上文降到了db数据包中数据库模型相关代码的编写，下面继续编写
遍历全国市县数据
1. 工具类编写
在util包下增加一个HttpUtil类用户处理发起的HTTP请求
public class HttpUtil {
public static void sendOkHttpRequest(String address, okhttp3.Callback callback) {
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder().url(address).build();
client.newCall(request).enqueue(callback);
}
}
在util包下增加一个Utility类用于处理JSON格式的数据
public class Utility {
/*
* 解析处理返回的省级数据
* @param response 返回的数据
* @return
*/
public static boolean handleProvinceResponse(String response) {
if (!TextUtils.isEmpty(response)) {
try {
JSONArray allProvinces = new JSONArray(response);
for (int i = 0; i < allProvinces.length(); i++) {
JSONObject provinceObject = allProvinces.getJSONObject(i);
Province province = new Province();
province.setProvinceName(provinceObject.getString("name"));
province.setProvinceCode(provinceObject.getInt("id"));
province.save();
}
return true;
} catch (JSONException e) {
e.printStackTrace();
}
}
return false;
}
/**
* 解析处理返回的市级数据
*
* @param response 返回的市级数据
* @param provinceId 省id
* @return
*/
public static boolean handleCityResponse(String response, int provinceId) {
if (!TextUtils.isEmpty(response)) {
try {
JSONArray allCtities = new JSONArray(response);
for (int i = 0; i < allCtities.length(); i++) {
JSONObject cityObject = allCtities.getJSONObject(i);
City city = new City();
city.setCityName(cityObject.getString("name"));
city.setCityCode(cityObject.getInt("id"));
city.setProvinceId(provinceId);
city.save();
}
return true;
} catch (JSONException e) {
e.printStackTrace();
}
}
return false;
}
/**
* 解析处理返回的县级数据
*
* @param response 返回值
* @param cityId 市id
* @return
*/
public static boolean handleCountyResponse(String response, int cityId) {
if (!TextUtils.isEmpty(response)) {
try {
JSONArray allCounties = new JSONArray(response);
for (int i = 0; i < allCounties.length(); i++) {
JSONObject countyObject = allCounties.getJSONObject(i);
County county = new County();
county.setCountyName(countyObject.getString("name"));
county.setWeatherId(countyObject.getString("weather_id"));
county.setCityId(cityId);
county.save();
}
return true;
} catch (JSONException e) {
e.printStackTrace();
}
}
return false;
}
}
提供如上三个方法用于解析返回的数据，县通过JSONArray和JSONObject将数据解析出来，然后组装成实体类对象，在调用save()方法将数据保存在数据库中。
2. 业务逻辑及页面
在res/layout目录下新建choose_area.xml布局，如下：
<?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"
android:background="#fff">
<!--定义一个头部居作为标题栏 高度设置为actionBar-->
<!--在头部居放置一个TextView同于显示标题内容，放置一个Button用于执行返回操作-->
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary">
<TextView
android:id="@+id/title_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:textColor="#fff"
android:textSize="20sp"/>
<Button
android:id="@+id/back_button"
android:layout_width="25dp"
android:layout_height="25dp"
android:layout_marginLeft="10dp"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true"
android:background="@drawable/ic_back"/>
</RelativeLayout>
<!--头布局下定义了一个ListView,用于显示省市县数据-->
<ListView
android:id="@+id/list_view"
android:layout_width="match_parent"
android:layout_height="match_parent"></ListView>
</LinearLayout>
新建ChooseAreaFragment，继承自Fragment
public class ChooseAreaFragment extends Fragment {
public static final int LEVEL_PROVINCE = 0;
public static final int LEVEL_CITY = 1;
public static final int LEVEL_COUNTY = 2;
private ProgressDialog progressDialog; //进度对话框
private TextView titleText;
private Button backButton;
private ListView listView;
private ArrayAdapter<String> adapter;
private List<String> dataList = new ArrayList<>();
/**
* 省列表
*/
private List<Province> provinceList;
/**
* 市列表
*/
private List<City> cityList;
/**
* 县列表
*/
private List<County> countyList;
/**
* 选中和省份
*/
private Province selectedProvince;
/**
* 选中的市
*/
private City selectedCity;
/**
* 当前选中的级别
*/
private int currentLevel;
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.choose_area, container, false);
titleText = (TextView) view.findViewById(R.id.title_text);
backButton = (Button) view.findViewById(R.id.back_button);
listView = (ListView) view.findViewById(R.id.list_view);
adapter = new ArrayAdapter<>(getContext(), android.R.layout.simple_list_item_1, dataList);
listView.setAdapter(adapter);
return view;
}
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
if (currentLevel == LEVEL_PROVINCE) {
selectedProvince = provinceList.get(position);
queryCities();
