在button 事件中 弹出menu 菜单

package com.android;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;

public class mainActivity extends Activity implements OnClickListener {
private Button button;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

button=(Button)findViewById(R.id.button1);
button.setOnClickListener(this);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
menu.add(0,0,0,"yun");
menu.add(0,1,1,"yu");
return super.onCreateOptionsMenu(menu);
}

@Override
public void openOptionsMenu() {
// TODO Auto-generated method stub
super.openOptionsMenu();
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
int item_id=item.getItemId();
switch (item_id) {
case 0:
Toast.makeText(mainActivity.this, "飘荡的云", Toast.LENGTH_LONG).show();
break;

case 1:
Toast.makeText(mainActivity.this, "飘荡的云", Toast.LENGTH_LONG).show();
break;
}
return true;
}

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
int id=v.getId();
switch (id) {
case R.id.button1:
openOptionsMenu();
break;
}

}
}