进入实战，开发酷欧天气（三）
目标的坚定是性格中最必要的力量源泉之一，也是成功的利器之一。
本讲内容：遍历全国省市县数据
1、全国所有省市县的数据都是从服务器端获取到的，因此这里和服务器的交互不可少的，所以在util包下增加一个HttpUtil类，代码如下：
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);
InputStream in = connection.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(in));
StringBuilder response = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
response.append(line);
}
if (listener != null) {
// 回调onFinish()方法
listener.onFinish(response.toString());
}
} catch (Exception e) {
if (listener != null) {
// 回调onError()方法
listener.onError(e);
}
} finally {
if (connection != null) {
connection.disconnect();
}
}
}
}).start();
}
}HttpUtil类中使用到了HttpCallbackListener接口来回调服务器返回的结果，因此我们还需要添加这个接口，如下：
public interface HttpCallbackListener {
void onFinish(String response);
void onError(Exception e);
}
由于服务器返回的省市县数据都是“代号｜城市，代号｜城市”这种格式，所以我们最好再提供一个工具类来解析和处理这种数据。在util包下新建一个Utility类，代码如下:
public class Utility {
/**
* 解析和处理服务器返回的省级数据
*/
public synchronized static boolean handleProvincesResponse(
CoolWeatherDB coolWeatherDB, String response) {
if (!TextUtils.isEmpty(response)) {
String[] allProvinces = response.split(",");
if (allProvinces != null && allProvinces.length > 0) {
for (String p : allProvinces) {
String[] array = p.split("\\|");
Province province = new Province();
province.setProvinceCode(array[0]);
province.setProvinceName(array[1]);
// 将解析出来的数据存储到Province表
coolWeatherDB.saveProvince(province);
}
return true;
}
}
return false;
}
/**
* 解析和处理服务器返回的市级数据
*/
public static boolean handleCitiesResponse(CoolWeatherDB coolWeatherDB,
String response, int provinceId) {
if (!TextUtils.isEmpty(response)) {
String[] allCities = response.split(",");
if (allCities != null && allCities.length > 0) {
for (String c : allCities) {
String[] array = c.split("\\|");
City city = new City();
city.setCityCode(array[0]);
city.setCityName(array[1]);
city.setProvinceId(provinceId);
// 将解析出来的数据存储到City表
coolWeatherDB.saveCity(city);
}
return true;
}
}
return false;
}
/**
* 解析和处理服务器返回的县级数据
*/
public static boolean handleCountiesResponse(CoolWeatherDB coolWeatherDB,
String response, int cityId) {
if (!TextUtils.isEmpty(response)) {
String[] allCounties = response.split(",");
if (allCounties != null && allCounties.length > 0) {
for (String c : allCounties) {
String[] array = c.split("\\|");
County county = new County();
county.setCountyCode(array[0]);
county.setCountyName(array[1]);
county.setCityId(cityId);
// 将解析出来的数据存储到County表
coolWeatherDB.saveCounty(county);
}
return true;
}
}
return false;
}
/**
* 解析服务器返回的JSON数据，并将解析出的数据存储到本地。
*/
public static void handleWeatherResponse(Context context, String response) {
try {
JSONObject jsonObject = new JSONObject(response);
JSONObject weatherInfo = jsonObject.getJSONObject("weatherinfo");
String cityName = weatherInfo.getString("city");
String weatherCode = weatherInfo.getString("cityid");
String temp1 = weatherInfo.getString("temp1");
String temp2 = weatherInfo.getString("temp2");
String weatherDesp = weatherInfo.getString("weather");
String publishTime = weatherInfo.getString("ptime");
saveWeatherInfo(context, cityName, weatherCode, temp1, temp2,weatherDesp, publishTime);
} catch (JSONException e) {
e.printStackTrace();
}
}
/**
* 将服务器返回的所有天气信息存储到SharedPreferences文件中。
*/
public static void saveWeatherInfo(Context context, String cityName,
String weatherCode, String temp1, String temp2, String weatherDesp,String publishTime) {
SimpleDateFormat sdf = new SimpleDateFormat("yyyy年M月d日", Locale.CHINA);
SharedPreferences.Editor editor = PreferenceManager.getDefaultSharedPreferences(context).edit();
editor.putBoolean("city_selected", true);
editor.putString("city_name", cityName);
editor.putString("weather_code", weatherCode);
editor.putString("temp1", temp1);
editor.putString("temp2", temp2);
editor.putString("weather_desp", weatherDesp);
editor.putString("publish_time", publishTime);
editor.putString("current_date", sdf.format(new Date()));
editor.commit();
}
}提供了三个方法分别用于解析和处理服务器返回的省级、市级、县级数据。解析的规则就是先按逗号分隔，再按单竖线分隔，接着将解析出来的数据设置到实体类中，最后调用CoolWeatherDB中的三个save()方法将数据存储到相应的表中。
2、开始写界面
下面是res/layout/choose_area.xml布局文件
<?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"
android:background="#484E61" >
<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="24sp" />
</RelativeLayout>
<ListView
android:id="@+id/list_view"
android:layout_width="match_parent"
android:layout_height="match_parent" >
</ListView>
</LinearLayout>
下面是BaseActivity.java文件
/**
* 设置activity的基础类
* 变量可以在这里设置 (所有活动都可以继承)
*/
