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

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string-array name="grade">
        <item>小学一年级</item>
        <item>小学二年级</item>
        <item>小学三年级</item>
        <item>小学四年级</item>
        <item>小学五年级</item>
        <item>小学六年级</item>
        <item>初中一年级</item>
        <item>初中二年级</item>
    </string-array>
</resources>

arrays.xml

布局文件

<?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">

    <Spinner
        android:id="@+id/my_spinner"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:entries="@array/grade"></Spinner>
</LinearLayout>

spinner_index.xml

运行效果

（2）通过java代码指定

package com.ouc.wkp.ui1;

import android.app.Activity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.Spinner;

/**
 * Created by wkp on 2016/8/23.
 */
public class JustLook3 extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.spinner_index);

        //通过java代码设置数据源
        Spinner spinner = (Spinner) findViewById(R.id.my_spinner);

        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, R.layout.support_simple_spinner_dropdown_item, android.R.id.text1, new String[]{"小学一年级", "小学二年级", "小学三年级"});

        spinner.setAdapter(adapter);
    }
}

JustLook3.java

ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, R.layout.support_simple_spinner_dropdown_item, android.R.id.text1, new String[]{"小学一年级", "小学二年级", "小学三年级"});

spinner.setAdapter(adapter);

关键这两行，布局文件可以不变，运行效果如下

二、ListView控件(ArrayAdapter SimpleAdapter BaseAdapter赋值)
同样也是类似的两种赋值方式,使用方式基本相同

<?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">

    <ListView
        android:id="@+id/my_list_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:divider="#f00"
        android:dividerHeight="10px"
        android:scrollbars="none"
        android:overScrollMode="never"></ListView>
</LinearLayout>

listview_index.xml

package com.ouc.wkp.ui1;

import android.app.Activity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.ListView;

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

    String[] strings={
            "也还好还好",
            "adj las d",
            "也还好还好",
            "也还好还好",
            "也还好还好",
            "也还好还好",
            "也还好还好",
            "也还好还好",
            "也还好还好",
            "也还好还好",
            "也还好还好",
            "也还好还好",
            "也还好还好",
            "也还好还好",
            "也还好还好",

    };

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

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

        ArrayAdapter<String> adapter=new ArrayAdapter<String>(this,R.layout.support_simple_spinner_dropdown_item,android.R.id.text1,strings);

        demoListView.setAdapter(adapter);
    }
}

JustLook4.java

上面是使用ArrayAdapter填充数据，下面使用SimpleAdapter填充数据,(listview_index.xml不变）

先是listview的布局文件

<?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/tv_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <TextView
        android:id="@+id/tv_sex"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <TextView
        android:id="@+id/tv_age"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
</LinearLayout>

item_userinfo.xml

赋值代码

package com.ouc.wkp.ui1;

import android.app.Activity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;

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{

    String[] strings={
            "也还好还好",
            "adj las d",
            "也还好还好",
    };

    @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);

        //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);
    }
}

JustLook4.java

运行效果，空白区是因为图片没有指定资源

下面使用BaseAdapter填充数据

<?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">

    <ImageView
        android:id="@+id/image_view_sex"
        android:layout_width="60dp"
        android:layout_height="60dp" />

    <TextView
        android:id="@+id/tv_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <TextView
        android:id="@+id/tv_sex"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <TextView
        android:id="@+id/tv_age"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
</LinearLayout>

item_userinfo.xml

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