Android天气预报app改进版

最近总是有人来和我说我以前写的一个小app无法正常获取数据~Android简易版天气预报app
今天就又运行了下来查找问题，发现或许是接口有限制吧，不能在多台手机使用同个apikey
然后，发现了我写的代码实在乱七八糟，界面也实在不好看，就又重写了一遍，小小地修改了一遍，开发环境改为了Android Studio

最终效果图如下

工程图如下

一、获取地区信息

做这么一个天气预报app，首先就要获取到国内地区列表
（在我的另一篇博客有介绍：向任意网址发起数据请求）
中国天气网开放有天气预报接口，访问“http://www.weather.com.cn/data/list3/city.xml”就可以获取到国内省份列表以及其代号了

如果想要获取广东省下的城市列表，由上图可知广东省的代号为28，则接口地址是 “http://www.weather.com.cn/data/list3/city28.xml”，获取到的城市列表及代号如下：

依次类推还可以获取到更加详细的地区信息，这样就完成了开头部分

二、天气信息的获取

百度的APIStore拥有丰富的接口，涵盖了生活的许多方面。例如，我们就可以通过APIStore的某个接口获取到含有天气信息的JSON数据，从而实现天气预报功能
(在我的另一篇博客有介绍：获取含天气信息的JSON数据)
首先，使用者要有一个百度账号，然后登陆以下网址：中国和世界天气预报
该接口是免费的，不过因此也就不够稳定，我在调试的时候就经常出错
然后在API选项下点击“您自己的apikey”，查看自己的apikey。该值是每个开发者和app的唯一标识，需要妥善保管，有了apikey才可以进行下一步的操作

获取到的天气信息是JSON格式的，需要在程序中再来解析

三、数据库的设计

地区列表这些信息一般都是固定不变的，所以我们可以把第一次联网获取到的数据存进数据库里，下次再次访问时就从数据库里读取即可
首先要设定四个Model，包括：省份、城市、县、每小时天气预测，用来承载数据
每个Model包括几个属性以及相应的get和set方法
例如，省份Province的设计如下所示，城市City和县County的设计类似

/**
 * 省份
 */
public class Province {
 //省份名
 private String provinceName;
 //省份ID
 private String provinceId;

 public String getProvinceId() {
  return provinceId;
 }

 public String getProvinceName() {
  return provinceName;
 }

 public void setProvinceId(String provinceId) {
  this.provinceId = provinceId;
 }

 public void setProvinceName(String provinceName) {
  this.provinceName = provinceName;
 }
}

每小时天气预测HourlyWeather的设计如下：

/**
 * Created by ZY on 2016/7/21.
 */
public class HourlyWeather {

 //预测时间
 private String time;
 //温度
 private String temp;
 //降水概率
 private String pop;
 //风力
 private String wind;

 public HourlyWeather(String time, String temp, String pop, String wind) {
  this.time = time;
  this.temp = temp;
  this.pop = pop;
  this.wind = wind;
 }

 public String getTime() {
  return time;
 }

 public String getTemp() {
  return temp;
 }

 public String getPop() {
  return pop;
 }

 public String getWind() {
  return wind;
 }
}

然后，新建一个DatabaseHelper类继承于SQLiteOpenHelper，用来建立三个数据库表

public class DatabaseHelper extends SQLiteOpenHelper {

 private final String CREATE_PROVINCE = "create table Province ("
   + "provinceName text," + "provinceId text )";

 private final String CREATE_CITY = "create table City("
   + "cityName text," + "cityId text," + "provinceId text)";

 private final String CREATE_COUNTY = "create table County("
   + "countyName text," + "countyId text," + "cityId text)";

 public DatabaseHelper(Context context, String DbName,
       CursorFactory factory, int version) {
  super(context, DbName, factory, version);
 }

 @Override
 public void onCreate(SQLiteDatabase db) {
  db.execSQL(CREATE_PROVINCE);
  db.execSQL(CREATE_CITY);
  db.execSQL(CREATE_COUNTY);
 }

 @Override
 public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

 }

}

然后，再建立一个WeatherDB类，用来进行实际的数据库操作，包括存取省份信息、城市信息、县信息等
需要注意的是，因为每个城市都是包含在某个省份下的，所以查询某个省份下的所有城市列表，需要将省份的ID传入作为唯一标识

public class WeatherDB {

 private final String DataBaseName = "ZyWeather";

 private final int VERSION = 1;

 private SQLiteDatabase database;

 private static WeatherDB weatherDB;

 private WeatherDB(Context context) {
  DatabaseHelper dataBaseHelper = new DatabaseHelper(context,
    DataBaseName, null, VERSION);
  database = dataBaseHelper.getWritableDatabase();
 }

