我正在使用OpenWeatherMap API开发天气预报应用程序，除非在用户尝试获取另一个城市的数据时刷新应用程序，否则一切顺利和好看，我已经测试了服务器调用并返回了真实数据，应该刷新的，但视图不会在片段中更新。
这是来自MainActivity类的片段：
public class MainActivity extends AppCompatActivity
implements
NavigationView.OnNavigationItemSelectedListener {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
session = new SessionManagement(MainActivity.this);
initComponents();
}
private void initComponents() {
//Initializes the components that the MainActivity layout has
city = getResources().getString(R.string.default_city);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
View navigationViewHeader = navigationView.getHeaderView(0);
mHeaderCityName = (TextView) navigationViewHeader.findViewById(R.id.tv_current_city);
mHeaderCityTemp = (TextView) navigationViewHeader.findViewById(R.id.tv_current_city_temp);
mFavCities = (ListView) navigationView.findViewById(R.id.lv_favorite_cities);
mTabs = (TabLayout) findViewById(R.id.tl_tabs);
mPages = (ViewPager) findViewById(R.id.vp_view_pager);
progressDialog = new ProgressDialog(MainActivity.this);
adapter = new MeteoPlusPagerAdapter(getSupportFragmentManager());
mTabs.setupWithViewPager(mPages);
savedCities = new ArrayList<>();
favoriteCities = new ArrayList<>();
citiesAdapter = new ArrayAdapter<>(this,
android.R.layout.simple_list_item_1, android.R.id.text1, favoriteCities);
mFavCities.setAdapter(citiesAdapter);
if (session.getFavorites() != null) {
savedCities = new ArrayList<>(session.getFavorites());
if (savedCities.size() > 0) {
favoriteCities.addAll(savedCities);
citiesAdapter.notifyDataSetChanged();
TextView mNoFavs = (TextView) navigationView.findViewById(R.id.tv_no_favorites);
mNoFavs.setVisibility(View.GONE);
mFavCities.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int position, long l) {
fetchWeatherData((String) adapterView.getAdapter().getItem(position));
}
});
}
}
if (citiesAdapter.getCount() == 0) {
TextView mNoFavs = (TextView) navigationView.findViewById(R.id.tv_no_favorites);
mNoFavs.setVisibility(View.VISIBLE);
mFavCities.setVisibility(View.GONE);
mFavCities.setEmptyView(navigationView.findViewById(R.id.tv_no_favorites));
}
}
/**
* Fetches data for weather preferences from server
*
* @param city
*/
void fetchWeatherData(final String city) {
final ApiInterface apiService = ApiClient.getClient().create(ApiInterface.class);
String appId = getResources().getString(R.string.openweathermap_appid);
Call<WeatherResponse> call = apiService.getCurrentWeatherDataSingleLocation(city, appId);
progressDialog.setMessage("Fetching data. Please wait...");
progressDialog.show();
call.enqueue(new Callback<WeatherResponse>() {
@Override
public void onResponse(Call<WeatherResponse> call, Response<WeatherResponse> response) {
progressDialog.dismiss();
weatherResponse = response.body();
mHeaderCityName.setText(city);
Log.d("city",weatherResponse.getCityName());//after refresh correct data returned
Log.d("cityId",Integer.toString(weatherResponse.getId()));//after refresh correct data returned
String identifier = isFahrenheit ? "°F" : "°C";
String temperature = String.format("%.0f " + identifier,
MeteoPlusUtility.convert(weatherResponse.getMain().getTemperature(), isFahrenheit));
mHeaderCityTemp.setText(temperature);
if (adapter.getCount() > 0) {
adapter.clear();
adapter.notifyDataSetChanged();
}
setupViewPager(mPages, weatherResponse);
//adapter.notifyDataSetChanged();
getSupportActionBar().setTitle(weatherResponse.getCityName());
}
@Override
public void onFailure(Call<WeatherResponse> call, Throwable t) {
progressDialog.dismiss();
call.cancel();
Toast.makeText(MainActivity.this, "Failed to obtain results!!", Toast.LENGTH_SHORT).show();
call.cancel();
// Log.e("API_CALL", t.getMessage());
}
});
}
/**
* @param viewPager the actual viewpager of the activity
*/
