Spinner控件:Spinner绑定的监听是SetOnItemSelectedListener

（一）

1.效果图：ArrayAdapter可以不用设置

arrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_item);

2.activity_main.xml

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     xmlns:tools="http://schemas.android.com/tools"
 4     android:layout_width="match_parent"
 5     android:layout_height="match_parent"
 6     android:orientation="vertical"
 7     tools:context="com.example.app3.MainActivity">
 8 
 9     <Spinner
10         android:id="@+id/spin"
11         android:background="@color/colorAccent"
12         android:layout_width="match_parent"
13         android:layout_height="wrap_content"
14         android:dropDownVerticalOffset="100dp"
15         android:dropDownHorizontalOffset="100dp"
16         />
17 </LinearLayout>

3.MianActivity.java

 1 package com.example.app3;
 2 
 3 import android.support.v7.app.AppCompatActivity;
 4 import android.os.Bundle;
 5 import android.view.View;
 6 import android.widget.Adapter;
 7 import android.widget.AdapterView;
 8 import android.widget.ArrayAdapter;
 9 import android.widget.Spinner;
10 import android.widget.Toast;
11 
12 import java.util.ArrayList;
13 import java.util.List;
14 
15 public class MainActivity extends AppCompatActivity {
16     private Spinner spinner;
17     private List<String> list;
18     private ArrayAdapter arrayAdapter;
19 
20 
21     @Override
22     protected void onCreate(Bundle savedInstanceState) {
23         super.onCreate(savedInstanceState);
24         setContentView(R.layout.activity_main);
25 
26         spinner=(Spinner)findViewById(R.id.spin);
27 
28         //新建适配器
29         list = new ArrayList<>();
30         for (int i=0;i<3;i++){
31             list.add("spinner"+i);
32         }
33         arrayAdapter = new ArrayAdapter(MainActivity.this,android.R.layout.simple_spinner_item,list);
34 
35         spinner.setAdapter(arrayAdapter);
36 
37         spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
38             @Override
39             public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
40                 Toast.makeText(MainActivity.this,list.get(position),Toast.LENGTH_SHORT).show();
41             }
42 
43             @Override
44             public void onNothingSelected(AdapterView<?> parent) {
45 
46             }
47         });
48     }
49 }

（二）用简单适配器的时候必须设置