 //获取实例
 public static WeatherDB getInstance(Context context) {
  if (weatherDB == null) {
   weatherDB = new WeatherDB(context);
  }
  return weatherDB;
 }

 //保存省份信息
 public void saveProvinces(List<Province> provinceList) {
  if (provinceList != null && provinceList.size() > 0) {
   ContentValues values = new ContentValues();
   for (int i = 0; i < provinceList.size(); i++) {
    values.put("provinceName", provinceList.get(i).getProvinceName());
    values.put("provinceId", provinceList.get(i).getProvinceId());
    database.insert("Province", null, values);
    values.clear();
   }
  }
 }

 //保存城市信息
 public void saveCities(List<City> cityList) {
  if (cityList != null && cityList.size() > 0) {
   ContentValues values = new ContentValues();
   for (int i = 0; i < cityList.size(); i++) {
    values.put("cityName", cityList.get(i).getCityName());
    values.put("cityId", cityList.get(i).getCityId());
    values.put("provinceId", cityList.get(i).getProvinceId());
    database.insert("City", null, values);
    values.clear();
   }
  }
 }

 //保存乡村信息
 public void saveCounties(List<County> countyList) {
  if (countyList != null && countyList.size() > 0) {
   ContentValues values = new ContentValues();
   for (int i = 0; i < countyList.size(); i++) {
    values.put("countyName", countyList.get(i).getCountyName());
    values.put("countyId", countyList.get(i).getCountyId());
    values.put("cityId", countyList.get(i).getCityId());
    database.insert("County", null, values);
    values.clear();
   }
  }
 }

 //返回所有省份信息
 public List<Province> getAllProvince() {
  Cursor cursor = database.query("Province", null, null, null, null, null, null);
  List<Province> list = new ArrayList<>();
  Province province;
  if (cursor.moveToFirst()) {
   do {
    province = new Province();
    province.setProvinceName(cursor.getString(cursor.getColumnIndex("provinceName")));
    province.setProvinceId(cursor.getString(cursor.getColumnIndex("provinceId")));
    list.add(province);
   } while (cursor.moveToNext());
  }
  return list;
 }

 //返回指定省份下的所有城市
 public List<City> getAllCity(String provinceId) {
  List<City> list = new ArrayList<>();
  City city;
  Cursor cursor = database.query("City", null, "provinceId = ?", new String[]{provinceId}, null, null, null);
  if (cursor.moveToFirst()) {
   do {
    city = new City();
    city.setCityName(cursor.getString(cursor.getColumnIndex("cityName")));
    city.setCityId(cursor.getString(cursor.getColumnIndex("cityId")));
    city.setProvinceId(provinceId);
    list.add(city);
   } while (cursor.moveToNext());
  }
  return list;
 }

 //返回指定城市下的所有乡村
 public List<County> getAllCountry(String cityId) {
  List<County> list = new ArrayList<>();
  Cursor cursor = database.query("County", null, "cityId=?", new String[]{cityId}, null, null, null);
  County county;
  if (cursor.moveToFirst()) {
   do {
    county = new County();
    county.setCountyName(cursor.getString(cursor.getColumnIndex("countyName")));
    county.setCountyId(cursor.getString(cursor.getColumnIndex("countyId")));
    county.setCityId(cityId);
    list.add(county);
   } while (cursor.moveToNext());
  }
  return list;
 }

}

四、联网操作

整个app用同一个函数来完成各种数据数据操作，该函数包含在HttpUtil类下，为静态函数
当中需要填入自己申请的apikey，该key仅在获取天气信息时有用，在获取地区信息时是不需要的，这里只是为了简便，所以就一起写上了

public class HttpUtil {

 public static void sendHttpRequest(final String address, final HttpCallbackListener listener) {
  new Thread(new Runnable() {
   public void run() {
    HttpURLConnection connection = null;
    try {
     URL url = new URL(address);
     connection = (HttpURLConnection) url.openConnection();
     connection.setRequestMethod("GET");
     connection.setConnectTimeout(8000);
     connection.setReadTimeout(8000);
     connection.setRequestProperty("apikey", "填入自己的apikey");
     connection.connect();
     InputStream inputStream = connection.getInputStream();
     InputStreamReader inputStreamReader = new InputStreamReader(inputStream, "UTF-8");
     BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
     StringBuilder response = new StringBuilder();
     String line;
     while ((line = bufferedReader.readLine()) != null) {
      response.append(line);
     }
     if (listener != null) {
      listener.onFinish(response.toString());
     }
    } catch (Exception e) {
     if (listener != null) {
      listener.onError(e);
     }
    } finally {
     if (connection != null) {
      connection.disconnect();
     }
    }
   }
  }).start();
 }
}

