Android下拉列表（Spinner）效果（使用C#和Java分别实现）

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);    }  }}

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) {      }    });  }}

<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>