下拉列表

package com.dream.myapplication;

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 AppCompatActivity implements AdapterView.OnItemSelectedListener {
    private ArrayAdapter<String> adapter;
    private TextView textView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        //加载开始场景
        super.onCreate(savedInstanceState);
        //加载布局
        setContentView(R.layout.activity_main);
        //设置显示窗口
         textView = (TextView)findViewById(R.id.text_view);
        //下拉列表控件
        Spinner spinner = (Spinner)findViewById(R.id.a_spiner);
        //数据源
        List<String> list = new ArrayList<String>();
        list.add("华山");
        list.add("丽江");
        list.add("西藏");
        list.add("青岛");
        //数组适配器
        adapter = new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item,list);
        //下拉列表设置样式
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        //加载适配器
        spinner.setAdapter(adapter);
        //spiner设置监听器
        spinner.setOnItemSelectedListener(this);
    }
    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
        String cityName = adapter.getItem(position);
        textView.setText("你将要去"+cityName);
    }
    @Override
    public void onNothingSelected(AdapterView<?> parent) {

    }
}