ContextMenu上下文菜单

1.ContextMenu菜单的组成部分

• 标题及标题图标
• 菜单内容
• 菜单内容的点击响应事件

2.ContextMenu与OptionMenu的区别

• OptionMenu对应的是activity，一个activity只能拥有一个选项菜单
• ContextMenu对应的是View，每个View都可以设置上下文菜单

3.ContextMenu的创建方法

• 首先给View注册上下文菜单registerForContextMenu()
• 添加上下文菜单内容onCreateContextMenu()
• 设置菜单点击后响应事件onContextItemSelected()

实例一：动态添加

package com.example.demo16;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.ContextMenu;import android.view.MenuItem;import android.view.View;import android.widget.ArrayAdapter;import android.widget.ListView;import android.widget.Toast;import java.util.ArrayList;public class MainActivity extends AppCompatActivity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        showListView();    }    /**     * 设置ListView显示内容     */    private void showListView(){        ListView listView = (ListView) findViewById(R.id.listView);        ArrayAdapter
    
      adapter = new ArrayAdapter
     
      (this,                                            android.R.layout.simple_list_item_1, getData());        listView.setAdapter(adapter);        this.registerForContextMenu(listView);    }    @Override    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {        super.onCreateContextMenu(menu, v, menuInfo);        //设置Menu显示内容        menu.setHeaderTitle("文件操作");        menu.setHeaderIcon(R.drawable.file);        menu.add(1, 100, 1, "复制");        menu.add(1, 101, 1, "剪切");        menu.add(1, 102, 1, "粘贴");    }    @Override    public boolean onContextItemSelected(MenuItem item) {        switch (item.getItemId()) {            case 100:                Toast.makeText(MainActivity.this, "点击了复制", Toast.LENGTH_SHORT).show();                break;            case 101:                Toast.makeText(MainActivity.this, "点击了剪切", Toast.LENGTH_SHORT).show();                break;            case 102:                Toast.makeText(MainActivity.this, "点击了粘贴", Toast.LENGTH_SHORT).show();                break;        }        return super.onContextItemSelected(item);    }    /**     * 构造ListView显示的数据     * @return     */    private ArrayList
      
        getData(){        ArrayList
       
         list = new ArrayList
        
         ();        for(int i=0; i<5; ++i) {            list.add("文件" + i);        }        return list;    }}
        
       
      
     
    

运行效果：

实例二：使用xml添加

1.在资源目录res下创建menu资源文件夹

2.在menu文件夹下创建main.xml文件

3.创建菜单

package com.example.demo16;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;import java.util.ArrayList;public class MainActivity extends AppCompatActivity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        showListView();    }    /**     * 设置ListView显示内容     */    private void showListView(){        ListView listView = (ListView) findViewById(R.id.listView);        ArrayAdapter
    
      adapter = new ArrayAdapter
     
      (this,                                            android.R.layout.simple_list_item_1, getData());        listView.setAdapter(adapter);        //注册上下文菜单        this.registerForContextMenu(listView);    }    @Override    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {        super.onCreateContextMenu(menu, v, menuInfo);        //设置Menu显示内容        menu.setHeaderTitle("文件操作");        menu.setHeaderIcon(R.drawable.file);        MenuInflater inflater = getMenuInflater();        inflater.inflate(R.menu.main, menu);    }    @Override    public boolean onContextItemSelected(MenuItem item) {        switch (item.getItemId()) {            case R.id.action_item1:                Toast.makeText(MainActivity.this, "点击了复制", Toast.LENGTH_SHORT).show();                break;            case R.id.action_item2:                Toast.makeText(MainActivity.this, "点击了剪切", Toast.LENGTH_SHORT).show();                break;            case R.id.action_item3:                Toast.makeText(MainActivity.this, "点击了粘贴", Toast.LENGTH_SHORT).show();                break;        }        return super.onContextItemSelected(item);    }    /**     * 构造ListView显示的数据     * @return     */    private ArrayList
      
        getData(){        ArrayList
       
         list = new ArrayList
        
         ();        for(int i=0; i<5; ++i) {            list.add("文件" + i);        }        return list;    }}
        
       
      
     
    

效果如上例