创建弹出菜单

1.ActionBar中的菜单：http://www.tuicool.com/articles/VrUBRf

2.ContextMenu(上下文菜单)

• 首先在res/menu/中创建一个XML文件，以定义菜单，我们将其命名为options

  <?xml version="1.0" encoding="utf-8"?>
  <menu xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:tools="http://schemas.android.com/tools">
  
      <item
          android:id="@+id/add_item"
          android:title="Add Item"
          android:icon="@drawable/ic_launcher"
          android:showAsAction="ifRoom"
          tools:ignore="AppCompatResource"
          />
      <item
          android:id="@+id/remove_item"
          android:title="remove Item"
          android:icon="@drawable/ic_launcher"
          android:showAsAction="always"
          tools:ignore="AppCompatResource"
          />
      <item
          android:id="@+id/menu_edit"
          android:title="edit Item"
          android:icon="@drawable/ic_launcher"
          android:showAsAction="never"
          tools:ignore="AppCompatResource"
          />
  </menu>

• 然后再Activity中用onCreatContextMenu()和onContextItemSelected()方法填充菜单，处理用户的选择

• @Override
      public boolean onContextItemSelected(MenuItem item) {
          switch(item.getItemId()){
              case R.id.add_item:
                  //执行添加动作
                  break;
              case R.id.remove_item:
                  //执行删除动作
                  break;
              case R.id.menu_edit:
                  break;
              default:
                  return super.onContextItemSelected(item);
          }
          return true;
      }
  
  
      @Override
      public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
          menu.setHeaderTitle("Choose an option");
          getMenuInflater().inflate(R.menu.options,menu);
          super.onCreateContextMenu(menu, v, menuInfo);
  
      }

• 默认是用户长按item时会触发菜单项，进而弹出选项框
• 使用时要使用registerForContextMenu(View view)来注册菜单，即将ContextMenu绑定到某个view中
• 示例：

  package com.example.qjm3662.service_learn;
  
  import android.content.ComponentName;
  import android.content.Intent;
  import android.content.ServiceConnection;
  import android.os.IBinder;
  import android.support.v7.app.AppCompatActivity;
  import android.os.Bundle;
  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.TimePicker;
  import android.widget.Toast;
  
  public class MainActivity extends AppCompatActivity {
  
      private static final String[] ITEMS = {"Lost","Time","Will","Never","Be","Find","again!"};
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          ListView list = new ListView(this);
          ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,ITEMS);
          list.setAdapter(adapter);
          registerForContextMenu(list);
          setContentView(list);
      }
  
  
  
  
      @Override
      public boolean onContextItemSelected(MenuItem item) {
          switch(item.getItemId()){
              case R.id.add_item:
                  //执行添加动作
                  break;
              case R.id.remove_item:
                  //执行删除动作
                  break;
              case R.id.menu_edit:
                  break;
              default:
                  return super.onContextItemSelected(item);
          }
          return true;
      }
  
  
      @Override
      public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
          menu.setHeaderTitle("Choose an option");
          getMenuInflater().inflate(R.menu.options,menu);
          super.onCreateContextMenu(menu, v, menuInfo);
  
      }
  
  
     
  }

  

3.ActionMode

　　激活ActionMode后会在系统的ActionBar上出现一个自定义的菜单，覆盖在原ActionBar上，并出现一个额外的可以退出ActionMode的选项。还允许同时选择多个条目来执行同一个动作。

package com.example.qjm3662.service_learn;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.ActionMode;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AbsListView;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;

public class MainActivity extends AppCompatActivity implements AbsListView.MultiChoiceModeListener{

    ListView list;
    private static final String[] ITEMS = {"Lost","Time","Will","Never","Be","Find","again!"};
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        list = new ListView(this);
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,ITEMS);
        list.setAdapter(adapter);
        list.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE_MODAL);
        list.setMultiChoiceModeListener(this);
        setContentView(list);
    }


    @Override
    //当子控件的选择状态发生改变时调用该方法
    public void onItemCheckedStateChanged(ActionMode mode, int position, long id, boolean checked) {
        //获得list中被选中的item数目
        int count = list.getCheckedItemCount();
        mode.setTitle(String.format("%d Selected", count));
    }

    @Override
    public boolean onCreateActionMode(ActionMode mode, Menu menu) {
        getMenuInflater().inflate(R.menu.options,menu);
        return true;
    }

    @Override
    public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
        //如果ActionMode一直是无效，可以在这里做些工作来更新菜单
        return true;
    }

    @Override
    public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
        //通过条目的Id得到用户的选择动作
        switch (item.getItemId()){
            case R.id.add_item:
                //执行添加动作
                break;
            case R.id.remove_item:
                //执行删除动作
                break;
            case R.id.menu_edit:
                break;
            default:
                return false;
        }
        return true;
    }

    @Override
    public void onDestroyActionMode(ActionMode mode) {
        //退出ActionMode时会调用该方法
    }
}