最好用的Android省市区三级联动选择效果

砸漏

发布于 2020-11-04 11:46:19

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发布于 2020-11-04 11:46:19

文章被收录于专栏：恩蓝脚本

Android省市区选择三级联动效果，一个不大不小的功能，就算你做过，但是没有相关的代码直接写，也要花掉你至少半天时间。

下面我写出我的实现过程（思路绝对清晰）。

先上效果图

一、准备数据

我是用的本地的json数据（走网络的话太慢，每次都要请求），放在asserts中。格式如下：

[{ 
 "name": "河北省", 
 "city": [ 
  { 
  "name": "石家庄市", 
  "area": [ 
   "长安区", 
   "桥东区", 
   "桥西区", 
   "新华区", 
   "郊 区", 
   "井陉矿区", 
   "井陉县", 
   "正定县", 
   "栾城县", 
   "行唐县", 
   "灵寿县", 
   "高邑县", 
   "深泽县", 
   "赞皇县", 
   "无极县", 
   "平山县", 
   "元氏县", 
   "赵 县", 
   "辛集市", 
   "藁", 
   "晋州市", 
   "新乐市", 
   "鹿泉市" 
  ] 
  },......]

二、解析数据

首先根据json生成Province对象

然后通过getAssets().open(“citylist.json”);获取文件输入流，接着转成字节，最终获取字符串。

然后用Gson解析字符串得到Province的List对象。由于读文件是IO操作，这里我用了RxJava，代码如下：

/** 
  * 从assert文件夹中获取json数据 
  */ 
 private void initJsonData() { 
 
  Observable.create(new ObservableOnSubscribe<List<Province  () { 
   @Override 
   public void subscribe(ObservableEmitter<List<Province   emitter) throws Exception { 
    List<Province  provinces = new ArrayList< (); 
    try { 
     StringBuffer sb = new StringBuffer(); 
     InputStream is = getAssets().open("citylist.json");//打开json数据 
     byte[] by = new byte[is.available()];//转字节 
     int len = -1; 
     while ((len = is.read(by)) != -1) { 
      sb.append(new String(by, 0, len, "utf8"));//根据字节长度设置编码 
     } 
     is.close();// 关闭流 
     // 通过Gson将字符串转成对象list 
     Gson gson = new Gson(); 
     provinces = gson.fromJson(sb.toString(), new TypeToken<List<Province  () { 
     }.getType()); 
    } catch (Exception e) { 
     e.printStackTrace(); 
    } finally { 
     emitter.onNext(provinces); 
    } 
   } 
  }).subscribeOn(Schedulers.io()) 
    .observeOn(AndroidSchedulers.mainThread()) 
    .subscribe(new Consumer<List<Province  () { 
     @Override 
     public void accept(List<Province  provinces) throws Exception { 
      if (provinces != null && provinces.size()   0) { 
       RegionSelectActivity.this.provinces = provinces; 
       // 显示数据 
       showData(); 
      } 
     } 
    }); 
 }

三、显示数据

RxJava异步读取数据后就可以显示了，这里用了三个Spinner来分别显示省，市，区数据。

显示的思路大家都清楚，这里不再赘述，代码如下

/** 
  * 展示数据 
  */ 
 private void showData() { 
  for (Province province : provinces) { 
   provinceList.add(province.getName()); 
  } 
  // 显示省份数据 
  spProvince.setAdapter(new ArrayAdapter<String (this, android.R.layout.simple_spinner_item, provinceList)); 
  spProvince.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() { 
   @Override 
   public void onItemSelected(AdapterView<?  parent, View view, int position, long id) { 
    provincePosition = position; 
    provinceName = provinceList.get(position); 
    // 获取当前省份对应的城市list 
    cityList.clear(); 
    List<Province.CityBean  cityBeans = provinces.get(position).getCity(); 
    for (Province.CityBean city : cityBeans) { 
     cityList.add(city.getName()); 
    } 
    // 刷新城市列表 
    spCity.setSelection(0); 
    cityName = cityList.get(0); 
    cityAdapter.notifyDataSetChanged(); 
 
    // 刷新城区列表 
    updateArea(0); 
   } 
 
   @Override 
   public void onNothingSelected(AdapterView<?  parent) { 
 
   } 
  }); 
 
  // 显示城市数据 
  spCity.setAdapter(cityAdapter = new ArrayAdapter<String (this, android.R.layout.simple_spinner_item, cityList)); 
  spCity.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() { 
   @Override 
   public void onItemSelected(AdapterView<?  parent, View view, int position, long id) { 
    cityPosition = position; 
    cityName = cityList.get(position); 
    // 刷新城区列表 
    updateArea(position); 
   } 
 
   @Override 
   public void onNothingSelected(AdapterView<?  parent) { 
 
   } 
  }); 
 
  // 显示城区数据 
  spArea.setAdapter(areaAdapter = new ArrayAdapter<String (this, android.R.layout.simple_spinner_item, areaList)); 
  spArea.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() { 
   @Override 
   public void onItemSelected(AdapterView<?  parent, View view, int position, long id) { 
    areaName = areaList.get(position); 
   } 
 
   @Override 
   public void onNothingSelected(AdapterView<?  parent) { 
 
   } 
  });