Android 无法从共享首选项检索值
下面是UpdateWather的方法。我可以改变位置和温度单位。在更改位置时，参数会更改，但在更改单位时，不会更改任何内容，甚至在将位置用作字符串时显示的log.i在将位置更改为单位时也不会显示Android 无法从共享首选项检索值,android,Android,下面是UpdateWather的方法。我可以改变位置和温度单位。在更改位置时，参数会更改，但在更改单位时，不会更改任何内容，甚至在将位置用作字符串时显示的log.i在将位置更改为单位时也不会显示 private void updateWeather() { FetchWeatherTask weatherTask = new FetchWeatherTask(); SharedPreferences prefs = PreferenceManager.getDefault
private void updateWeather() {
FetchWeatherTask weatherTask = new FetchWeatherTask();
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getActivity());
String location = prefs.getString(getString(R.string.key), getString(R.string.default_value));
units = prefs.getString("listPref", "1");
Log.i("LOGGGGGGGGG",units);
weatherTask.execute(location,format,units);
}
private void updateWeather() {
FetchWeatherTask weatherTask = new FetchWeatherTask();
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getActivity());
String location = prefs.getString(getString(R.string.key), getString(R.string.default_value));
units = prefs.getString("listPref", "1");
Log.i("LOGGGGGGGGG",units);
weatherTask.execute(location,format,units);
}
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string-array name="listArray">
<item>Metric</item>
<item>Imperial</item>
</string-array>
<string-array name="listValues">
<item>1</item>
<item>2</item>
</string-array>
</resources>
米制的
帝国的
1.
2.
public class ForecastFragment extends Fragment {
private ArrayAdapter<String> mForecastAdapter;
String units;
String format = "json";
int numDays = 7;
public ForecastFragment() {
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Add this line in order for this fragment to handle menu events.
setHasOptionsMenu(true);
}
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
inflater.inflate(R.menu.forecastfragment, menu);
}
@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();
if (id == R.id.action_refresh) {
updateWeather();
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// The ArrayAdapter will take data from a source and
// use it to populate the ListView it's attached to.
mForecastAdapter =
new ArrayAdapter<String>(
getActivity(), // The current context (this activity)
R.layout.list_item_forecast, // The name of the layout ID.
R.id.list_item_forecast_textview, // The ID of the textview to populate.
new ArrayList<String>());
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
// Get a reference to the ListView, and attach this adapter to it.
ListView listView = (ListView) rootView.findViewById(R.id.list_view_forecast);
listView.setAdapter(mForecastAdapter);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int position, long l) {
String forecast = mForecastAdapter.getItem(position);
Intent intent = new Intent(getActivity(), MainActivity2Activity.class)
.putExtra(Intent.EXTRA_TEXT, forecast);
startActivity(intent);
}
});
return rootView;
}
private void updateWeather() {
FetchWeatherTask weatherTask = new FetchWeatherTask();
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getActivity());
String location = prefs.getString(getString(R.string.key), getString(R.string.default_value));
units = prefs.getString("listPref", "1");
Log.i("LOGGGGGGGGG", units);
weatherTask.execute(location, format, units);
}
@Override
public void onStart() {
super.onStart();
updateWeather();
}
public class FetchWeatherTask extends AsyncTask<String, Void, String[]> {
private final String LOG_TAG = FetchWeatherTask.class.getSimpleName();
/* The date/time conversion code is going to be moved outside the asynctask later,
* so for convenience we're breaking it out into its own method now.
*/
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);
}
/**
* 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.
* <p/>
* 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);
// OWM returns daily forecasts based upon the local time of the city that is being
// asked for, which means that we need to know the GMT offset to translate this data
// properly.
// Since this data is also sent in-order and the first day is always the
// current day, we're going to take advantage of that to get a nice
// normalized UTC date for all of our weather.
Time dayTime = new Time();
dayTime.setToNow();
// we start at the day returned by local time. Otherwise this is a mess.
int julianStartDay = Time.getJulianDay(System.currentTimeMillis(), dayTime.gmtoff);
// now we work exclusively in UTC
dayTime = new Time();
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);
// The date/time is returned as a long. We need to convert that
// into something human-readable, since most people won't read "1400356800" as
// "this saturday".
long dateTime;
// Cheating to convert this to UTC time, which is what we want anyhow
dateTime = dayTime.setJulianDay(julianStartDay + i);
day = getReadableDateString(dateTime);
// 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;
}
return resultStrs;
}
@Override
protected String[] doInBackground(String... params) {
// If there's no zip code, there's nothing to look up. Verify size of params.
if (params.length == 0) {
return null;
}
// These two need to be declared outside the try/catch
// so that they can be closed in the finally block.
HttpURLConnection urlConnection = null;
BufferedReader reader = null;
// Will contain the raw JSON response as a string.
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";
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))
.build();
URL url = new URL(builtUri.toString());
// 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(LOG_TAG, "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(LOG_TAG, "Error closing stream", e);
}
}
}
try {
return getWeatherDataFromJson(forecastJsonStr, numDays);
} catch (JSONException e) {
Log.e(LOG_TAG, e.getMessage(), e);
e.printStackTrace();
}
// This will only happen if there was an error getting or parsing the forecast.
return null;
}
@Override
protected void onPostExecute(String[] result) {
if (result != null) {
mForecastAdapter.clear();
for (String dayForecastStr : result) {
mForecastAdapter.add(dayForecastStr);
}
// New data is back from the server. Hooray!
