ForecastFragment.java
// Created by vgangwar7 on 31/05/16.
public class ForecastFragment extends Fragment {
public final class BuildConfig {
public static final String OPEN_WEATHER_MAP_API_KEY = "1912b14c788b31e4f1ae441a0ceefb18";
}
private ArrayAdapter<String> forecastAdapter;
public ForecastFragment(){}
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
// Add this line in order for this fragment to handle menu events
setHasOptionsMenu(true);
updateWeather();
}
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
// Inflate the menu; this adds items to the action bar if it is present.
inflater.inflate(R.menu.forecastfragment, menu);
}
public boolean onOptionsItemSelected(MenuItem menuItem) {
int id = menuItem.getItemId();
if (id == R.id.action_refresh) {
FetchWeatherTask weatherTask = new FetchWeatherTask();
weatherTask.execute("110085");
return true;
}
return super.onOptionsItemSelected(menuItem);
}
private void updateWeather() {
FetchWeatherTask weatherTask = new FetchWeatherTask();
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(getActivity());
String location = preferences.getString(getString(R.string.pref_location_key),
getString(R.string.pref_location_default));
weatherTask.execute(location);
}
public void onStart() {
super.onStart();
updateWeather();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
String[] forecastArray =
{"Today - Sunny - 88/63",
"Tomorrow - Foggy - 70/40",
"Weds - Cloudy - 72/63",
"Thurs - Asteroids - 75/65",
"Fri - Heavy Rain - 65/56",
"Sat - HELP TRAPPED IN WEATHERSITUATION - 65/51",
"Sun - Sunny - 88/68"};
List<String> weekForecast = new ArrayList<String>(Arrays.asList(forecastArray));
forecastAdapter = new ArrayAdapter<>(getActivity(),R.layout.list_item_forecast, R.id.list_item_forecast_textview, weekForecast);
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
ListView listView = (ListView) rootView.findViewById(R.id.listview_forecast);
listView.setAdapter(forecastAdapter);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
Toast.makeText(getActivity(), forecastAdapter.getItem(position), Toast.LENGTH_SHORT).show();
}
});
return rootView;
}
public class FetchWeatherTask extends AsyncTask<String, Void, String[]> {
private final String TAG = FetchWeatherTask.class.getSimpleName();
String format = "json";
String units = "metric";
final int numDays = 7;
private String getReadableDateString(long time) {
// Because the API returns a unix timestamp (measured in seconds),
// it must be converted to milliseconds in order to be converted to valid date.
SimpleDateFormat shortenedDateFormat = new SimpleDateFormat("EEE MMM dd");
return shortenedDateFormat.format(time);
}
/**
* Take the String representing the complete forecast in JSON Format and
* pull out the data we need to construct the Strings needed for the wireframes.
*
* Fortunately parsing is easy: constructor takes the JSON string and converts it
* into an Object hierarchy for us.
*/
//Prepare the weather high/lows for presentation.
private String formatHighLows(double high, double low) {
// For presentation, assume the user doesn't care about tenths of a degree.
long roundedHigh = Math.round(high);
long roundedLow = Math.round(low);
String highLowStr = roundedHigh + "/" + roundedLow;
return highLowStr;
}
/**
* Take the String representing the complete forecast in JSON Format and
* pull out the data we need to construct the Strings needed for the wireframes.
*
* Fortunately parsing is easy: constructor takes the JSON string and converts it
* into an Object hierarchy for us.
*/
private String[] getWeatherDataFromJson(String forecastJsonStr, int numDays)
throws JSONException {
// These are the names of the JSON objects that need to be extracted.
final String OWM_LIST = "list";
final String OWM_WEATHER = "weather";
final String OWM_TEMPERATURE = "temp";
final String OWM_MAX = "max";
final String OWM_MIN = "min";
final String OWM_DESCRIPTION = "main";
JSONObject forecastJson = new JSONObject(forecastJsonStr);
JSONArray weatherArray = forecastJson.getJSONArray(OWM_LIST);
String[] resultStrs = new String[numDays];
for(int i = 0; i < weatherArray.length(); i++) {
// For now, using the format "Day, description, hi/low"
String day;
String description;
String highAndLow;
// Get the JSON object representing the day
JSONObject dayForecast = weatherArray.getJSONObject(i);
//create a Gregorian Calendar, which is in current date
GregorianCalendar gc = new GregorianCalendar();
//add i dates to current date of calendar
gc.add(GregorianCalendar.DATE, i);
//get that date, format it, and "save" it on variable day
Date time = gc.getTime();
SimpleDateFormat shortenedDateFormat = new SimpleDateFormat("EEE MMM dd");
day = shortenedDateFormat.format(time);
// description is in a child array called "weather", which is 1 element long.