五、工具类

在联网访问数据成功或失败后，都需要通过回调方法进行数据处理，所以需要设定一个接口HttpCallbackListener

public interface HttpCallbackListener {

 void onFinish(String response);

 void onError(Exception e);

}

此外，使用HttpUtil 类获取到地区信息后，因为数据包含一些分隔符，无法直接存入数据库，而且获取到的天气信息也是JSON格式的，也需要进行数据解析，所以还需要有一个Utility类用来进行数据处理

public class Utility {

 // 保存服务器返回的省级数据
 public static boolean saveProvincesResponse(WeatherDB weatherDB, String response) {
  if (!TextUtils.isEmpty(response)) {
   String[] allProvinces = response.split(",");
   if (allProvinces != null && allProvinces.length > 0) {
    Province province;
    List<Province> provinceList = new ArrayList<>();
    for (String p : allProvinces) {
     String[] array = p.split("\\|");
     province = new Province();
     province.setProvinceId(array[0]);
     province.setProvinceName(array[1]);
     provinceList.add(province);
    }
    weatherDB.saveProvinces(provinceList);
    return true;
   }
  }
  return false;
 }

 // 保存服务器返回的市级数据
 public static boolean saveCitiesResponse(WeatherDB weatherDB, String response, String provinceId) {
  if (!TextUtils.isEmpty(response)) {
   String[] allCities = response.split(",");
   if (allCities != null && allCities.length > 0) {
    City city;
    List<City> cityList = new ArrayList<>();
    for (String c : allCities) {
     String[] array = c.split("\\|");
     city = new City();
     city.setCityId(array[0]);
     city.setCityName(array[1]);
     city.setProvinceId(provinceId);
     cityList.add(city);
    }
    weatherDB.saveCities(cityList);
    return true;
   }
  }
  return false;
 }

 // 保存服务器返回的县级数据
 public static boolean saveCountiesResponse(WeatherDB weatherDB, String response, String cityId) {
  if (!TextUtils.isEmpty(response)) {
   String[] allCounties = response.split(",");
   if (allCounties != null && allCounties.length > 0) {
    County county;
    List<County> countyList = new ArrayList<>();
    for (String c : allCounties) {
     String[] array = c.split("\\|");
     county = new County();
     county.setCountyId(array[0]);
     county.setCountyName(array[1]);
     county.setCityId(cityId);
     countyList.add(county);
    }
    weatherDB.saveCounties(countyList);
    return true;
   }
  }
  return false;
 }

 // 处理服务器返回的json数据
 public static void handleWeatherResponse(Context context, String response) {
  try {
   JSONObject jsonobject = new JSONObject(response);
   JSONArray title = jsonobject.getJSONArray("HeWeather data service 3.0");
   JSONObject first_object = (JSONObject) title.get(0);

   JSONObject basic = (JSONObject) first_object.get("basic");

   //更新时间
   JSONObject update = (JSONObject) basic.get("update");
   JSONArray daily_forecast = (JSONArray) first_object.get("daily_forecast");
   JSONObject daily_forecast_first = (JSONObject) daily_forecast.get(0);
   JSONObject cond = (JSONObject) daily_forecast_first.get("cond");
   //温度
   JSONObject temp = (JSONObject) daily_forecast_first.get("tmp");

   JSONObject astro = (JSONObject) daily_forecast_first.get("astro");

   JSONObject wind = (JSONObject) daily_forecast_first.get("wind");

   JSONArray hourly_forecast = (JSONArray) first_object.get("hourly_forecast");

