Android上下文菜单示例

当用户长按元素时，Android上下文菜单会出现。这也被称为浮动菜单。

在对选定内容执行操作时，它会影响选定的内容。

它不支持项快捷方式和图标。

Android上下文菜单示例

让我们看一下Android上下文菜单的简单示例。

activity_main.xml

从面板中拖动一个ListView，现在xml文件将如下所示：

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>  
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"  
    xmlns:app="http://schemas.android.com/apk/res-auto"  
    xmlns:tools="http://schemas.android.com/tools"  
    android:layout_width="match_parent"  
    android:layout_height="match_parent"  
    tools:context="example.javatpoint.com.contextmenu.MainActivity">  

    <ListView  
        android:layout_width="368dp"  
        android:layout_height="495dp"  
        android:id="@+id/listView"  
        android:layout_marginEnd="8dp"  
        android:layout_marginStart="8dp"  
        android:layout_marginTop="8dp"  
        app:layout_constraintEnd_toEndOf="parent"  
        app:layout_constraintHorizontal_bias="0.0"  
        app:layout_constraintStart_toStartOf="parent"  
        app:layout_constraintTop_toTopOf="parent" />  
</android.support.constraint.ConstraintLayout>

main_menu.xml

在菜单目录中创建一个单独的menu_main.xml文件，用于存储菜单项。

<?xml version="1.0" encoding="utf-8"?>  
<menu xmlns:android="http://schemas.android.com/apk/res/android">  
    <item android:id="@+id/call"  
        android:title="Call" />  
    <item android:id="@+id/sms"  
        android:title="SMS" />  
</menu>

Activity类

让我们编写代码，在按下列表视图时显示上下文菜单。

package example.javatpoint.com.contextmenu;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    ListView listView;
    String contacts[]={"Ajay","Sachin","Sumit","Tarun","Yogesh"};
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        listView=(ListView)findViewById(R.id.listView);
        ArrayAdapter adapter=new ArrayAdapter(this,android.R.layout.simple_list_item_1,contacts);
        listView.setAdapter(adapter);
        // Register the ListView  for Context menu
        registerForContextMenu(listView);
    }
    @Override
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo)
    {
        super.onCreateContextMenu(menu, v, menuInfo);
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.menu_main, menu);
        menu.setHeaderTitle("Select The Action");
    }
    @Override
    public boolean onContextItemSelected(MenuItem item){
        if(item.getItemId()==R.id.call){
            Toast.makeText(getApplicationContext(),"calling code",Toast.LENGTH_LONG).show();
        }
        else if(item.getItemId()==R.id.sms){
            Toast.makeText(getApplicationContext(),"sending sms code",Toast.LENGTH_LONG).show();
        }else{
            return false;
        }
        return true;
    }
}