动态增添代码

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

/**
 * Class which shows how to change dynamically options menu items
 * @author FaYnaSoft Labs
 */
public class Main extends Activity {

    private Button clickBtn;
    private boolean isChangedStat = false;
    private static final int MENUITEM = Menu.FIRST;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        clickBtn = (Button) findViewById(R.id.click);
        clickBtn.setText("Click me");
        clickBtn.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                if (isChangedStat) {
                    isChangedStat = false;
                } else {
                    isChangedStat = true;
                }
            }
        });
    }

    @Override
    public boolean onPrepareOptionsMenu(Menu menu) {
        menu.clear();
        if (isChangedStat) {
            menu.add(0, MENUITEM, 0, "True");
        } else {
            menu.add(0, MENUITEM, 0, "False");
        }
        return super.onPrepareOptionsMenu(menu);
    }
}