   WeatherActivity.weatherList.clear();

   for (int i = 0; i < hourly_forecast.length(); i++) {
    JSONObject json = hourly_forecast.getJSONObject(i);
    JSONObject json_wind = (JSONObject) json.get("wind");
    String date = json.getString("date");
    String[] array = date.split(" ");
    String dir = json_wind.getString("dir");
    String sc = json_wind.getString("sc");
    String hourly_clock = array[1];
    String hourly_temp = "温度：" + json.getString("tmp") + "℃";
    String hourly_pop = "降水概率：" + json.getString("pop");
    String hourly_wind = "风力：" + dir + " " + sc + "级";
    HourlyWeather weather = new HourlyWeather(hourly_clock, hourly_temp, hourly_pop, hourly_wind);
    WeatherActivity.weatherList.add(weather);
   }
   //日出
   String sunriseTime = astro.getString("sr");
   //日落
   String sunsetTime = astro.getString("ss");
   //白天天气
   String dayWeather = cond.getString("txt_d");
   //夜晚天气
   String nightWeather = cond.getString("txt_n");
   //风力
   String windText = wind.getString("dir") + " " + wind.getString("sc") + "级";
   //降水概率
   String pop = daily_forecast_first.getString("pop");
   //温度
   String tempText = temp.getString("min") + "℃~" + temp.getString("max") + "℃";
   //更新时间
   String updateTime = update.getString("loc");
   //城市名
   String cityName = basic.getString("city");
   saveWeatherInfo(context, cityName, sunriseTime, sunsetTime, dayWeather, nightWeather, windText, pop, tempText, updateTime);
  } catch (Exception e) {
   e.printStackTrace();
  }
 }

 private static void saveWeatherInfo(Context context, String cityName,
          String sunriseTime, String sunsetTime, String dayWeather, String nightWeather,
          String windText, String pop, String tempText, String updateTime) {
  SharedPreferences.Editor editor = context.getSharedPreferences("Weather", Context.MODE_PRIVATE).edit();
  editor.putString("cityName", cityName);
  editor.putString("sunriseTime", sunriseTime);
  editor.putString("sunsetTime", sunsetTime);
  editor.putString("dayWeather", dayWeather);
  editor.putString("nightWeather", nightWeather);
  editor.putString("wind", windText);
  editor.putString("pop", pop);
  editor.putString("temp", tempText);
  editor.putString("updateTime", updateTime);
  editor.commit();
 }
}

 六、适配器
由上边的动态图可以看到每小时的天气预测信息，那是使用ListView呈现的，这就要为其提供一个适配器了
ListView使用的布局文件如下：

<?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="horizontal">

 <!-- 时间 -->

 <TextView
  android:id="@+id/forecastTime"
  android:layout_width="0dp"
  android:layout_height="match_parent"
  android:layout_weight="2"
  android:gravity="center"
  android:textSize="20sp"
  android:textStyle="bold" />

 <LinearLayout
  android:layout_width="0dp"
  android:layout_height="match_parent"
  android:layout_weight="5"
  android:orientation="vertical">

  <!-- 温度 降水概率 -->

  <LinearLayout
   android:layout_width="match_parent"
   android:layout_height="0dp"
   android:layout_weight="1"
   android:gravity="center"
   android:orientation="horizontal">

   <!-- 温度 -->

   <TextView
    android:id="@+id/forecastTemp"
    android:layout_width="0dp"
    android:layout_height="match_parent"
    android:layout_weight="1"
    android:gravity="center" />

   <!-- 下雨概率 -->

   <TextView
    android:id="@+id/forecastPop"
    android:layout_width="0dp"
    android:layout_height="match_parent"
    android:layout_weight="1"
    android:gravity="center" />
  </LinearLayout>

  <!-- 风力 -->

  <TextView
   android:id="@+id/forecastWind"
   android:layout_width="match_parent"
   android:layout_height="0dp"
   android:layout_weight="1"
   android:gravity="center" />
 </LinearLayout>

</LinearLayout>

然后新建一个WeatherAdapter继承于ArrayAdapter< HourlyWeather>
只要重写getView(int position, View convertView, ViewGroup parent)方法即可

public class WeatherAdapter extends ArrayAdapter<HourlyWeather> {

 private int resourceId;

 private Context context;

 public WeatherAdapter(Context context, int textViewResourceId, List<HourlyWeather> objects) {
  super(context, textViewResourceId, objects);
  this.context = context;
  this.resourceId = textViewResourceId;
 }

 public View getView(int position, View convertView, ViewGroup parent) {
  HourlyWeather weather = getItem(position);
  View view = LayoutInflater.from(context).inflate(resourceId, null);

