Android中的ContextMenu

Android 的ContextMenu,即上下文菜单。(类似电脑上的鼠标右键功能,选中某个元素,然后点右键,在弹出菜单上执行操作。)在手机上,通过长时间按住界面上的元素,就会出现事先设计好的上下文菜单。

实现ContextMenu,一般要用到以下三个方法:

(1)registerForContextMenu(getExpandableListView());//注册上下文菜单

(2)onCreateContextMenu(ContextMenu menu, View v,ContextMenuInfo menuInfo);//创建上下文菜单

(3)onContextItemSelected(MenuItem item);//上下文菜单的选中事件

Tips:Options Menu的拥有者是Activity,而上下文菜单的拥有者是Activity中的View。每个Activity有且只有一个Options Menu,它为整个Activity服务。而一个Activity往往有多个View,并不是每个View都有上下文菜单,这就需要我们调用registerForContextMenu(View view)来指定。

上代码:

import android.app.Activity;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.ContextMenu;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.Window;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;
import java.util.ArrayList;


public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.activity_main);
        showListView();
    }

    private void showListView(){
        ListView listView = (ListView) findViewById(R.id.lv);
        ArrayAdapter<String> adapter=new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,getData());
        listView.setAdapter(adapter);
        this.registerForContextMenu(listView);//注册上下文菜单
    }

    //创建菜单      
    @Override
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
        super.onCreateContextMenu(menu, v, menuInfo);
        //设置mune显示的内容
        menu.setHeaderTitle("文件操作");
        menu.setHeaderIcon(R.drawable.ic_launcher);
//         public MenuItem add(int groupId, int itemId, int order, CharSequence title);
        menu.add(1,1,1,"copy");
        menu.add(1,2,1,"cut");
        menu.add(1,3,1,"past");
        menu.add(1,4,1,"cancel");
    }
    //响应菜单
    @Override
    public boolean onContextItemSelected(MenuItem item) {
        switch (item.getItemId()){
            case 1:
                Toast.makeText(this, "clicked copy",Toast.LENGTH_SHORT).show();
                break;
            case 2:
                Toast.makeText(this, "clicked cut",Toast.LENGTH_SHORT).show();
                break;
            case 3:
                Toast.makeText(this, "clicked past",Toast.LENGTH_SHORT).show();
                break;
            case 4:
                Toast.makeText(this, "clicked cancel",Toast.LENGTH_SHORT).show();
                break;
        }
        return super.onContextItemSelected(item);
    }

    private ArrayList<String> getData(){
        ArrayList<String> list=new ArrayList<>();
        for(int i=0;i<5;i++){
            list.add("file"+(i+1));
        }
        return list;
    }
}

效果:

参考:

  1. Android 菜单(ContextMenu)
  2. Android之ContextMenu的使用方法以及与OptionMenu的区别

感谢原作者。

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