private void setupViewPager(ViewPager viewPager, WeatherResponse weatherResponse) {
//Sets up the whole view pager with all the pages in it
if (weatherResponse != null) {
String city = weatherResponse.getCityName();
String id = String.valueOf(weatherResponse.getId());
adapter.addFragment(NowFragment.newInstance(city), "Now");
adapter.addFragment(FiveDayThreeHourFragment.newInstance(id), "5 day/3 hour");
adapter.addFragment(DailyFragment.newInstance(id, "16"), "Daily");
viewPager.setAdapter(adapter);
} else {
Toast.makeText(MainActivity.this, "No data", Toast.LENGTH_SHORT).show();
}
}
private void displayAnotherCity() {
AlertDialog.Builder alertDialog = new AlertDialog.Builder(MainActivity.this);
alertDialog.setTitle("Select city");
alertDialog.setMessage("Please enter city");
final EditText input = new EditText(MainActivity.this);
LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.MATCH_PARENT,
LinearLayout.LayoutParams.MATCH_PARENT);
input.setLayoutParams(lp);
alertDialog.setView(input);
alertDialog.setIcon(R.mipmap.app_logo);
alertDialog.setPositiveButton("Confirm",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
fetchWeatherData(input.getText().toString());
adapter.notifyDataSetChanged();
dialog.dismiss();
}
});
alertDialog.setNegativeButton("Cancel",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
alertDialog.show();
}
这是NowFragment的一部分，所有片段在onActivityCreated方法中以相同的方式填充和获取数据。
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View mNow = LayoutInflater.from(getContext()).inflate(R.layout.tab_now, container, false);
initComponents(mNow);
return mNow;
}
/**
* fetches data from server and populates the view
*
* @param city
*/
void fetchWeatherData(String city) {
ApiInterface apiService = ApiClient.getClient().create(ApiInterface.class);
String appId = getResources().getString(R.string.openweathermap_appid);
Call<WeatherResponse> call = apiService.getCurrentWeatherDataSingleLocation(city, appId);
call.enqueue(new Callback<WeatherResponse>() {
@Override
public void onResponse(Call<WeatherResponse> call, Response<WeatherResponse> response) {
progressDialog.dismiss();
weatherData = response.body();
prepareData(weatherData);
}
@Override
public void onFailure(Call<WeatherResponse> call, Throwable t) {
call.cancel();
Toast.makeText(getContext(), "Failed to obtain results!!", Toast.LENGTH_SHORT).show();
Log.e("API_CALL", t.getMessage());
}
});
}
/**
* Intitializes the elements of the view
*
* @param view the view to display
*/
private void initComponents(View view) {
city = getArguments().getString(MeteoPlusUtility.TAG_CURRENT_WEATHER);
mCurrenTime = (TextView) view.findViewById(R.id.tv_current_time);
mWeatherTemperature = (TextView) view.findViewById(R.id.tv_weather_temperature);
mWeatherMain = (TextView) view.findViewById(R.id.tv_weather_main);
mWeatherDescription = (TextView) view.findViewById(R.id.tv_weather_description);
mWeatherHumidity = (TextView) view.findViewById(R.id.tv_weather_humidity);
mWeatherWindSpeed = (TextView) view.findViewById(R.id.tv_weather_wind_speed);
mWeatherPressure = (TextView) view.findViewById(R.id.tv_weather_pressure);
mWeatherHighTemp = (TextView) view.findViewById(R.id.tv_weather_high_temp);
mWeatherLowTemp = (TextView) view.findViewById(R.id.tv_weather_low_temp);
mWeatherSunrise = (TextView) view.findViewById(R.id.tv_weather_sunrise);
mWeatherSunset = (TextView) view.findViewById(R.id.tv_weather_sunset);
mWeatherDataCalculation = (TextView) view.findViewById(R.id.tv_weather_dt);
mWeatherIcon = (ImageView) view.findViewById(R.id.iv_weather_icon);
progressDialog = new ProgressDialog(getContext());
}
@Override
public void onResume() {
super.onResume();
refreshData();
}
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
refreshData();
}
/**
* prepares all the data fetched from server to the corresponding elements in the layout
*
