java - 从 OnItemClick 扩充菜单

Question

我正在尝试从 OnItemClick 中扩充菜单。我查看了 Android 开发者网站，并能够使用下面的第一个代码来充气 toast 。然而，当我尝试用菜单充气机替换它时，它不起作用。你能帮我解决这个问题吗？第一组代码是可以工作的 toast 充气器，第二组代码是不能工作的菜单充气器。当我点击某个项目时， toast 会弹出，但菜单不会。该程序将无法运行，并说我在菜单充气器中存在多个语法错误。虽然我无法解决它们。

package com.carouseldemo.main;

import com.carouseldemo.controls.Carousel;
import com.carouseldemo.controls.CarouselAdapter;
import com.carouseldemo.controls.CarouselItem;
import com.carouseldemo.controls.CarouselAdapter.OnItemClickListener;
import com.carouseldemo.controls.CarouselAdapter.OnItemSelectedListener;
import com.carouseldemo.main.R;

import android.app.Activity;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;

import android.widget.TextView;
import android.widget.Toast;


public class MainActivity extends Activity implements OnClickListener {
/** Called when the activity is first created. */
 @Override
 public void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     setContentView(R.layout.main);




    MediaPlayer mp = MediaPlayer.create(this, R.raw.radio);
    mp.start();
    Carousel carousel = (Carousel)findViewById(R.id.carousel);
    carousel.setOnItemClickListener(new OnItemClickListener(){

        public void onItemClick(CarouselAdapter<?> parent, View view,
                int position, long id) {    

            LayoutInflater inflater = getLayoutInflater();
            View layout = inflater.inflate(R.layout.toast_layout,
                                           (ViewGroup) findViewById(R.id.toast_layout_root));

            TextView text = (TextView) layout.findViewById(R.id.text);
            text.setText("Welcome to Power Source International");

            Toast toast = new Toast(getApplicationContext());
            toast.setGravity(Gravity.CENTER_VERTICAL, 0, 0);
            toast.setDuration(Toast.LENGTH_LONG);
            toast.setView(layout);

        }



    });




    carousel.setOnItemSelectedListener(new OnItemSelectedListener(){

        public void onItemSelected(CarouselAdapter<?> parent, View view,
                int position, long id) {



            final TextView txt = (TextView)(findViewById(R.id.selected_item));

            switch(position){
            case 0:
                txt.setText("Power Source International ");
                break;
            case 1:
                txt.setText("Power Source International");
                break;
            case 2:
                txt.setText("Power Source International");
                break;
            case 3:
                txt.setText("Power Source International.");
                break;
            case 4:
                txt.setText("Power Source International");
            case 5:
                txt.setText("Power Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source International");
                break;
            }

        }

        public void onNothingSelected(CarouselAdapter<?> parent) {
        }

    }
    );

}

@Override
public void onClick(View v) {
    // TODO Auto-generated method stub

}



}

这可以正常工作。然而，当我尝试膨胀菜单而不是 toast 时，却没有。这是不起作用的代码，并且菜单膨胀器中存在语法错误。无论我尝试做什么，我都无法更正代码。

package com.carouseldemo.main;

import com.carouseldemo.controls.Carousel;
import com.carouseldemo.controls.CarouselAdapter;
import com.carouseldemo.controls.CarouselItem;
import com.carouseldemo.controls.CarouselAdapter.OnItemClickListener;
import com.carouseldemo.controls.CarouselAdapter.OnItemSelectedListener;
import com.carouseldemo.main.R;

import android.app.Activity;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.MenuInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;

import android.widget.TextView;
import android.widget.Toast;


public class MainActivity extends Activity implements OnClickListener {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);




    MediaPlayer mp = MediaPlayer.create(this, R.raw.radio);
    mp.start();
    Carousel carousel = (Carousel)findViewById(R.id.carousel);
    carousel.setOnItemClickListener(new OnItemClickListener(){

        private Object v;

        public void onItemClick(CarouselAdapter<?> parent, View view,
                int position, long id) {    

            @Override
            public void onCreateContextMenu (ContextMenu menu, View v,
                                            ContextMenuInfo menuInfo) {
                super.onCreateContextMenu(menu, v, menuInfo);
                MenuInflater inflater = getMenuInflater();
                inflater.inflate(R.menu.context_menu, menu);
            }

        }



    });




    carousel.setOnItemSelectedListener(new OnItemSelectedListener(){

        public void onItemSelected(CarouselAdapter<?> parent, View view,
                int position, long id) {



            final TextView txt = (TextView)(findViewById(R.id.selected_item));

            switch(position){
            case 0:
                txt.setText("Power Source International ");
                break;
            case 1:
                txt.setText("Power Source International");
                break;
            case 2:
                txt.setText("Power Source International");
                break;
            case 3:
                txt.setText("Power Source International.");
                break;
            case 4:
                txt.setText("Power Source International");
            case 5:
                txt.setText("Power Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source International");
                break;
            }

        }

        public void onNothingSelected(CarouselAdapter<?> parent) {
        }

    }
    );