  TextView forecastTime = (TextView) view.findViewById(R.id.forecastTime);
  TextView forecastTemp = (TextView) view.findViewById(R.id.forecastTemp);
  TextView forecastPop = (TextView) view.findViewById(R.id.forecastPop);
  TextView forecastWind = (TextView) view.findViewById(R.id.forecastWind);

  forecastTime.setText(weather.getTime());
  forecastTemp.setText(weather.getTemp());
  forecastPop.setText(weather.getPop());
  forecastWind.setText(weather.getWind());
  return view;
 }

}

七、Activity的编写
首先要完成地区选择界面ChooseAreaActivity
ChooseAreaActivity的界面仅包括一个居中的TextView和一个ListView
布局文件如下：

<?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">

 <RelativeLayout
  android:layout_width="match_parent"
  android:layout_height="50dp">

  <TextView
   android:id="@+id/title"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:layout_centerInParent="true"
   android:textSize="24sp" />
 </RelativeLayout>

 <ListView
  android:id="@+id/listView"
  android:layout_width="match_parent"
  android:layout_height="match_parent" />

</LinearLayout>

ChooseAreaActivity 需要完成的操作有：完成地区列表的加载、将选择的County名传递给WeatherActivity
此外，当中使用了showProgressDialog()来呈现一个进度对话框，也设为无法通过返回键关闭，而我又没有在弱网环境下调试过，每次加载都是很快，也没见到对话框出来过，所以也不知道showProgressDialog()到底有没有bug啥的~

public class ChooseAreaActivity extends AppCompatActivity {

 // 标记当前列表为省份
 public static final int LEVEL_PROVINCE = 0;
 // 标记当前列表为城市
 public static final int LEVEL_CITY = 1;
 // 标记当前列表为县
 public static final int LEVEL_COUNTY = 2;
 // 进度对话框
 private ProgressDialog progressDialog;
 // 标题栏
 private TextView titleText;
 // 数据列表
 private ListView listView;
 // 列表数据
 private ArrayAdapter<String> adapter;
 // 数据库
 private WeatherDB weatherDB;

 private List<String> dataList;

 private List<Province> provinceList;

 private List<City> cityList;

 private List<County> countyList;
 //选择的省份
 private Province selectedProvince;
 //选择的城市
 private City selectedCity;
 //当前选择的列表类型
 private int currentLevel;
 //标记是否从WeatherActivity跳转而来的
 private boolean isFromWeatherActivity;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  isFromWeatherActivity = getIntent().getBooleanExtra("ChooseArea", false);
  SharedPreferences sharedPreferences = getSharedPreferences("Weather", Context.MODE_PRIVATE);

  // 如果country已选择且本Activity不是从天气界面启动而来的，则直接跳转到WeatherActivity

  if (!TextUtils.isEmpty(sharedPreferences.getString("CountyName", "")) && !isFromWeatherActivity) {
   Intent intent = new Intent(this, WeatherActivity.class);
   startActivity(intent);
   finish();
   return;
  }
  setContentView(R.layout.activity_choose_area);
  if (getSupportActionBar() != null) {
   getSupportActionBar().hide();
  }
  listView = (ListView) findViewById(R.id.listView);
  titleText = (TextView) findViewById(R.id.title);
  dataList = new ArrayList<>();
  adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, dataList);
  listView.setAdapter(adapter);
  weatherDB = WeatherDB.getInstance(this);
  listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
   @Override
   public void onItemClick(AdapterView<?> arg0, View arg1, int index, long arg3) {
    if (currentLevel == LEVEL_PROVINCE) {
     selectedProvince = provinceList.get(index);
     queryCities();
    } else if (currentLevel == LEVEL_CITY) {
     selectedCity = cityList.get(index);
     queryCounties();
    } else if (currentLevel == LEVEL_COUNTY) {
     //当点击到县列表时，就利用Intent跳转到天气信息界面
     String countyName = countyList.get(index).getCountyName();
     Intent intent = new Intent(ChooseAreaActivity.this, WeatherActivity.class);
     intent.putExtra("CountyName", countyName);
     startActivity(intent);
     finish();
    }
   }
  });
  queryProvinces();
 }

