Android加载三级地址

我们在开发APP的时候，经常会遇到需要填写地址信息的情况。废话不多说，按照以下步骤实现三级地址的自动填写

第一步：从网上下载一个三级地址的json文件，放入Android Studio项目的assets文件夹下。json文件的内容如下所示（以北京为例）

"area": "010", 
        "cities": [
            {
                "area": "010", 
                "cities": [ ], 
                "code": "110101", 
                "level": 2, 
                "name": "东城区", 
                "prefix": "区"
            }, 
            {
                "area": "010", 
                "cities": [ ], 
                "code": "110102", 
                "level": 2, 
                "name": "西城区", 
                "prefix": "区"
            }, 
            {
                "area": "010", 
                "cities": [ ], 
                "code": "110105", 
                "level": 2, 
                "name": "朝阳区", 
                "prefix": "区"
            }, 
            {
                "area": "010", 
                "cities": [ ], 
                "code": "110106", 
                "level": 2, 
                "name": "丰台区", 
                "prefix": "区"
            }, 
            {
                "area": "010", 
                "cities": [ ], 
                "code": "110107", 
                "level": 2, 
                "name": "石景山区", 
                "prefix": "区"
            }, 
            {
                "area": "010", 
                "cities": [ ], 
                "code": "110108", 
                "level": 2, 
                "name": "海淀区", 
                "prefix": "区"
            }, 
            {
                "area": "010", 
                "cities": [ ], 
                "code": "110109", 
                "level": 2, 
                "name": "门头沟区", 
                "prefix": "区"
            }, 
            {
                "area": "010", 
                "cities": [ ], 
                "code": "110111", 
                "level": 2, 
                "name": "房山区", 
                "prefix": "区"
            }, 
            {
                "area": "010", 
                "cities": [ ], 
                "code": "110112", 
                "level": 2, 
                "name": "通州区", 
                "prefix": "区"
            }, 
            {
                "area": "010", 
                "cities": [ ], 
                "code": "110113", 
                "level": 2, 
                "name": "顺义区", 
                "prefix": "区"
            }, 
            {
                "area": "010", 
                "cities": [ ], 
                "code": "110114", 
                "level": 2, 
                "name": "昌平区", 
                "prefix": "区"
            }, 
            {
                "area": "010", 
                "cities": [ ], 
                "code": "110115", 
                "level": 2, 
                "name": "大兴区", 
                "prefix": "区"
            }, 
            {
                "area": "010", 
                "cities": [ ], 
                "code": "110116", 
                "level": 2, 
                "name": "怀柔区", 
                "prefix": "区"
            }, 
            {
                "area": "010", 
                "cities": [ ], 
                "code": "110117", 
                "level": 2, 
                "name": "平谷区", 
                "prefix": "区"
            }, 
            {
                "area": "010", 
                "cities": [ ], 
                "code": "110228", 
                "level": 2, 
                "name": "密云县", 
                "prefix": "区"
            }, 
            {
                "area": "010", 
                "cities": [ ], 
                "code": "110229", 
                "level": 2, 
                "name": "延庆县", 
                "prefix": "区"
            }
        ], 
        "code": "110000", 
        "level": 1, 
        "name": "北京市", 
        "prefix": "市"

第二步：根据自己的需要，创建一个java bean类，用来存放城市信息。

public class CityInfo {

    //城市代码
    private String code;
    //城市名称
    private String name;
    //城市的下级城市
    private String cities;

    public CityInfo(String cities, String code, String name) {
        this.cities = cities;
        this.code = code;
        this.name = name;
    }

    public String getCities() {
        return cities;
    }

    public String getCode() {
        return code;
    }

    public String getName() {
        return name;
    }
}

第三步：提取json文件当中的内容

 //将json文件转为String类型
 public static String getJson(Context context) {
        StringBuilder stringBuilder = new StringBuilder();
        try {
            BufferedReader bf = new BufferedReader(new InputStreamReader(
                    context.getAssets().open(CityEntry.FILE_NAME)));
            String line;
            while ((line = bf.readLine()) != null) {
                stringBuilder.append(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return stringBuilder.toString();
    }

/**
     * 将JSON字符串转化为Adapter数据
     *
     * @param str  
     */
    public static List<CityInfo> setData(String str) {
        List<CityInfo> data = new ArrayList<>();
        try {
            JSONArray array = new JSONArray(str);
            int len = array.length();

            for (int i = 0; i < len; i++) {
                JSONObject object = array.getJSONObject(i);
                if ((object.has(CityEntry.KEY_CITY)) &&
                        (object.has(CityEntry.KEY_NAME)) &&
                        (object.has(CityEntry.KEY_CODE))) {
                    data.add(new CityInfo(
                            object.getString(CityEntry.KEY_CITY),
                            object.getString(CityEntry.KEY_CODE),
                            object.getString(CityEntry.KEY_NAME)));
                }
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return data;
    }

    private static class CityEntry {
        //json文件的文件名
        private static final String FILE_NAME = "city_code.json";
        //根据项目所需的键值
        private static final String KEY_CODE = "code";
        private static final String KEY_NAME = "name";
        private static final String KEY_CITY = "cities";

    }

最后，将setData返回的list作为adapter的参数即可显示城市信息了。
json文件可以去网上下载，如有需要可以留下邮箱。