Android学习-使用Spinner实现下拉列表

注：也可以通过SimpleAdapter的方法来自定义Spinner的样式，例如有图片有文字。

package com.example.angel.listviewpro;
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.Spinner;
import android.widget.TextView;

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

public class MainAcitivity extends AppCompatActivity implements AdapterView.OnItemSelectedListener {

    private TextView textView;
    private Spinner spinner;
    private List<String> list;
    private ArrayAdapter<String>adapter;
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main_layout);

        textView = (TextView) findViewById(R.id.textView);
        spinner = (Spinner)findViewById(R.id.spinner);
        textView.setText("您选择的城市是北京");
        //1.数据源
        list = new ArrayList<>();
        list.add("北京");
        list.add("上海");
        list.add("广州");
        list.add("深圳");
        //2.新建ArrayAdapter(只是文字，所以选择这个适配器)
        adapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,list);
        //3.设置下拉列表样式
        //setDropDownViewResource(int resource)
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        //4.加载适配器
        spinner.setAdapter(adapter);
        //5.spinner设置监听器
        spinner.setOnItemSelectedListener(this);
    }
    public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
        String cityName = adapter.getItem(i);
        //list.get(i);与上一行相同
        textView.setText("您选择的是"+cityName);
    }

    public void onNothingSelected(AdapterView<?> adapterView) {

    }
}

<?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:id="@+id/textView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="25sp"
        android:textColor="#ff0000"/>
    <Spinner
        android:id="@+id/spinner"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>


</LinearLayout>