5使用Spinner实现下拉列表

5-1 步骤

 

 

5-2 实现下拉列表

MainActivity.java

package com.example.andriod2_spinner;

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

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.TextView;

public class MainActivity extends Activity implements OnItemSelectedListener
{
    private TextView textView;
    private Spinner spinner;
    private List<String> list;
    private ArrayAdapter<String>adapter;
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textView=(TextView)findViewById(R.id.text);
        textView.setText("您选择的是");
        spinner=(Spinner)findViewById(R.id.spinner);
        
//        1.设计数据源
    list=new ArrayList<String>();
    list.add("上海");
    list.add("广州");
    list.add("深圳");
    list.add("北京");
//    2.新建ArrayaAdapter(数组适配器)
    adapter=new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item,list);
//    3.adapter设置一个下拉列表样式
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
//    4.spinner加载适配器
    spinner.setAdapter(adapter);
//    5.spinner设置监听器
    spinner.setOnItemSelectedListener(this);
    }
    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position,
            long id)
    {
        // TODO Auto-generated method stub
        String cityName=adapter.getItem(position);
        //String cityName1=list.get(position);
        textView.setText("您选择的是"+cityName);
    }
    @Override
    public void onNothingSelected(AdapterView<?> parent)
    {
        // TODO Auto-generated method stub
        
    }

}

Activity_mian.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textColor="#ff0000"
        android:textSize="25sp" />

    <Spinner
        android:id="@+id/spinner"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" />

</LinearLayout>

       

5-3 利用SimpleAdapter实现自定义样式Spinner

MainActivity.java

package com.example.spinner;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import android.app.Activity;
import android.app.ActionBar;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.Animation;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.SimpleAdapter;
import android.widget.Spinner;
import android.widget.TextView;
import android.os.Build;

public class MainActivity extends Activity {

    private TextView myTextView;
    private Spinner mySpinner;
    private SimpleAdapter adapter;
    private List<Map<String, Object>> dataList;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        // 第一步：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
        dataList = new ArrayList<Map<String, Object>>();
        getData();
        myTextView = (TextView) findViewById(R.id.textView);
        mySpinner = (Spinner) findViewById(R.id.spinner);
        // 第二步：为下拉列表定义一个适配器，这里就用到里前面定义的list。
        adapter=new SimpleAdapter(this, dataList, R.layout.item, new String[]{"image","text"}, new int[]{R.id.image,R.id.text});
        
        // 第三步：为适配器设置下拉列表下拉时的菜单样式。
        adapter.setDropDownViewResource(R.layout.item);
        // 第四步：将适配器添加到下拉列表上
        mySpinner.setAdapter(adapter);
        // 第五步：为下拉列表设置各种事件的响应，这个事响应菜单被选中

        mySpinner
                .setOnItemSelectedListener(new Spinner.OnItemSelectedListener() {
                    public void onItemSelected(AdapterView<?> arg0, View arg1,
                            int arg2, long arg3) {
                        // TODO Auto-generated method stub
                        /* 将所选mySpinner 的值带入myTextView 中 */
                        myTextView.setText("您选择的是：" + adapter.getItem(arg2));
                    }

                    public void onNothingSelected(AdapterView<?> arg0) {
                        // TODO Auto-generated method stub
                        myTextView.setText("NONE");
                    }
                });

    }

    private void getData() {
        // TODO Auto-generated method stub
        Map<String, Object> map = new HashMap<String, Object>();
        map.put("image", R.drawable.ic_launcher);
        map.put("text", "北京");
        Map<String, Object> map2 = new HashMap<String, Object>();
        map2.put("image", R.drawable.ic_launcher);
        map2.put("text", "上海");
        Map<String, Object> map3 = new HashMap<String, Object>();
        map3.put("image", R.drawable.ic_launcher);
        map3.put("text", "广州");
        Map<String, Object> map4 = new HashMap<String, Object>();
        map4.put("image", R.drawable.ic_launcher);
        map4.put("text", "深圳");
        dataList.add(map);
        dataList.add(map2);
        dataList.add(map3);
        dataList.add(map4);
    }

}

Item.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <ImageView
        android:id="@+id/image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_centerVertical="true"
        android:layout_marginLeft="10dp"
        android:src="@drawable/ic_launcher" />

    <TextView
        android:id="@+id/text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        android:layout_marginLeft="20dp"
        android:layout_toRightOf="@id/image"
        android:text="None" />

</RelativeLayout>

Main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/textView"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="你选择的是"
        android:textSize="25sp" 
        android:textColor="#ff0000"
        >
    </TextView>

    <Spinner
        android:id="@+id/spinner"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" >
    </Spinner>
    <!-- 定义一个下拉菜单 -->

</LinearLayout>