}
}
}
公共类ForecastFragment扩展了片段{
专用阵列适配器mForecastAdapter；
弦单位；
String format=“json”；
int numDays=7；
公众预报员（）{
}
@凌驾
创建时的公共void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
//添加此行，以便此片段处理菜单事件。
设置选项菜单（真）；
}
@凌驾
创建选项菜单（菜单菜单，菜单充气机）{
充气机。充气（右菜单。艏楼碎片，菜单）；
}
@凌驾
公共布尔值onOptionsItemSelected（菜单项项）{
//处理操作栏项目单击此处。操作栏将
//自动处理Home/Up按钮上的点击，只要
//在AndroidManifest.xml中指定父活动时。
int id=item.getItemId（）；
if（id==R.id.action\u刷新）{
updatewather（）；
返回true；
}
返回super.onOptionsItemSelected（项目）；
}
@凌驾
创建视图上的公共视图（布局、充气机、视图组容器、，
Bundle savedInstanceState）{
//ArrayAdapter将从源获取数据并
//使用它填充它附加到的ListView。
mForecastAdapter=
新阵列适配器(
getActivity（），//当前上下文（此活动）
R.layout.list\u item\u forecast，//布局ID的名称。
R.id.list\u item\u forecast\u textview，//要填充的textview的id。
新的ArrayList（））；
视图根视图=充气机。充气（R.layout.fragment_main，容器，错误）；
//获取对ListView的引用，并将此适配器连接到它。
ListView ListView=（ListView）rootView.findViewById（R.id.list\u view\u forecast）；
setAdapter（mForecastAdapter）；
setOnItemClickListener（新的AdapterView.OnItemClickListener（）{
@凌驾
公共虚线单击（AdapterView AdapterView，视图视图，内部位置，长l）{
字符串forecast=mForecastAdapter.getItem（位置）；
意向意向=新意向（getActivity（），MainActivity2Activity.class）
.putExtra（Intent.EXTRA_文本，预测）；
星触觉（意向）；
}
});
返回rootView；
}
私有void updatewather（）{
FetchWeatherTask weatherTask=新的FetchWeatherTask（）；
SharedReferences prefs=PreferenceManager.GetDefaultSharedReferences（getActivity（））；
字符串位置=prefs.getString（getString（R.String.key）、getString（R.String.default_值））；
units=prefs.getString（“listPref”，“1”）；
Log.i（“loggggggg”，单位）；
weatherTask.execute（位置、格式、单位）；
}
@凌驾
public void onStart（）{
super.onStart（）；
updatewather（）；
}
公共类FetchWeatherTask扩展了AsyncTask{
私有最终字符串LOG_TAG=FetchWeatherTask.class.getSimpleName（）；
/*日期/时间转换代码稍后将被移到asynctask之外，
*为了方便起见，我们现在将其分解为自己的方法。
*/
私有字符串getReadableDateString（长时间）{
//因为API返回unix时间戳（以秒为单位），
//必须将其转换为毫秒才能转换为有效日期。
SimpleDateFormat shortenedDateFormat=新的SimpleDateFormat（“EEE MMM dd”）；
返回shortenedDateFormat.format（时间）；
}
/**
*为演示做好天气高/低的准备。
*/
专用字符串格式HighLows（双高、双低）{
//对于演示，假设用户不关心十分之一的学位。
长轮高=数学轮（高）；
长轮低=数学轮（低）；
字符串highLowStr=roundedHigh+“/”+roundedLow；
返回highLowStr；
}
/**
*以JSON格式获取表示完整预测的字符串，然后
*取出我们需要的数据来构造线框所需的字符串。
*
*幸运的是，解析很容易：构造函数获取JSON字符串并转换它
*为我们创建一个对象层次结构。
*/
私有字符串[]getWeatherDataFromJson（字符串forecastJsonStr，int numDays）
抛出JSONException{
//这些是需要提取的JSON对象的名称。
最终字符串OWM_LIST=“LIST”；
最终字符串OWM_WEATHER=“WEATHER”；
最终字符串OWM_TEMPERATURE=“temp”；
最终字符串OWM_MAX=“MAX”；
最终字符串OWM_MIN=“MIN”；
最终字符串OWM_DESCRIPTION=“main”；
JSONObject forecastJson=新的JSONObject（forecastJsonStr）；
JSONArray weatherArray=forecastJson.getJSONArray（OWM_列表）；
//OWM将根据所选城市的当地时间返回每日预测
//这意味着我们需要知道GMT偏移量来转换这些数据
//对。
//因为此数据也是按顺序发送的，并且第一天始终是
//今天，我们将利用这一点来获得一个好的
//我们所有天气的标准化UTC日期。
白天时间=新时间（）；
白天；
//我们从当地时间返回的那一天开始。否则这就是一片混乱。
int julianStartDay=Time.getJulianDay（System.currentTimeMillis（），day.gmtoff）；
//现在我们只在UTC工作
白天=新时间(