* @param wData response from server
*/
private void prepareData(WeatherResponse wData) {
if (wData != null) {
MainWeatherData mainWeatherData = wData.getMain();
List<Weather> wList = wData.getWeatherList();
Weather generalWeatherData = wList.get(0);
Wind wind = wData.getWind();
WeatherSystem sys = wData.getSys();
String identifier = isFahrenheit ? "°F" : "°C";
Uri uri = Uri.parse(MeteoPlusUtility.OPENWEATHER_ICON_URL + generalWeatherData.getIconId() + ".png");
Picasso.with(getContext()).load(uri).resize(300, 300).centerInside().into(mWeatherIcon);
mCurrenTime.setText(MeteoPlusUtility.currentDateToString());
String temperature = String.format("%.0f " + identifier, MeteoPlusUtility.convert(mainWeatherData.getTemperature(), isFahrenheit));
mWeatherTemperature.setText(temperature);
mWeatherMain.setText(generalWeatherData.getMain());
mWeatherDescription.setText(generalWeatherData.getDescription());
String humidity = String.valueOf(mainWeatherData.getHumidity()) + " %";
mWeatherHumidity.setText(humidity);
String windSpeed = String.valueOf(wind.getSpeed()) + " KPH";
mWeatherWindSpeed.setText(windSpeed);
String pressure = String.valueOf(mainWeatherData.getPressure()) + " hPa";
mWeatherPressure.setText(pressure);
String lowTemp = String.format("%.0f " + identifier, MeteoPlusUtility.convert(mainWeatherData.getTempMin(), isFahrenheit));
mWeatherLowTemp.setText(lowTemp);
String highTemp = String.format("%.0f " + identifier, MeteoPlusUtility.convert(mainWeatherData.getTempMax(), isFahrenheit));
mWeatherHighTemp.setText(highTemp);
mWeatherSunrise.setText(MeteoPlusUtility.getTimeInPreetyFormat(sys.getSunrise(),
new SimpleDateFormat("HH:mm zzz")));
mWeatherSunset.setText(MeteoPlusUtility.getTimeInPreetyFormat(sys.getSunset(),
new SimpleDateFormat("HH:mm zzz")));
mWeatherDataCalculation.setText(MeteoPlusUtility.getTimeInPreetyFormat(wData.getTimeofDataCalculation(), new SimpleDateFormat("HH:mm zzz")));
}
}
/**
* creates instance of the fragment
*
* @param city used for data fetch
* @return fragment
*/
public static NowFragment newInstance(String city) {
NowFragment nowFragment = new NowFragment();
Bundle args = new Bundle();
args.putString(MeteoPlusUtility.TAG_CURRENT_WEATHER, city);
nowFragment.setArguments(args);
return nowFragment;
}
@Override
public void setArguments(Bundle args) {
super.setArguments(args);
}
@Override
public void refreshData() {
fetchWeatherData(city);
}
这是ViewPagerAdapter代码：
public class MeteoPlusPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragments = new ArrayList<>();
private final List<String> mFragmentsTitles = new ArrayList<>();
public MeteoPlusPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
return mFragments.get(position);
}
@Override
public int getCount() {
return mFragments.size();
}
/**
* adds fragment and title for the fragment to the corresponding lists
*
* @param fragment Fragment to be added
* @param title title of the added fragment
*/
public void addFragment(Fragment fragment, String title) {
//Adds fragment to the view pager with title to be displayed in the tab layout
mFragments.add(fragment);
mFragmentsTitles.add(title);
}
public void clear(){
mFragments.clear();
mFragmentsTitles.clear();
}
@Override
public int getItemPosition(Object object) {
// if (object instanceof NowFragment) {
// ((NowFragment) object).refreshData();
// } else if (object instanceof FiveDayThreeHourFragment) {
// ((FiveDayThreeHourFragment) object).refreshData();
// } else if (object instanceof DailyFragment) {
// ((DailyFragment) object).refreshData();
// }
// return super.getItemPosition(object);
return POSITION_NONE;
}
@Override
public CharSequence getPageTitle(int position) {
return mFragmentsTitles.get(position);
}
我真的很生气，无法找到问题的原因，我在详细调试和检查，搜索解决方案但没有结果，请帮忙。
答案 0 :(得分：0)
return POSITION_NONE;
你必须为你的适配器调用notifyDataSetChanged