如何在Android应用中利用Spinner实现一个下拉列表功能

//(layout)activity_main
<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.test.spinner.MainActivity">
 <LinearLayout
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:orientation="horizontal">
  <TextView
   android:textSize="20sp"
   android:layout_margin="10dp"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:text="今年的常规赛MVP："/>
  <TextView
   android:id="@+id/text"
   android:textSize="20sp"
   android:layout_marginTop="10dp"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"/>
 </LinearLayout>
 <Spinner
  android:visibility="gone"
  android:id="@+id/spinner"
  android:layout_marginLeft="10dp"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content">
 </Spinner>
</LinearLayout>
-------------------------------------------------------------------
//(layout)item
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:gravity="center_vertical">
 <ImageView
  android:id="@+id/imageView"
  android:layout_width="80dp"
  android:layout_height="80dp"/>
 <TextView
  android:id="@+id/textView"
  android:layout_marginLeft="20dp"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"/>
</LinearLayout>

//MainActivity
import android.content.Context;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;
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 static com.test.spinner.R.id.simpleAdapter;
public class MainActivity extends AppCompatActivity {
 private Context mContext = MainActivity.this;
 private Spinner mSpinner;
 private ArrayAdapter<String> mArrayAdapter;
 private TextView mTextView;
 private SimpleAdapter mSimpleAdapter;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  initView();
  initData();
 }
 private void initView(){
  mSpinner = (Spinner) findViewById(R.id.spinner);
  mTextView = (TextView) findViewById(R.id.text);
 }
 private void initData(){
  // 设置数据集
  List<String> list = new ArrayList<>();
  list.add("哈登");
  list.add("莱昂纳德");
  list.add("詹姆斯");
  list.add("威斯布鲁克");
  List<Map<String ,Object>> maps = new ArrayList<>();
  int[] icon = {R.mipmap.pic1 , R.mipmap.pic2, R.mipmap.pic3, R.mipmap.pic4};
  String[] iconName = {"哈登" , "莱昂纳德" , "詹姆斯" , "威斯布鲁克"};
  // 设置适配器
  mArrayAdapter = new ArrayAdapter<>(mContext ,
    android.R.layout.simple_spinner_item , list);
  mArrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
  mSimpleAdapter = new SimpleAdapter(mContext,
    maps , R.layout.item , new String[]{"image" , "text"} , new int[]{R.id.imageView ,R.id.textView});
  for(int i = 0 ; i < icon.length ; i++){
   Map<String ,Object> map = new HashMap<>();
   map.put("image", icon[i]);
   map.put("text" , iconName[i]);
   maps.add(map);
  }
 }
 @Override
 public boolean onCreateOptionsMenu(Menu menu) {
  getMenuInflater().inflate(R.menu.main , menu);
  return true;
 }
 @Override
 public boolean onOptionsItemSelected(MenuItem item) {
  switch (item.getItemId()){
   case R.id.arrayAdapter:
    mSpinner.setVisibility(View.VISIBLE);
    mSpinner.setAdapter(mArrayAdapter);
    // 设置监听器
    mSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
     @Override
     public void onItemSelected(AdapterView<&#63;> adapterView, View view, int position, long id) {
      mTextView.setText(mArrayAdapter.getItem(position));
     }
     @Override
     public void onNothingSelected(AdapterView<&#63;> adapterView) {
     }
    });
    break;
   case simpleAdapter:
    mSpinner.setVisibility(View.VISIBLE);
    mSpinner.setAdapter(mSimpleAdapter);
    // 设置监听器
    mSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
     @Override
     public void onItemSelected(AdapterView<&#63;> adapterView, View view, int position, long id) {
      mTextView.setText(mSimpleAdapter.getItem(position)+"");
     }
     @Override
     public void onNothingSelected(AdapterView<&#63;> adapterView) {
     }
    });
    break;
   default:
    break;
  }
  return super.onOptionsItemSelected(item);
 }
}