public class BaseActivity extends Activity {
public static final String TAG="tag";
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
/**
*用于所有活动测试
*/
public void toast(String msg){
Toast.makeText(this, msg, Toast.LENGTH_LONG).show();
Log.d(TAG, msg);
}
}
下面是ChooseAreaActivity.java文件
public class ChooseAreaActivity extends BaseActivity {
public static final int LEVEL_PROVINCE = 0;
public static final int LEVEL_CITY = 1;
public static final int LEVEL_COUNTY = 2;
private ProgressDialog progressDialog;
private TextView titleText;
private ListView listView;
private ArrayAdapter<String> adapter;
private CoolWeatherDB coolWeatherDB;
private List<String> dataList = new ArrayList<String>();
/**
* 省列表
*/
private List<Province> provinceList;
/**
* 市列表
*/
private List<City> cityList;
/**
* 县列表
*/
private List<County> countyList;
/**
* 选中的省份
*/
private Province selectedProvince;
/**
* 选中的城市
*/
private City selectedCity;
/**
* 当前选中的级别
*/
private int currentLevel;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.choose_area);
listView = (ListView) findViewById(R.id.list_view);
titleText = (TextView) findViewById(R.id.title_text);
adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, dataList);
listView.setAdapter(adapter);
coolWeatherDB = CoolWeatherDB.getInstance(this);
listView.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> arg0, View view, int index,long arg3) {
if (currentLevel == LEVEL_PROVINCE) {
selectedProvince = provinceList.get(index);
queryCities();
} else if (currentLevel == LEVEL_CITY) {
selectedCity = cityList.get(index);
queryCounties();
}
}
});
queryProvinces(); // 加载省级数据
}
/**
* 查询全国所有的省，优先从数据库查询，如果没有查询到再去服务器上查询。
*/
private void queryProvinces() {
provinceList = coolWeatherDB.loadProvinces();
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;
} else {
queryFromServer(null, "province");
}
}
/**
* 查询选中省内所有的市，优先从数据库查询，如果没有查询到再去服务器上查询。
*/
private void queryCities() {
cityList = coolWeatherDB.loadCities(selectedProvince.getId());
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;
} else {
queryFromServer(selectedProvince.getProvinceCode(), "city");
}
}
/**
* 查询选中市内所有的县，优先从数据库查询，如果没有查询到再去服务器上查询。
*/
private void queryCounties() {
countyList = coolWeatherDB.loadCounties(selectedCity.getId());
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;
} else {
queryFromServer(selectedCity.getCityCode(), "county");
}
}
/**
* 根据传入的代号和类型从服务器上查询省市县数据。
*/
private void queryFromServer(final String code, final String type) {
String address;
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";
}
showProgressDialog();
HttpUtil.sendHttpRequest(address, new HttpCallbackListener() {
public void onFinish(String response) {
boolean result = false;
if ("province".equals(type)) {
result = Utility.handleProvincesResponse(coolWeatherDB,response);
} else if ("city".equals(type)) {
result = Utility.handleCitiesResponse(coolWeatherDB, response, selectedProvince.getId());
} else if ("county".equals(type)) {
result = Utility.handleCountiesResponse(coolWeatherDB, response, selectedCity.getId());
}
if (result) {
// 通过runOnUiThread()方法回到主线程处理逻辑
runOnUiThread(new Runnable() {
public void run() {
closeProgressDialog();
if ("province".equals(type)) {
queryProvinces();
} else if ("city".equals(type)) {
queryCities();
} else if ("county".equals(type)) {
queryCounties();
}
}
});
}
}
public void onError(Exception e) {
// 通过runOnUiThread()方法回到主线程处理逻辑
runOnUiThread(new Runnable() {
public void run() {
closeProgressDialog();
toast("加载失败");
}
});
}
});
}
/**
* 显示进度对话框
*/
private void showProgressDialog() {
if (progressDialog == null) {
progressDialog = new ProgressDialog(this);
progressDialog.setMessage("正在加载...");
progressDialog.setCanceledOnTouchOutside(false);
}
progressDialog.show();
}
/**
* 关闭进度对话框
*/
private void closeProgressDialog() {
if (progressDialog != null) {
progressDialog.dismiss();
}
}
/**
* 捕获Back按键，根据当前的级别来判断，此时应该返回市列表、省列表、还是直接退出。
*/
public void onBackPressed() {
if (currentLevel == LEVEL_COUNTY) {
queryCities();
} else if (currentLevel == LEVEL_CITY) {
queryProvinces();
} else {
finish();
}
}
}
AndroidManifest.xml中的代码：
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.coolweather.app"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="21" />
<uses-permission android:name="android.permission.INTERNET" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="activity.ChooseAreaActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
git add .
git commit -m "完成遍历省市县三级列表的功能。"
git push origin master