 private void queryProvinces() {
  showProgressDialog();
  provinceList = weatherDB.getAllProvince();
  if (provinceList.size() > 0) {
   dataList.clear();
   for (Province province : provinceList) {
    dataList.add(province.getProvinceName());
   }
   adapter.notifyDataSetChanged();
   listView.setSelection(0);
   titleText.setText("中国");
   currentLevel = LEVEL_PROVINCE;
   closeProgressDialog();
  } else {
   queryFromServer(null, "province");
  }
 }

 private void queryCities() {
  showProgressDialog();
  cityList = weatherDB.getAllCity(selectedProvince.getProvinceId());
  if (cityList.size() > 0) {
   dataList.clear();
   for (City city : cityList) {
    dataList.add(city.getCityName());
   }
   adapter.notifyDataSetChanged();
   listView.setSelection(0);
   titleText.setText(selectedProvince.getProvinceName());
   currentLevel = LEVEL_CITY;
   closeProgressDialog();
  } else {
   queryFromServer(selectedProvince.getProvinceId(), "city");
  }
 }

 private void queryCounties() {
  showProgressDialog();
  countyList = weatherDB.getAllCountry(selectedCity.getCityId());
  if (countyList.size() > 0) {
   dataList.clear();
   for (County county : countyList) {
    dataList.add(county.getCountyName());
   }
   adapter.notifyDataSetChanged();
   listView.setSelection(0);
   titleText.setText(selectedCity.getCityName());
   currentLevel = LEVEL_COUNTY;
   closeProgressDialog();
  } else {
   queryFromServer(selectedCity.getCityId(), "county");
  }
 }

 private void queryFromServer(final String code, final String type) {
  String address;
  // code不为空
  if (!TextUtils.isEmpty(code)) {
   address = "http://www.weather.com.cn/data/list3/city" + code + ".xml";
  } else {
   address = "http://www.weather.com.cn/data/list3/city.xml";
  }
  HttpUtil.sendHttpRequest(address, new HttpCallbackListener() {
   @Override
   public void onFinish(String response) {
    boolean result = false;
    if ("province".equals(type)) {
     result = Utility.saveProvincesResponse(weatherDB, response);
    } else if ("city".equals(type)) {
     result = Utility.saveCitiesResponse(weatherDB, response, selectedProvince.getProvinceId());
    } else if ("county".equals(type)) {
     result = Utility.saveCountiesResponse(weatherDB, response, selectedCity.getCityId());
    }
    if (result) {
     runOnUiThread(new Runnable() {
      @Override
      public void run() {
       if ("province".equals(type)) {
        queryProvinces();
       } else if ("city".equals(type)) {
        queryCities();
       } else if ("county".equals(type)) {
        queryCounties();
       }
      }
     });
    }
   }

   @Override
   public void onError(Exception e) {
    runOnUiThread(new Runnable() {
     @Override
     public void run() {
      Toast.makeText(ChooseAreaActivity.this, "加载失败", Toast.LENGTH_SHORT).show();
     }
    });
   }
  });
  closeProgressDialog();
 }

 private void showProgressDialog() {
  if (progressDialog == null) {
   progressDialog = new ProgressDialog(this);
   progressDialog.setMessage("正在加载……");
   progressDialog.setCanceledOnTouchOutside(false);
  }
  progressDialog.show();
 }

 private void closeProgressDialog() {
  if (progressDialog != null) {
   progressDialog.dismiss();
  }
 }

 @Override
 public void onBackPressed() {
  if (currentLevel == LEVEL_COUNTY) {
   queryCities();
  } else if (currentLevel == LEVEL_CITY) {
   queryProvinces();
  } else {
   if (isFromWeatherActivity) {
    Intent intent = new Intent(this, WeatherActivity.class);
    startActivity(intent);
   }
   finish();
  }
 }
}

WeatherActivity的布局相对复杂些，包含了许多个TextView，我也只是想着简单就好，就简单地把数据用文本呈现出来

// 城市切换按钮
 private Button citySwitch;
 // 刷新数据按钮
 private Button weatherRefresh;
 // 城市名
 private TextView cityName;
 // 白天夜晚天气描叙
 private TextView DayNightWeather;
 // 温度
 private TextView temp;
 // 日出时间
 private TextView sunriseTime;
 // 日落时间
 private TextView sunsetTime;
 // 风力
 private TextView wind;
 // 降水概率
 private TextView pop;
 // 发布时间
 private TextView updateTime;
 // 今日天气预测列表
 private ListView listview;

 public static List<HourlyWeather> weatherList = new ArrayList<>();

