使用PickerView实现地区：省-市-区、三级联动功能

引言

  很多时候我们都会在各种app上看到地区选择的功能，今天就来使用PickerView来实现地区三级联动的选择器功能。
  本篇与通过接口解析地区数据的方式不同，而是采用解析本地地区json文件的方式来解析数据。也就是说，无需网络连接解析接口，而是直接通过本地工具类解析json文件。话不多说，快来看看怎么实现吧！

效果预览

用法

步骤一、引入第三方依赖库

在app下build.gradle中添加如下依赖：

//PickerView库
implementation 'com.contrarywind:Android-PickerView:4.1.9'

步骤二、布局文件

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".blog.Case46"
        tools:ignore="MissingConstraints">
       
    <Button
        android:id="@+id/btnAreaPicker"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="10dp"
        android:background="@color/green"
        android:text="地区三级联动"
        android:textColor="@color/white"
        android:textSize="18sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

步骤三、添加地区json文件

请移步github中下载该文件
传送门：地区（省-市-区）json文件
添加到AndroidStudio中：app——main——src——assets文件夹中

步骤四、创建DataBean类

/**
 * @data on 2020/11/2 3:30 PM
 * @auther armStrong
 * @describe 地区json解析类
 */
public class ProviceBean {

    /**
     * name : 北京市
     * city : [{"name":"北京市","area":["东城区","西城区","崇文区","宣武区","朝阳区","丰台区","石景山区","海淀区","门头沟区","房山区","通州区","顺义区","昌平区","大兴区","平谷区","怀柔区","密云县","延庆县"]}]
     */

    private String name;
    private List<CityBean> city;

    public String getName() {
        return name;
    }

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

    public List<CityBean> getCity() {
        return city;
    }

    public void setCity(List<CityBean> city) {
        this.city = city;
    }

    public static class CityBean {
        /**
         * name : 北京市
         * area : ["东城区","西城区","崇文区","宣武区","朝阳区","丰台区","石景山区","海淀区","门头沟区","房山区","通州区","顺义区","昌平区","大兴区","平谷区","怀柔区","密云县","延庆县"]
         */

        private String name;
        private List<String> area;

        public String getName() {
            return name;
        }

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

        public List<String> getArea() {
            return area;
        }

        public void setArea(List<String> area) {
            this.area = area;
        }
    }
}

步骤五、解析数据工具类

/**
 * @data on 2020/11/2 3:32 PM
 * @auther armStrong
 * @describe 读取Assent资源文件中的并将.json文件转换成String类型
 */
public class GetJsonDataUtil {
    public String getJson(Context context, String fileName) {

        StringBuilder stringBuilder = new StringBuilder();
        try {
            AssetManager assetManager = context.getAssets();
            BufferedReader bf = new BufferedReader(new InputStreamReader(
                    assetManager.open(fileName)));
            String line;
            while ((line = bf.readLine()) != null) {
                stringBuilder.append(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return stringBuilder.toString();
    }

}

步骤六、在Activity中书写业务逻辑代码

public class Case46 extends AppCompatActivity {
    private Button btnAreaPicker;
    //省、市、区-列表
    private List<String> options1Items = new ArrayList<>();
    private List<List<String>> options2Items = new ArrayList<>();
    private List<List<List<String>>> options3Items = new ArrayList<>();


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_case46);
        //初始化
        initView();
        //弹出选择器
        getView();
        //填充数据
        initJsonData();
    }

    private void initView() {
        btnAreaPicker = findViewById(R.id.btnAreaPicker);
    }

    private void getView() {
        btnAreaPicker.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                areaPicker();
            }
        });
    }

    /**
     *  PickerView用法
     */
    private void areaPicker() {
        OptionsPickerView pvOptions = new OptionsPickerBuilder(this, new OnOptionsSelectListener() {
            @Override
            public void onOptionsSelect(int options1, int options2, int options3, View v) {
                String str = options1Items.get(options1) +
                        options2Items.get(options1).get(options2) +
                        options3Items.get(options1).get(options2).get(options3);
                ToastUtils.show(str);
            }
        })
                .setTitleText("城市选择")
                .setDividerColor(Color.BLACK)
                .setTextColorCenter(Color.BLACK)
                .setContentTextSize(20)
                .setOutSideCancelable(false)
                .build();
        pvOptions.setPicker(options1Items, options2Items, options3Items);
        pvOptions.show();
    }

    /**
     *  解析数据
     */
    private void initJsonData() {
        String str = new GetJsonDataUtil().getJson(this, "province.json");
        List<ProviceBean> list = new Gson().fromJson(str, new TypeToken<List<ProviceBean>>() {
        }.getType());
        for (ProviceBean bean : list) {
            options1Items.add(bean.getName());
            List<String> city = new ArrayList<>();
            List<List<String>> area = new ArrayList<>();
            for (ProviceBean.CityBean cityBean : bean.getCity()) {
                city.add(cityBean.getName());
                area.add(cityBean.getArea());
            }
            options2Items.add(city);
            options3Items.add(area);
        }
    }
}

大功告成！