spinner实现下拉列表

package com.example.spinner;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.SimpleAdapter;
import android.widget.Spinner;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import butterknife.Bind;
import butterknife.ButterKnife;

public class MainActivity extends AppCompatActivity implements AdapterView.OnItemSelectedListener {

    @Bind(R.id.tv)
    TextView tv;
    @Bind(R.id.spinner)
    Spinner spinner;
    @Bind(R.id.spinner2)
    Spinner spinner2;

    private List<String> list;
    private ArrayAdapter<String> stringArrayAdapter;
    private List<Map<String, Object>> mData;
    private SimpleAdapter simpleAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.bind(this);
        list = new ArrayList<>();
        list.add("北京");
        list.add("济南");
        list.add("苏州");
        list.add("菏泽");
        tv.setText("您选择的城市是北京");
        initSpinner1();
        mData=new ArrayList<>();
        initData();
        simpleAdapter = new SimpleAdapter(this, mData, R.layout.item_spinner2, new String[]{"image", "text"}, new int[]{R.id.iv_item, R.id.tv_item});

        simpleAdapter.setDropDownViewResource(R.layout.item_spinner2);
        spinner2.setAdapter(simpleAdapter);
        spinner2.setOnItemSelectedListener(this);
    }

    private void initData() {
        for (int i = 0; i < list.size(); i++) {
            HashMap<String, Object> objectObjectHashMap = new HashMap<>();
            objectObjectHashMap.put("image",R.mipmap.ic_launcher);
            objectObjectHashMap.put("text",list.get(i));
            mData.add(objectObjectHashMap);
        }

    }

    private void initSpinner1() {
        // 新建ArrayAdapter 数组适配器
        stringArrayAdapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_item, list);
        // adapter设置一个下拉列表样式
        stringArrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner.setAdapter(stringArrayAdapter);
//        spinner.setOnItemClickListener(this);
        spinner.setOnItemSelectedListener(this);
    }


    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
        switch (parent.getId()) {
            case R.id.spinner:
                String cityName = stringArrayAdapter.getItem(position);
                tv.setText("您选择的城市是" + cityName);
                break;
            case R.id.spinner2:
                Map<String, Object> stringObjectMap = mData.get(position);

                String text = (String) stringObjectMap.get("text");

                tv.setText("您选择的城市是" + text);
                break;
        }

    }

    @Override
    public void onNothingSelected(AdapterView<?> parent) {

    }
}

//布局代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
android:orientation="vertical"
    tools:context="com.example.spinner.MainActivity">

    <TextView
        android:id="@+id/tv"
        android:textSize="25sp"
        android:textColor="@android:color/holo_red_light"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
     />
    <Spinner
        android:id="@+id/spinner"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"></Spinner>
    <Spinner
        android:id="@+id/spinner2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"></Spinner>
</LinearLayout>

//条目布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal" android:layout_width="match_parent"
    android:layout_height="match_parent">
<ImageView
    android:id="@+id/iv_item"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />
    <TextView
    android:id="@+id/tv_item"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />
</LinearLayout>