}

@Override
public void onClick(View v) {
    // TODO Auto-generated method stub

}



}

对此有什么建议吗？先感谢您。

更新的代码:

package com.carouseldemo.main;

import com.carouseldemo.controls.Carousel;
import com.carouseldemo.controls.CarouselAdapter;
import com.carouseldemo.controls.CarouselItem;
import com.carouseldemo.controls.CarouselAdapter.OnItemClickListener;
import com.carouseldemo.controls.CarouselAdapter.OnItemSelectedListener;
import com.carouseldemo.main.R;

import android.app.Activity;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.MenuInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;

import android.widget.TextView;
import android.widget.Toast;


public class MainActivity extends Activity implements OnClickListener {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);




    MediaPlayer mp = MediaPlayer.create(this, R.raw.radio);
    mp.start();
    Carousel carousel = (Carousel)findViewById(R.id.carousel);
    carousel.setOnItemClickListener(new OnItemClickListener(){

        public void onItemClick(CarouselAdapter<?> parent, View view,
                int position, long id) {    
            openContextMenu(view);


        }

        @Override
        public void onCreateContextMenu(ContextMenu menu, View v,
                ContextMenuInfo menuInfo) {

            super.onCreateContextMenu(menu, v, menuInfo);
            MenuInflater inflater = getMenuInflater();
            inflater.inflate(R.menu.context_menu, menu);

            // TODO Auto-generated method stub

        }



    });




    carousel.setOnItemSelectedListener(new OnItemSelectedListener(){

        public void onItemSelected(CarouselAdapter<?> parent, View view,
                int position, long id) {



            final TextView txt = (TextView)(findViewById(R.id.selected_item));

            switch(position){
            case 0:
                txt.setText("Power Source International ");
                break;
            case 1:
                txt.setText("Power Source International");
                break;
            case 2:
                txt.setText("Power Source International");
                break;
            case 3:
                txt.setText("Power Source International.");
                break;
            case 4:
                txt.setText("Power Source International");
            case 5:
                txt.setText("Power Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source International");
                break;
            }

        }

        public void onNothingSelected(CarouselAdapter<?> parent) {
        }

    }
    );

}

@Override
public void onClick(View v) {
    // TODO Auto-generated method stub

}



}

更新2:

package com.carouseldemo.main;

import android.app.Activity;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.MenuInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.TextView;

import com.carouseldemo.controls.Carousel;
import com.carouseldemo.controls.CarouselAdapter;
import com.carouseldemo.controls.CarouselAdapter.OnItemClickListener;
import com.carouseldemo.controls.CarouselAdapter.OnItemSelectedListener;


public class MainActivity extends Activity implements OnClickListener {
 @Override
  public void onCreateContextMenu (ContextMenu menu, View v, ContextMenuInfo menuInfo) {
    super.onCreateContextMenu(menu, v, menuInfo);
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.context_menu, menu);
  }


/** Called when the activity is first created. */

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




    MediaPlayer mp = MediaPlayer.create(this, R.raw.radio);
    mp.start();
    Carousel carousel = (Carousel)findViewById(R.id.carousel);
    carousel.setOnItemClickListener(new OnItemClickListener(){

        public void onItemClick(CarouselAdapter<?> parent, View view,
                int position, long id) {    
            openContextMenu(view);


        }

        @Override
        public void onCreateContextMenu(ContextMenu menu, View v,
                ContextMenuInfo menuInfo) {
            // TODO Auto-generated method stub

        }



    });




    carousel.setOnItemSelectedListener(new OnItemSelectedListener(){

        public void onItemSelected(CarouselAdapter<?> parent, View view,
                int position, long id) {



            final TextView txt = (TextView)(findViewById(R.id.selected_item));

            switch(position){
            case 0:
                txt.setText("Power Source International ");
                break;
            case 1:
                txt.setText("Power Source International");
                break;
            case 2:
                txt.setText("Power Source International");
                break;
            case 3:
                txt.setText("Power Source International.");
                break;
            case 4:
                txt.setText("Power Source International");
            case 5:
                txt.setText("Power Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source InternationalPower Source International");
                break;
            }

        }

        public void onNothingSelected(CarouselAdapter<?> parent) {
        }

    }
    );

}

@Override
public void onClick(View v) {
    // TODO Auto-generated method stub

}



}

Answer 1

您应该尝试将 onCreateContextMenu() 方法移至 Activity 的根目录，如下所示:

public class MainActivity extends Activity implements OnClickListener {

  @Override
  public void onCreateContextMenu (ContextMenu menu, View v, ContextMenuInfo menuInfo) {
    super.onCreateContextMenu(menu, v, menuInfo);
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.context_menu, menu);
  }

  @Override
  public void onCreate(Bundle savedInstanceState) {
    //implementation
  }
  //rest of code
}

那么你可能会想要这样的东西:

 public void onItemClick(CarouselAdapter<?> parent, View view,
                int position, long id) {    
     openContextMenu(view);
 }

请注意，一旦用户点击某个项目，就会弹出上下文菜单。