android入门——UI(3)

Spinner控件 ListView控件

一、Spinner控件

点击Spinner会弹出一个包含所有可选值的dropdown菜单，从该菜单中可以为Spinner选择一个新值。

有两种指定数据源的方式

（1）通过数组资源文件指定

package com.ouc.wkp.ui1;

import android.app.Activity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;

import org.w3c.dom.Text;

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

/**
* Created by wkp on 2016/8/23.
*/
public class JustLook4 extends Activity {

List<UserInfo> dataList;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.listview_index);

//获取ListView
ListView demoListView = (ListView) findViewById(R.id.my_list_view);

//使用simpleAdapter
//创建数据源对象（第二个参数）
//        List<Map<String,?>> dataList=new ArrayList<>();
//        for(int i=0;i<50;i++){
//            Map<String,String> map=new HashMap<>();
//            map.put("name","张三"+i);
//            map.put("sex",i%2==0?"男":"女");
//            map.put("age",10+i+"");
//            dataList.add(map);
//        }
//
//        String[] from={"name","sex","age"};
//        int[] to={R.id.tv_name,R.id.tv_sex,R.id.tv_age};
//
//        SimpleAdapter simpleAdapter=new SimpleAdapter(this,dataList,R.layout.item_userinfo,from,to);
//        demoListView.setAdapter(simpleAdapter);

//使用BaseAdapter
dataList = new ArrayList<>();
for (int i = 0; i < 50; i++) {
UserInfo userInfo = new UserInfo();
userInfo.name = "张三" + i;
userInfo.sex = i % 2 == 0 ? "男" : "女";
userInfo.age = 10 + i;
dataList.add(userInfo);
}

UserInfoListAdapter userInfoListAdapter = new UserInfoListAdapter();
demoListView.setAdapter(userInfoListAdapter);
}

class UserInfoListAdapter extends BaseAdapter {

@Override
public int getCount() {
return dataList.size();
}

@Override
public Object getItem(int i) {
return dataList.get(i);
}

@Override
public long getItemId(int i) {
return i;
}

@Override
public View getView(int i, View view, ViewGroup viewGroup) {
View itemRootView = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.item_userinfo, null);

TextView tvName = (TextView) itemRootView.findViewById(R.id.tv_name);
tvName.setText(dataList.get(i).name);
TextView tvSex = (TextView) itemRootView.findViewById(R.id.tv_sex);
tvSex.setText(dataList.get(i).sex);
TextView tvAge = (TextView) itemRootView.findViewById(R.id.tv_age);
tvAge.setText(dataList.get(i).age + "");

ImageView imageViewSex = (ImageView) itemRootView.findViewById(R.id.image_view_sex);
if (dataList.get(i).sex.equals("男")) {
imageViewSex.setBackgroundResource(R.drawable.male);
} else if (dataList.get(i).sex.equals("女")) {
imageViewSex.setBackgroundResource(R.drawable.female);
}

return itemRootView;
}
}

class UserInfo {
String name;
String sex;
int age;
}
}

JustLook4.java
我们需要写一个类实现BaseAdapter抽象类，最主要的是getView方法，运行效果如下