安卓——Spinner(下拉列表)

activity_main.xml

MainActivity.java

package com.example.lenovo.spinner;

import android.app.Activity;
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 TextView textView;
    private Spinner spinner;
    private List data;
    private ArrayAdapter adapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textView=(TextView) findViewById(R.id.textView);
        spinner=(Spinner)findViewById(R.id.spinner);
        data=new ArrayList();
        textView.setText("您选择的城市是北京");
        //1、添加数据源，就是下拉菜单选项
        data.add("北京");
        data.add("深圳");
        data.add("上海");
        data.add("广州");
        //2、未下来列表定义一个数组适配器
        adapter=new ArrayAdapter(this,android.R.layout.simple_list_item_1,data);
        //3、为适配器设置下拉菜单的样式
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        //4、将适配器配置到下拉列表上
        spinner.setAdapter(adapter);
        //5、给下拉菜单设置监听事件
        spinner.setOnItemSelectedListener(this);
    }



    @Override
    public void onItemSelected(AdapterView adapterView, View view, int i, long l) {
        String cityName=data.get(i);
        textView.setText("您选择的城市是"+cityName);
    }

    @Override
    public void onNothingSelected(AdapterView adapterView) {

    }
}

Item.xml

activity_main.xml

MainActivity.java

package com.example.lenovo.simpleadpaterofspinner;

import android.app.Activity;
import android.os.Bundle;
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;

public class MainActivity extends Activity {

    private TextView textView;
    private Spinner spinner;
    private List>data;
    private SimpleAdapter adapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textView=(TextView)findViewById(R.id.text);
        spinner=(Spinner)findViewById(R.id.spinneer);
        //1.添加一个下拉列表的数据源
        data= new ArrayList>();
        getdata();
        //2.为下拉列表定义一个适配器
        adapter=new SimpleAdapter(this,data,R.layout.item,new String[]{"image","text"},new int[]{R.id.image,R.id.textview});
        //3.为适配器设置下拉列表的样式
        adapter.setDropDownViewResource(R.layout.item);
        //4.给下拉列表添加适配器
        spinner.setAdapter(adapter);
        //5.为下来列表设置各种响应事件
        spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView adapterView, View view, int i, long l) {
                textView.setText("您选择的是:"+adapter.getItem(i));
            }

            @Override
            public void onNothingSelected(AdapterView adapterView) {
                textView.setText("None");
            }
        });

    }

    private void getdata(){
        Mapmap1=new HashMap();
        map1.put("imag",R.mipmap.ic_launcher);
        map1.put("text","北京");
        Mapmap2=new HashMap();
        map2.put("imag",R.mipmap.ic_launcher);
        map2.put("text","上海");
        Mapmap3=new HashMap();
        map3.put("imag",R.mipmap.ic_launcher);
        map3.put("text","深圳");
        Mapmap4=new HashMap();
        map4.put("imag",R.mipmap.ic_launcher);
        map4.put("text","广州");
        data.add(map1);
        data.add(map2);
        data.add(map3);
        data.add(map4);
    }
}