Java 主菜单未出现在我的Android手机上

我正在尝试设置主菜单，但它没有出现在我的手机上。主菜单xml已经设置好，所有内容都已编译，但当我在手机上尝试时，它没有出现。构建目标是安卓4.0.3，和我的手机一样。下面是java代码，希望有人能帮我

    package image.change;

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

    public class UserInterface extends Activity {

        @Override
        public void onCreate(Bundle savedInstanceState) {

            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);

        }//end onCreate

        @Override
        public boolean onCreateOptionsMenu(Menu menu) {

            MenuInflater inflater = getMenuInflater();
            inflater.inflate(R.menu.mainmenu, menu);
            return true;

        }//end onCreateOptionsMenu

    }//end UserInterface

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尝试此操作以构建您的

菜单

@Override
    public boolean onCreateOptionsMenu(Menu menu){
        boolean result=super.onCreateOptionsMenu(menu);
        menu.add(0,menu_1,1,"Register");
        return result;
    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item){
        switch(item.getItemId()){       
            case menu_1:
                fnRegistration();
                return true;
        }         
        return super.onOptionsItemSelected(item);
    }

试着这样做

对菜单进行充气：

 public boolean onCreateOptionsMenu(Menu menu)
    {
        MenuInflater menuInflater = getMenuInflater();
        menuInflater.inflate(R.layout.menu, menu);
        return true;
    }

public boolean onOptionsItemSelected(MenuItem item)
    {

        switch (item.getItemId())
        {
        case R.id.menu_bookmark:
            // Single menu item is selected do something
            // Ex: launching new activity/screen or show alert message
            Toast.makeText(AndroidMenusActivity.this, "Bookmark is Selected", Toast.LENGTH_SHORT).show();
            return true;

        case R.id.menu_save:
            Toast.makeText(AndroidMenusActivity.this, "Save is Selected", Toast.LENGTH_SHORT).show();
            return true;

        case R.id.menu_search:
            Toast.makeText(AndroidMenusActivity.this, "Search is Selected", Toast.LENGTH_SHORT).show();
            return true;

        case R.id.menu_share:
            Toast.makeText(AndroidMenusActivity.this, "Share is Selected", Toast.LENGTH_SHORT).show();
            return true;

        case R.id.menu_delete:
            Toast.makeText(AndroidMenusActivity.this, "Delete is Selected", Toast.LENGTH_SHORT).show();
            return true;

        case R.id.menu_preferences:
            Toast.makeText(AndroidMenusActivity.this, "Preferences is Selected", Toast.LENGTH_SHORT).show();
            return true;

        default:
            return super.onOptionsItemSelected(item);
        }
    }    

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当你按下手机的功能表按钮时，发生了什么？