JSONObject weatherObject = dayForecast.getJSONArray(OWM_WEATHER).getJSONObject(0);
description = weatherObject.getString(OWM_DESCRIPTION);
// Temperatures are in a child object called "temp". Try not to name variables
// "temp" when working with temperature. It confuses everybody.
JSONObject temperatureObject = dayForecast.getJSONObject(OWM_TEMPERATURE);
double high = temperatureObject.getDouble(OWM_MAX);
double low = temperatureObject.getDouble(OWM_MIN);
highAndLow = formatHighLows(high, low);
resultStrs[i] = day + " - " + description + " - " + highAndLow;
}
for (String s : resultStrs) {
Log.v("FetchWeatherTask", "Forecast entry: " + s);
}
return resultStrs;
}
@Override
protected String[] doInBackground(String... params) {
if (params.length == 0) {
return null;
}
//These two needed to be declared outside try catch block
HttpURLConnection urlConnection = null;
BufferedReader reader = null;
String forecastJsonStr = null;
try {
// Construct the URL for the OpenWeatherMap query
// Possible parameters are avaiable at OWM's forecast API page, at
// http://openweathermap.org/API#forecast
final String FORECAST_BASE_URL = "http://api.openweathermap.org/data/2.5/forecast/daily?";
final String QUERY_PARAM = "q";
final String FORMAT_PARAM = "mode";
final String UNITS_PARAM = "units";
final String DAYS_PARAM = "cnt";
final String APPID_PARAM = "APPID";
Uri builtUri = Uri.parse(FORECAST_BASE_URL).buildUpon()
.appendQueryParameter(QUERY_PARAM, params[0])
.appendQueryParameter(FORMAT_PARAM, format)
.appendQueryParameter(UNITS_PARAM, units)
.appendQueryParameter(DAYS_PARAM, Integer.toString(numDays))
.appendQueryParameter(APPID_PARAM, BuildConfig.OPEN_WEATHER_MAP_API_KEY)
.build();
URL url = new URL(builtUri.toString());
Log.v(TAG, "Built URI " + builtUri.toString());
// Create the request to OpenWeatherMap, and open the connection
urlConnection = (HttpURLConnection) url.openConnection();
// Create the request to OpenWeatherMap, and open the connection
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.connect();
// Read the input stream into a String
InputStream inputStream = urlConnection.getInputStream();
StringBuffer buffer = new StringBuffer();
if (inputStream == null) {
// Nothing to do.
return null;
}
reader = new BufferedReader(new InputStreamReader(inputStream));
String line;
while ((line = reader.readLine()) != null) {
// Since it's JSON, adding a newline isn't necessary (it won't affect parsing)
// But it does make debugging a *lot* easier if you print out the completed
// buffer for debugging.
buffer.append(line + "\n");
}
if (buffer.length() == 0) {
// Stream was empty. No point in parsing.
return null;
}
forecastJsonStr = buffer.toString();
} catch (IOException e) {
Log.e("ForecastFragment", "Error ", e);
// If the code didn't successfully get the weather data, there's no point in attemping
// to parse it.