} else if (currentLevel == LEVEL_CITY) {
selectedCity = cityList.get(position);
queryCounties();
}
}
});
backButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (currentLevel == LEVEL_COUNTY) {
queryCities();
} else if (currentLevel == LEVEL_CITY) {
queryProvinces();
}
}
});
queryProvinces();
}
/**
* 查询全国所有的省，优先从数据库中查询，如果没有查询到再去服务器上查询
*/
private void queryProvinces() {
titleText.setText("中国");
backButton.setVisibility(View.GONE);
Log.d("12312312312", "2");
provinceList = DataSupport.findAll(Province.class);
if (provinceList.size() > 0) {
dataList.clear();
for (Province province : provinceList) {
dataList.add(province.getProvinceName());
}
adapter.notifyDataSetChanged();
listView.setSelection(0);
currentLevel = LEVEL_PROVINCE;
} else {
String address = "http://guolin.tech/api/china";
queryFromServer(address, "province");
}
}
private void queryCities() {
titleText.setText(selectedProvince.getProvinceName());
backButton.setVisibility(View.VISIBLE);
cityList = DataSupport.where("provinceid=?",
String.valueOf(selectedProvince.getId())).find(City.class);
if (cityList.size() > 0) {
dataList.clear();
for (City city : cityList) {
dataList.add(city.getCityName());
}
adapter.notifyDataSetChanged();
listView.setSelection(0);
currentLevel = LEVEL_CITY;
} else {
int provinceCode = selectedProvince.getProvinceCode();
String address = "http://guolin.tech/api/china/" + provinceCode;
queryFromServer(address, "city");
}
}
private void queryCounties() {
titleText.setText(selectedCity.getCityName());
backButton.setVisibility(View.VISIBLE);
countyList = DataSupport.where("cityid = ?",
String.valueOf(selectedCity.getId())).find(County.class);
if (countyList.size() > 0) {
dataList.clear();
for (County county : countyList) {
dataList.add(county.getCountyName());
}
listView.setSelection(0);
currentLevel = LEVEL_COUNTY;
} else {
int provinceCode = selectedProvince.getProvinceCode();
int cityCode = selectedCity.getCityCode();
String address = "http://guolin.tech/api/china/" + provinceCode + "/" + cityCode;
queryFromServer(address, "county");
}
}
/**
* 根据传入的地址和类型查询出省市县数据
*
* @param address 地址
* @param type 类型
*/
private void queryFromServer(String address, final String type) {
showProgressDialog();
Log.d("12312312312", "1");
HttpUtil.sendOkHttpRequest(address, new Callback() {
@Override
public void onFailure(Call call, IOException e) {
//通过 runOnUiThread() 方法回到主线程处理逻辑
getActivity().runOnUiThread(new Runnable() {
@Override
public void run() {
closeProgressDialog();
Toast.makeText(getContext(), "加载失败", Toast.LENGTH_SHORT)
.show();
}
});
}
@Override
public void onResponse(Call call, Response response) throws IOException {
String responseText = response.body().string();
boolean result = false;
if ("province".equals(type)) {
result = Utility.handleProvinceResponse(responseText);
} else if ("city".equals(type)) {
result = Utility.handleCityResponse(responseText, selectedProvince.getId());
} else if ("county".equals(type)) {
result = Utility.handleCountyResponse(responseText, selectedCity.getId());
}
if (result) {
getActivity().runOnUiThread(new Runnable() {
@Override
public void run() {
closeProgressDialog();
if ("province".equals(type)) {
queryProvinces();
} else if ("city".equals(type)) {
queryCities();
} else if ("county".equals(type)) {
queryCounties();
}
}
});
}
}
});
}
/**
* 显示进度对话框
*/
private void showProgressDialog() {
if (progressDialog == null) {
progressDialog = new ProgressDialog(getActivity());
progressDialog.setMessage("正在加载...");
progressDialog.setCanceledOnTouchOutside(false);
}
progressDialog.show();
}
private void closeProgressDialog() {
if (progressDialog != null) {
progressDialog.dismiss();
}
}
}
以上代码看似非常多，但是逻辑不复杂，慢慢梳理肯定会看懂的。
碎片不能直接显示在页面上，因此我们需要把它添加到活动中，修改activity_main.xml代码，如下：
<fragment
android:id="@+id/choose_area_fragment"
android:name="com.example.dean.deanweather.ChooseAreaFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"></fragment>
另外，我们在碎片布局中自定义了标题栏，，因此就不需要原生的ActionBar了，修改res/values/styles.xml中代码，如下：
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
...
</style>
最后添加网路权限。修改AndroidManifest.xml中代码，如下：
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.dean.deanweather">
<!--网络权限-->
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
...
</manifest>
运行程序，效果如下：
效果图
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