ---------------------

package com.example.visorimagenes;
import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
public class ImagenAdapter extends BaseAdapter {
 private Context mContext;
 public ImagenAdapter(Context c) {
  mContext = c;
 }
 public int getCount() {
  return mThumbIds.length;
 }
 public Object getItem(int position) {
  return null;
 }
 public long getItemId(int position) {
  return 0;
 }
 // create a new ImageView for each item referenced by the Adapter
 @Override
 public View getView(int position, View convertView, ViewGroup parent) {
  ImageView imageView;
  if (convertView == null) { // if it's not recycled, initialize some
         // attributes
   imageView = new ImageView(mContext);
   imageView.setLayoutParams(new GridView.LayoutParams(85, 85));
   imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
   imageView.setPadding(8, 8, 8, 8);
  } else {
   imageView = (ImageView) convertView;
  }
  imageView.setImageResource(mThumbIds[position]);
  return imageView;
 }
 // references to our images
 private Integer[] mThumbIds = { R.drawable.image1, R.drawable.image2,
   R.drawable.image3, R.drawable.image4, R.drawable.image5};
}


---------------------Activity---------------------

package com.example.visorimagenes;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.GridView;
import android.widget.Toast;
public class MainActivity extends Activity  {


 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.menugrid);

  GridView gridview = (GridView) findViewById(R.id.gridview);
  gridview.setStretchMode(GridView.STRETCH_COLUMN_WIDTH);
  gridview.setColumnWidth(90);
//  gridview.setNumColumns(GridView.AUTO_FIT);
  gridview.setNumColumns(3);
  gridview.setAdapter(new ImagenAdapter(this));   

  gridview.setOnItemClickListener(new OnItemClickListener() {
   @Override
   public void onItemClick(AdapterView<?> arg0, View arg1, int position,
     long arg3) {
    // TODO Auto-generated method stub
    Toast.makeText(MainActivity.this, "" + position, Toast.LENGTH_SHORT).show();
 
   }
   });

 }
 @Override
 public boolean onCreateOptionsMenu(Menu menu) {
  // Inflate the menu; this adds items to the action bar if it is present.
  getMenuInflater().inflate(R.menu.activity_main, menu);
  return true;
 }
}



XML MENUOPCIONES

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android" >
    <item android:id="@+id/menu_opcion1"
        android:title="Opcion1"
        android:icon="@drawable/image1"></item>   
    <item android:id="@+id/menu_opcion2"
        android:title="Opcion 2"
        android:icon="@drawable/image2"></item>   
    <item android:id="@+id/menu_opcion3"
        android:title="Opcion 3"
        android:icon="@drawable/image3"></item>  
</menu>


Agregar metodos

@Override
 public boolean onCreateOptionsMenu(Menu menu) {
  // Inflate the menu; this adds items to the action bar if it is present.
  getMenuInflater().inflate(R.menu.menuopciones, menu);
  return true;
 }

 @Override
 public boolean onOptionsItemSelected(MenuItem item) {
  // TODO Auto-generated method stub
  switch (item.getItemId()) {
  case R.id.menu_opcion1:
   Toast.makeText(MainActivity.this, "Menu Opcion 1",Toast.LENGTH_SHORT).show();  
   break;
  case R.id.menu_opcion2:
   Toast.makeText(MainActivity.this, "Menu Opcion 1",Toast.LENGTH_SHORT).show();  
   break;
  case R.id.menu_opcion3:
   Toast.makeText(MainActivity.this, "Menu Opcion 1",Toast.LENGTH_SHORT).show();  
   break;
  default:
   break;
  }
  return false;
  //return super.onOptionsItemSelected(item);
 
 }