 private SharedPreferences sharedPreferences;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.weather);
  if (getSupportActionBar() != null) {
   getSupportActionBar().hide();
  }
  init();
 }

 private void init() {
  citySwitch = (Button) findViewById(R.id.citySwitch);
  weatherRefresh = (Button) findViewById(R.id.weatherRefresh);
  citySwitch.setOnClickListener(this);
  weatherRefresh.setOnClickListener(this);
  cityName = (TextView) findViewById(R.id.cityName);
  DayNightWeather = (TextView) findViewById(R.id.DayNightWeather);
  temp = (TextView) findViewById(R.id.temp);
  sunriseTime = (TextView) findViewById(R.id.sunriseTime);
  sunsetTime = (TextView) findViewById(R.id.sunsetTime);
  wind = (TextView) findViewById(R.id.wind);
  pop = (TextView) findViewById(R.id.pop);
  updateTime = (TextView) findViewById(R.id.updateTime);
  listview = (ListView) findViewById(R.id.hourlyForecast);
  sharedPreferences = getSharedPreferences("Weather", Context.MODE_PRIVATE);

  String countyName = getIntent().getStringExtra("CountyName");
  // 当countyName不为空
  if (!TextUtils.isEmpty(countyName)) {
   SharedPreferences.Editor editor = sharedPreferences.edit();
   editor.putString("CountyName", countyName);
   editor.commit();
  } else {
   countyName = sharedPreferences.getString("CountyName", "");
  }
  weatherRefresh.setText("同步中……");
  queryFromServer(countyName);
 }

 @Override
 public void onClick(View view) {
  switch (view.getId()) {
   case R.id.citySwitch:
    Intent intent = new Intent(this, ChooseAreaActivity.class);
    intent.putExtra("ChooseArea", true);
    startActivity(intent);
    finish();
    break;
   case R.id.weatherRefresh:
    weatherRefresh.setText("同步中……");
    String countyName = sharedPreferences.getString("CountyName", "");
    if (!TextUtils.isEmpty(countyName)) {
     queryFromServer(countyName);
    }
    break;
  }
 }

 private void queryFromServer(final String countyName) {
  try {
   String url = "http://apis.baidu.com/heweather/weather/free?city=";
   String name = new String(countyName.getBytes("UTF-8"), "iso-8859-1");
   HttpUtil.sendHttpRequest(url + name, new HttpCallbackListener() {
    @Override
    public void onFinish(String response) {
     Utility.handleWeatherResponse(WeatherActivity.this, response);
     runOnUiThread(new Runnable() {
      @Override
      public void run() {
       showWeather();
      }
     });
    }

    @Override
    public void onError(Exception e) {
     runOnUiThread(new Runnable() {
      @Override
      public void run() {
       Toast.makeText(WeatherActivity.this, "同步失败", Toast.LENGTH_LONG).show();
       weatherRefresh.setText("更新数据");
      }
     });
    }
   });
  } catch (Exception e) {
   e.printStackTrace();
  }

 }

 private void showWeather() {
  cityName.setText(sharedPreferences.getString("cityName", "未知"));
  sunriseTime.setText("日出：" + sharedPreferences.getString("sunriseTime", "未知"));
  sunsetTime.setText("日落：" + sharedPreferences.getString("sunsetTime", "未知"));
  DayNightWeather.setText("日：" + sharedPreferences.getString("dayWeather", "未知") + " 夜：" + sharedPreferences.getString("nightWeather", "未知"));
  temp.setText("温度：" + sharedPreferences.getString("temp", "未知"));
  wind.setText("风力：" + sharedPreferences.getString("wind", "未知"));
  pop.setText("降水概率：" + sharedPreferences.getString("pop", "未知"));
  updateTime.setText("发布时间:" + sharedPreferences.getString("updateTime", "未知"));
  WeatherAdapter adapter = new WeatherAdapter(this, R.layout.hourly_weather, weatherList);
  listview.setAdapter(adapter);
  Toast.makeText(WeatherActivity.this, "已经是最新数据了", Toast.LENGTH_SHORT).show();
  weatherRefresh.setText("更新数据");
 }

}

八、说明
很奇怪的是，这个小app在我的4.4版本的小米手机上运行无误，可在5.1系统的模拟器和华为手机上却提示无法获取到数据，返回的JSON数据提示说城市未知，查看了很久也没搞明白，只能作罢~~

代码下载地址：Android简易版天气预报app的实现（改进版）

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