Android下拉列表（Spinner）效果（使用C#和Java分别实现）

效果如下：

c#实现代码

using android.app;
using android.os;
using android.widget;

namespace spinnerdemo
{
  [activity(label = "@string/applicationname", mainlauncher = true, icon = "@drawable/icon")]
  public class mainactivity : activity
  {
    private spinner _cityspinner;
    private textview _citynameview;
    private arrayadapter<string> _cityinfos;

   
    protected override void oncreate(bundle bundle)
    {
      base.oncreate(bundle);

      setcontentview(resource.layout.main);
      _cityspinner = findviewbyid<spinner>(resource.id.sp_city);
      _citynameview = findviewbyid<textview>(resource.id.txt_cityname);

      _cityinfos = new arrayadapter<string>(this, android.resource.layout.simplespinnerdropdownitem);
      _cityinfos.add("成都");
      _cityinfos.add("兰州");
      _cityinfos.add("武汉");
      _cityinfos.add("上海");
      _cityspinner.adapter = _cityinfos;
      _cityspinner.itemselected += cityselectedevent;
    }

    private void cityselectedevent(object sender, adapterview.itemselectedeventargs e)
    {
      _citynameview.text = _cityinfos.getitem(e.position);
    }
  }
}

java实现代码

package com.example.halower.spinnerdemo;

import android.os.bundle;
import android.support.v7.app.actionbaractivity;
import android.view.view;
import android.widget.adapterview;
import android.widget.arrayadapter;
import android.widget.spinner;
import android.widget.textview;
public class mainactivity extends actionbaractivity {
  private spinner _cityspinner;
  private textview _citynameview;
  private arrayadapter<string> _cityinfo;
  @override
  protected void oncreate(bundle savedinstancestate) {
    super.oncreate(savedinstancestate);
    setcontentview(r.layout.activity_main);
    _cityspinner =(spinner)findviewbyid(r.id.sp_city);
    _citynameview =(textview) findviewbyid(r.id.txt_cityname);

    _cityinfo =new arrayadapter<>(this,r.layout.support_simple_spinner_dropdown_item);
    _cityinfo.add("成都");
    _cityinfo.add("兰州");
    _cityinfo.add("武汉");
    _cityinfo.add("上海");
    _cityspinner.setadapter(_cityinfo);
    _cityspinner.setonitemselectedlistener(new adapterview.onitemselectedlistener() {
      @override
      public void onitemselected(adapterview<?> parent, view view, int position, long id) {
        _citynameview.settext(_cityinfo.getitem(position));
      }

      @override
      public void onnothingselected(adapterview<?> parent) {

      }
    });
  }
}

layout

<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:paddingleft="@dimen/activity_horizontal_margin"
  android:paddingright="@dimen/activity_horizontal_margin"
  android:paddingtop="@dimen/activity_vertical_margin"
  android:paddingbottom="@dimen/activity_vertical_margin" tools:context=".mainactivity">

  <spinner
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/sp_city"
    android:layout_alignparenttop="true"
    android:layout_alignparentright="true"
    android:layout_alignparentend="true"
    android:layout_toendof="@+id/txt_cityname"
    android:layout_torightof="@+id/txt_cityname" />
  <textview
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="城市"
    android:id="@+id/txt_cityname"
    android:layout_alignparentleft="true"
    android:layout_alignparentstart="true" />
</relativelayout>