return null;
} finally
{
if (urlConnection != null) {
urlConnection.disconnect();
}
if (reader != null) {
try {
reader.close();
} catch (final IOException e) {
Log.e("ForecastFragment", "Error closing stream", e);
}
}
}
try{
getWeatherDataFromJson(forecastJsonStr, numDays);
}catch (JSONException e){
Log.e(TAG ,e.getMessage(), e);
e.printStackTrace();
}
return null;
}
@Override
public void onPostExecute(String[] result) {
if (result != null) {
forecastAdapter.clear();
for (String dayForecastStr : result) {
forecastAdapter.addAll(dayForecastStr);
}
forecastAdapter.notifyDataSetChanged();
}
}
}
}
MainActivity.java
public class MainActivity extends AppCompatActivity
{
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction().add(R.id.container, new ForecastFragment()).commit();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
if (id == R.id.action_refresh) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
尽管如此，在我的logcat中，我能够看到API中提取的数据，并且代码中没有任何错误。 LogCat -
06-04 16：11：31.432 3730-3769 / com.example.vgangwar7.sunshine V / FetchWeatherTask：预测参赛作品：Sun Jun 05 - Clear - 43/31 06-04 16：11：31.432 3730-3769 / com.example.vgangwar7.sunshine V / FetchWeatherTask：预测参赛作品：星期一六月06 - 晴 - 40/26 06-04 16：11：31.432 3730-3769 / com.example.vgangwar7.sunshine V / FetchWeatherTask：预测参赛作品：Tue Jun 07 - Clear - 39/28 06-04 16：11：31.432 3730-3769 / com.example.vgangwar7.sunshine V / FetchWeatherTask：预测参赛作品：2008年6月3日星期三 - 晴 - 39/26 06-04 16：11：31.432 3730-3769 / com.example.vgangwar7.sunshine V / FetchWeatherTask：预测参赛作品：Thu Jun 09 - 晴 - 41/27 06-04 16：11：31.432 3730-3769 / com.example.vgangwar7.sunshine V / FetchWeatherTask：预测参赛作品：6月10日星期五 - 雨 - 39/26
答案 0 :(得分：0)
尝试覆盖onStart方法：
while(file_exists("looper"))
{
//your code here
}
问候。
答案 1 :(得分：0)
执行异步任务时，需要确保在使用任务重新生成的结果之前完成任务。在您的情况下，选择刷新时，您正在使用weatherTask.execute("110085");执行任务。让我们说完成任务需要3秒钟并返回结果。但是下一行中的return语句将立即执行，强制布局重新加载（假设这里需要1秒才能重新加载）。这里发生的是当您执行异步任务时，将创建另一个进程以获取数据并立即继续执行原始执行，而无需等待异步任务完成。即，执行会立即移至下一行而无需等待任务的结果。在您的情况下，重新加载是在您的任务实际提取数据之前完成的。例如，您的屏幕在输入optionSelected方法的第一秒加载，但仅在2秒之后，您将从异步任务获取天气数据。因此更新的数据显示在logcat中，但不在屏幕中，因为活动在加载时没有收到数据。因此，您需要确保仅在收到数据后才加载布局。你可以通过在你的执行上调用get（）来做到这一点。
在onOptionsItemSelected的方法ForecastFragment中，更改
weatherTask.execute("110085");
到
weatherTask.execute("110085").get();
这应该为你带来魔力。
答案 2 :(得分：0)
我不确定你什么时候想要刷新＆＃34;数据以及你是如何做到的，你能解释一下更新数据而不是复制所有代码的策略吗？ 通常步骤是：
我想你已经了解了Android中的活动状态。如果你没有，那就去做吧。然后，您可以根据需要使用onStart或onResume。
答案 3 :(得分：0)
在updateWeather();方法
OnOptionsItemSelected()函数
public boolean onOptionsItemSelected(MenuItem menuItem) {
int id = menuItem.getItemId();
if (id == R.id.action_refresh) {
//FetchWeatherTask weatherTask = new FetchWeatherTask();
//weatherTask.execute("110085");
updateWeather();
return true;
}
return super.onOptionsItemSelected(menuItem);
}
当你从forecastJsonStr制作天气预报字符串时，在doInBackground添加一个返回语句
@Override
protected String[] doInBackground(String... params) {
.//your code
.//your code
.//your code
.
.
try{
return getWeatherDataFromJson(forecastJsonStr, numDays);//add return here!!
}catch (JSONException e){
Log.e(TAG ,e.getMessage(), e);
e.printStackTrace();
}
return null;
}