【达内课程】xml实现省份联动

效果图

提前预习

https://blog.csdn.net/u010356768/article/details/81938244
https://blog.csdn.net/u010356768/article/details/81973981

代码

provinces.xml

<Provinces>
   <Province ID="1" ProvinceName="北京市">北京市</Province>
   <Province ID="2" ProvinceName="天津市">天津市</Province>
   <Province ID="3" ProvinceName="河北省">河北省</Province>
   <Province ID="4" ProvinceName="山西省">山西省</Province>
   <Province ID="5" ProvinceName="内蒙古自治区">内蒙古自治区</Province>
</Provinces>

cities.xml

<Cities>
   <City ID="1" CityName="北京" PID="1" ZipCode="100000">北京</City>
   <City ID="2" CityName="天津" PID="2" ZipCode="100000">天津</City>
   <City ID="3" CityName="石家庄" PID="3" ZipCode="050000">石家庄</City>
   <City ID="4" CityName="唐山" PID="3" ZipCode="063000">唐山</City>
   <City ID="5" CityName="秦皇岛" PID="3" ZipCode="066000">秦皇岛</City>
   <City ID="14" CityName="太原" PID="4" ZipCode="030000">太原</City>
   <City ID="15" CityName="大同" PID="1" ZipCode="037000">大同</City>
   <City ID="25" CityName="呼和浩特" PID="5" ZipCode="010000">呼和浩特</City>
</Cities>

Province.java来描述一个省份

public class Province {
    private int id;
    private String name;

    public Province() {
    }

    public Province(int id, String name) {
        this.id = id;
        this.name = name;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return this.name;
    }
}

City.java来描述一个城市

public class City {
    private int id;
    private int pid;
    private String name;

    public City() {
    }

    public City(int id, int pid, String name) {
        this.id = id;
        this.pid = pid;
        this.name = name;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public int getPid() {
        return pid;
    }

    public void setPid(int pid) {
        this.pid = pid;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return this.name;
    }
}

布局文件activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="300dp">
        <ListView
            android:id="@+id/lvProvince"
            android:layout_width="0dp"
            android:layout_height="300dp"
            android:layout_weight="1"
            />
        <ListView
            android:id="@+id/lvCity"
            android:layout_width="0dp"
            android:layout_height="300dp"
            android:layout_weight="1"
            />
    </LinearLayout>

</LinearLayout>

MainActivity

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Xml;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;

import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
import org.xmlpull.v1.XmlPullParser;

import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;


public class MainActivity extends AppCompatActivity {
    private ListView lvProvince;
    private ListView lvCity;
    List<Province> provinces;
    private List<City> allCities;
    private List<City> cities = new ArrayList<City>();

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

        setViews();

        try {
            //解析省份的xml
            parseAndLoadProvince();
            parseCity();
        } catch (Exception e) {
            e.printStackTrace();
        }

        setListeners();
    }


    /**
     * 设置监听
     */
    private void setListeners() {
        lvProvince.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
                //获取当前选中的是哪个省份
                Province p = provinces.get(i);
                int pid = p.getId();
                //遍历allCities 过滤所有需要的城市数据
                cities.clear();
                for(City c:allCities){
                    if(c.getPid() == pid){
                        cities.add(c);
                    }
                }
                //更新adapter
                ArrayAdapter<City> city = new ArrayAdapter<City>(MainActivity.this,android.R.layout.simple_list_item_1,cities);
                lvCity.setAdapter(city);
            }
        });
    }

    /**
     * 解析所有城市数据并保存到成员变量
     * 适合使用PULL解析
     */
    private void parseCity() throws Exception {
        XmlPullParser parser = Xml.newPullParser();
        InputStream is = getAssets().open("cities.xml");
        parser.setInput(is, "utf-8");
        int type = parser.getEventType();
        allCities = new ArrayList<City>();
        City city = null;
        while (type != XmlPullParser.END_DOCUMENT) {
            switch (type) {
                //碰到了开始标记
                case XmlPullParser.START_TAG:
                    String name = parser.getName();
                    if (name.equals("City")) {//创建对象
                        city = new City();
                        city.setId(Integer.parseInt(parser.getAttributeValue(0)));
                        city.setName(parser.getAttributeValue(1));
                        city.setPid(Integer.parseInt(parser.getAttributeValue(2)));
                        allCities.add(city);
                    }
                    break;
                default:
                    break;
            }
            type = parser.next();
        }
    }

    /**
     * 解析并加载省份信息（DOM4J）
     */
    private void parseAndLoadProvince() throws Exception {
        SAXReader reader = new SAXReader();
        InputStream is = getAssets().open("provinces.xml");
        Document doc = reader.read(is);
        //获取文档根元素
        Element root = doc.getRootElement();
        List<Element> proEles = root.elements();
        provinces = new ArrayList<Province>();
        for (Element e : proEles) {
            //获取省份ID和省份名称
            String id = e.attributeValue("ID");
            String name = e.attributeValue("ProvinceName");
            Province p = new Province(Integer.parseInt(id), name);
            provinces.add(p);
        }
        //解析完毕，立即显示到界面中
        ArrayAdapter<Province> adapter = new ArrayAdapter<Province>(this, android.R.layout.simple_list_item_1, provinces);
        lvProvince.setAdapter(adapter);
    }

    private void setViews() {
        lvProvince = findViewById(R.id.lvProvince);
        lvCity = findViewById(R.id.lvCity);
    }
}