Spinner显示下拉列表

Main代码
 1 package spinnerdemo.example.administrator.spinnerdemo;

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

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends Activity implements AdapterView.OnItemSelectedListener{
    private Spinner spinner;
    private TextView textView;
    private List<String> list;
    private ArrayAdapter<String> arrayAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        /*使用Spinner的步骤:
        1.添加一个下拉列表项的list,这里添加的项就是下拉列表的菜单项:
        private List<String> list=new ArrayList<String>();
        list.add("上海");
        2.为下拉列表定义一个数组适配器(ArrayAdapter),这里使用到前面的LIst
        adapter=new ArrayAdapter<String>(this,android.R.layout.simpe_spinner_item,list);
        3.为适配器设置下拉列表下拉时候的菜单样式:
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        4.将适配器添加到下拉列表中
        mySpinner.setAdapter(adapter)
        5.为下拉列表设置各种事件的响应,这个事件响应菜单被选中;
        mySpinner.setOnItemSelectedListener(new Spinner.OnIteSelectedListener())*/
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        spinner= (Spinner) findViewById(R.id.spinner);
        textView= (TextView) findViewById(R.id.text);
        textView.setText("您选择的城市为北京");
        /*添加下拉列表的list，添加的是下拉列表的菜单项*/
        list=new ArrayList<String>();
        list.add("北京");
        list.add("天津");
        list.add("上海");
        list.add("广州");
       /* 为下拉列表定义数组适配器*/
        arrayAdapter=new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item,list);
        /*为数组适配器设置下拉列表下拉时候的菜单样式*/
        arrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        /*将适配器添加到下拉列表中*/
        spinner.setAdapter(arrayAdapter);
        spinner.setOnItemSelectedListener(this);
    }

    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
//       String cityName=arrayAdapter.getItem(position);
        String cityName=list.get(position);
        textView.setText("您选择的城市"+cityName);

    }

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

    }
}

 

main.xml代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/text"
        android:textColor="#ff0000"
        android:textSize="25sp"
       />
    <Spinner
        android:layout_marginTop="10dp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/spinner"
        ></Spinner>
</LinearLayout>