【发布时间】：2023-02-07 14:42:35
【问题描述】：
在这里，流程首先在屏幕中有三个按钮，它们也是使用回收器视图创建的。视图模型正在传递数据以填充按钮内容，即图像和文本。这工作正常。点击按钮，一个新的屏幕/片段加载，应该显示列表。使用以下方法获取 API 数据：
public class TrackRepository {
MutableLiveData<TrackData> trackData;
RestClient restClient;
SharedPreferences sharedPreferences;
public TrackRepository() {
trackData = new MutableLiveData<>();
this.restClient = new RestClient();
sharedPreferences = SessionManager.getPreferences();
}
public void getTrackList(String startDate,String endDate,String searchTest){
int centerId = ClientInfo.getCenterId(sharedPreferences);
String auth = ClientInfo.getAuthToken(sharedPreferences);
JsonObject jsonObject = new JsonObject();
jsonObject.addProperty("CenterId",centerId);
jsonObject.addProperty("SearchText",searchTest);
jsonObject.addProperty("StartDate",startDate);
jsonObject.addProperty("EndDate",endDate);
restClient.getEndpoints().getTrackReports(auth,jsonObject).enqueue(new Callback<TrackData>() {
@Override
public void onResponse(Call<TrackData> call, Response<TrackData> response) {
if (response.isSuccessful()){
boolean success = response.body().isSuccess();
String message = response.body().getMessage();
try {
if (success) {
trackData.postValue(response.body());
}else {
trackData.postValue(response.body());
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
@Override
public void onFailure(Call<TrackData> call, Throwable t) {
trackData.postValue(null);
}
});
}
public LiveData<TrackData> getTrackDataMutableLiveData() {
return trackData;
}
}
在此之后，追踪HomeViewModel创建后由片段 TrackHome 和 TrackScreen 使用，如下所示
public class TrackHomeViewModel extends ViewModel {
ArrayList<String> btName;//button text
ArrayList<Integer> btImage; //button image
int FLAG;
SimpleDateFormat inFormat;
private TrackRepository trackRepository;
List<TrackData> trackList;
LiveData<TrackData> track;
public TrackHomeViewModel() {
btName = new ArrayList<>();
this.btName.add("Previous Day");
this.btName.add("Previous Three Days");
btImage = new ArrayList<>();
this.btImage.add(R.drawable.ic_baseline_calendar_today_24);
this.btImage.add(R.drawable.ic_baseline_calendar_view_day_24);
trackRepository = new TrackRepository();
track = trackRepository.getTrackDataMutableLiveData();
}
public void captureCardClick(int adapterPosition) {
String selectedChoice;
String searchTest,startDate,endDate;
SimpleDateFormat dateFormatter = new SimpleDateFormat("yyyy-MM-dd", Locale.US);
inFormat = new SimpleDateFormat("HH:mm:ss", Locale.US);
Calendar cal = Calendar.getInstance();
selectedChoice = btName.get(adapterPosition);
if (selectedChoice.equals("Previous Day")) {
FLAG = 1;
searchTest = "";
endDate = dateFormatter.format(cal.getTime()); // get current date
cal.add(Calendar.DATE, -1); //ONE day before of current date
startDate = dateFormatter.format(cal.getTime()); // get PREVIOUS date
// int centerId = ClientInfo.getCenterId(preferences);
getTrackList(startDate,endDate,searchTest);
}else if(selectedChoice.equals("Previous Three Days")){
FLAG = 2;
searchTest = "";
endDate = dateFormatter.format(cal.getTime()); // get current date
cal.add(Calendar.DATE, -3); //Three day before of current date
startDate = dateFormatter.format(cal.getTime()); // get PREVIOUS date
// int centerId = ClientInfo.getCenterId(preferences);
getTrackList(startDate,endDate,searchTest);
}
}
public void getTrackList(String startDate,String endDate,String searchTest) {
trackRepository.getTrackList(startDate, endDate, searchTest);
}
public LiveData<TrackData> getTrackLiveData() {
return track;
}
}
在里面轨迹屏片段，像下面这样加载 RecyclerView：
public class TrackScreen extends Fragment {
private TrackHomeViewModel trackHomeViewModel;
RecyclerView recyclerView;
TrackAdapter trackAdapter;
LinearLayoutManager linearLayoutManager;
Fragment trackHome;
SearchView searchView;
List<TrackData> trackDataList;
TextView currentFragment;
MaterialToolbar toolbar;
ImageButton back;
TrackInterface trackInterface;
TrackData trackD;
public static TrackScreen newInstance() {
return new TrackScreen();
}
@Override
public void onCreate(@Nullable Bundle saveInstanceState) {
super.onCreate(saveInstanceState);
trackHomeViewModel = new ViewModelProvider(this).get(TrackHomeViewModel.class);
trackHomeViewModel.getTrackLiveData().observe(this, new Observer<TrackData>() {
@Override
public void onChanged(TrackData trackData) {
trackD = trackData;
}
});
trackInterface = new TrackInterface() {
@Override
public void captureRowClick(TrackData trackData, int adapterPosition) {
String patId = trackData.getPatientId();
Toast.makeText(getContext(), "Patient ID is " + patId, Toast.LENGTH_SHORT).show();
}
};
}
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container,
@Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_track_screen,container,false);
toolbar = view.findViewById(R.id.toolbar);
searchView = view.findViewById(R.id.search_report);
recyclerView = view.findViewById(R.id.track_recycler);
currentFragment = view.findViewById(R.id.current_fragment);
currentFragment.setText("Reports");
back = view.findViewById(R.id.back_screen);
trackHome = getParentFragmentManager().findFragmentByTag("TrackHome");
linearLayoutManager = new LinearLayoutManager(getContext());
recyclerView.setLayoutManager(linearLayoutManager);
if(trackAdapter==null) {
trackHomeViewModel.getTrackLiveData().observe(getViewLifecycleOwner(), new Observer<TrackData>() {
@Override
public void onChanged(TrackData trackData) {
trackAdapter = new TrackAdapter(getContext(),trackData.getTrackData(),trackInterface);
}
});
recyclerView.setAdapter(trackAdapter);
}else{
Toast.makeText(getContext(), "No Data Found", Toast.LENGTH_SHORT).show();
}
// other code
}
}
数据从 API 加载，但 TrackScreen 显示空白屏幕E/RecyclerView：没有连接适配器；跳过布局消息，我测试了所有其他东西仍然是相同的消息。问题是当 TrackScreen 片段加载时列表为空，并且在执行 getTrackLiveData() 方法后加载 API 数据，因此加载列表为空，因此出现此消息。我不知道如何解决这个问题。
单击按钮时，它应该加载带有列表的 TrackScreen 片段。试过如上。
【问题讨论】：
标签： android android-recyclerview android-adapter android-viewmodel