Question

HIII

我试图创建一个由项目列表组成的上下文菜单。点击弹出菜单中应该出现的任何一项。问题是当我点击该项目时，它仍然保留在同一页面上（即没有显示弹出窗口）...请建议我哪里出错？

代码如下： -

activity_main.xml中

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"  
    xmlns:tools="http://schemas.android.com/tools"  
    android:layout_width="match_parent"  
    android:layout_height="match_parent"  
    android:paddingBottom="@dimen/activity_vertical_margin"  
    android:paddingLeft="@dimen/activity_horizontal_margin"  
    android:paddingRight="@dimen/activity_horizontal_margin"  
    android:paddingTop="@dimen/activity_vertical_margin"  
    tools:context=".MainActivity" >  

    <ListView  
        android:id="@+id/listView1"  
        android:layout_width="match_parent"  
        android:layout_height="wrap_content"  
        android:layout_alignParentLeft="true"  
        android:layout_alignParentTop="true"  
        android:layout_marginLeft="66dp"  
        android:layout_marginTop="53dp" >  
    </ListView>  

</RelativeLayout>

MainActivity.java

package com.javatpoint.contextmenu;  
import android.os.Bundle;  
import android.app.Activity;  
import android.view.ContextMenu;  
import android.view.ContextMenu.ContextMenuInfo;  
import android.view.Menu;  
import android.view.MenuItem;  
import android.view.View;  
import android.widget.AdapterView;  
import android.widget.ArrayAdapter;  
import android.widget.ListView;  
import android.widget.Toast;  

public class MainActivity extends Activity {  
    ListView listView1;  
    String contacts[]={"Ajay","Sachin","Sumit","Tarun","Yogesh"};  

    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.activity_main);  

        listView1=(ListView)findViewById(R.id.listView1);  

        ArrayAdapter<String> adapter=new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,contacts);  
        listView1.setAdapter(adapter);  

        // Register the ListView  for Context menu  
        registerForContextMenu(listView1);  
    }  

    @Override   
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo)  
    {  
            super.onCreateContextMenu(menu, v, menuInfo);  
            menu.setHeaderTitle("Select The Action");    
            menu.add(0, v.getId(), 0, "Call");//groupId, itemId, order, title   
            menu.add(0, v.getId(), 0, "SMS");   
    }   

    @Override    
    public boolean onContextItemSelected(MenuItem item){    
            if(item.getTitle()=="Call"){  
                Toast.makeText(getApplicationContext(),"calling code",Toast.LENGTH_LONG).show();  
            }    
            else if(item.getTitle()=="SMS"){  
                Toast.makeText(getApplicationContext(),"sending sms code",Toast.LENGTH_LONG).show();  
            }else{  
               return false;  
            }    
          return true;    
      }    
    }

Answer 1

使用 .equals代替== 来比较字符串：

改变这个：

if(item.getTitle()=="Call"){  
                Toast.makeText(getApplicationContext(),"calling code",Toast.LENGTH_LONG).show();  
            }    
            else if(item.getTitle()=="SMS"){  
                Toast.makeText(getApplicationContext(),"sending sms code",Toast.LENGTH_LONG).show();  
            }

到此：

if(item.getTitle().equals("Call"){  
                Toast.makeText(getApplicationContext(),"calling code",Toast.LENGTH_LONG).show();  
            }    
            else if(item.getTitle().equals("SMS"){  
                Toast.makeText(getApplicationContext(),"sending sms code",Toast.LENGTH_LONG).show();  
            }

有关详细信息，请参阅this

在android中实现上下文菜单的问题

1 个答案: