Android ActionProvider sample.

app_pick_action.xml

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">

	<item android:id="@+id/pick_action_provider"
		android:showAsAction="always" android:title="@string/pick_action"
		android:actionProviderClass="net.vvakame.sapmle.AppPickActionProvider" />

</menu>

AppPickActionProvider.java

package net.vvakame.sapmle;

import java.util.List;

import android.content.Context;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.util.Log;
import android.view.ActionProvider;
import android.view.Menu;
import android.view.MenuItem;
import android.view.MenuItem.OnMenuItemClickListener;
import android.view.SubMenu;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;

public class AppPickActionProvider extends ActionProvider implements
		OnMenuItemClickListener {

	static final int LIST_LENGTH = 3;

	Context mContext;

	public AppPickActionProvider(Context context) {
		super(context);
		mContext = context;
	}

	@Override
	public View onCreateActionView() {
		Log.d(this.getClass().getSimpleName(), "onCreateActionView");

		TextView textView = new TextView(mContext);
		textView.setText("Pick");

		return null; // null を返してもいい
	}

	@Override
	public boolean onPerformDefaultAction() {
		Log.d(this.getClass().getSimpleName(), "onPerformDefaultAction");

		return super.onPerformDefaultAction();
	}

	@Override
	public boolean hasSubMenu() {
		Log.d(this.getClass().getSimpleName(), "hasSubMenu");

		return true;
	}

	@Override
	public void onPrepareSubMenu(SubMenu subMenu) {
		Log.d(this.getClass().getSimpleName(), "onPrepareSubMenu");

		subMenu.clear();

		PackageManager manager = mContext.getPackageManager();
		List<ApplicationInfo> applicationList = manager
				.getInstalledApplications(PackageManager.GET_ACTIVITIES);

		for (int i = 0; i < Math.min(LIST_LENGTH, applicationList.size()); i++) {
			ApplicationInfo appInfo = applicationList.get(i);

			subMenu.add(0, i, i, manager.getApplicationLabel(appInfo))
					.setIcon(appInfo.loadIcon(manager))
					.setOnMenuItemClickListener(this);
		}

		if (LIST_LENGTH < applicationList.size()) {
			subMenu = subMenu.addSubMenu(Menu.NONE, LIST_LENGTH, LIST_LENGTH,
					"hoge");

			for (int i = 0; i < applicationList.size(); i++) {
				ApplicationInfo appInfo = applicationList.get(i);

				subMenu.add(0, i, i, manager.getApplicationLabel(appInfo))
						.setIcon(appInfo.loadIcon(manager))
						.setOnMenuItemClickListener(this);
			}
		}
	}

	@Override
	public boolean onMenuItemClick(MenuItem item) {
		Toast.makeText(mContext, item.getTitle(), Toast.LENGTH_SHORT).show();
		return true;
	}
}

MainActivity.java

package net.vvakame.sapmle;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;

public class MainActivity extends Activity {

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

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		super.onCreateOptionsMenu(menu);

		{
			MenuInflater inflater = new MenuInflater(this);
			inflater.inflate(R.menu.app_pick_action, menu);
		}

		return true;
	}
}

thanks!