并且仍然無法讓我的適配器從新數(shù)據(jù)集中進(jìn)行更新。我在調(diào)試模式下的代碼如下：public class PetInformationActivity extends AppCompatActivityimplements ConfirmDialogFragment.ConfirmDialogListener, MedicalInformationFragment.OnFragmentInteractionListener{private static List<Assignment> listAssignments = new ArrayList<>();private static AssignmentsAdapter mAdapter;private static PetInformationViewModel sPetInformationViewModel;...protected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);.../*** get the providers' IDs assigned to the pet: fillAssignmentsArray()*/listAssignments = sPetInformationViewModel.getAssignedProviders(petId);此時調(diào)試中：mAdapter = nulllistAssignments = (ArrayList@5411) size = 0Log.d(TAG, "listAssignments has " + listAssignments.size() + " Assignment objects in it"); Log.d(TAG, "listAssignments is: " + listAssignments); 此時調(diào)試中：mAdapter = nulllistAssignments = (ArrayList@5461) size = 10 = (Assignment@5496)"Assignment{mType='Veterinarian', mProviderName='red vet'}"mAdapter = new AssignmentsAdapter(this, listAssignments); 此時調(diào)試中：mAdapter = (AssignmentsAdapter@5499)listAssignments = (ArrayList@5461) size = 10 = (Assignment@5496)"Assignment{mType='Veterinarian', mProviderName='red vet'}"mRecyclerView.setAdapter(mAdapter);...}public void onResume(){super.onResume();Log.d(TAG, "Entered: onResume");listAssignments.clear();Log.d(TAG, "listAssignments is: " + listAssignments);此時屏幕是空白的，它應(yīng)該顯示在 Assignment@5607 中顯示的文本。似乎 notififyDataSetChanged() 通知 mAdapter 將 onCreate (ArrayList@5461) 中顯示的文本更改為清除 onResume (ArrayList@5461)，但沒有通知 onResume (ArrayList@5594) 中對數(shù)據(jù)的新調(diào)用。這似乎表明當(dāng) mAdapter 初始化為 listAssignments 時，它被設(shè)置為使用地址 @5461 的 ArrayList。當(dāng)在 onResume 中調(diào)用新數(shù)據(jù)時，在 a) 使用后退按鈕返回和 (b) 當(dāng)此 Activity 首次啟動時，會在不同的地址創(chuàng)建一個新的 ArrayList。因此，我似乎沒有正確地合并我的 ArrayList，因為對 listAssignments 的所有更新都會產(chǎn)生一個全新的 ArrayList 對象，該對象永遠(yuǎn)不會用于更新 mAdapter，它將始終更新為地址 @5461 處的初始 ArrayList。我已經(jīng)搜索了有關(guān)如何正確地將適配器綁定到 ArrayList 的信息，但我沒有找到任何暗示比我所做的更多的信息。我假設(shè) notifyDataSetChanged() 的目的是使用現(xiàn)有的適配器進(jìn)行更新，這樣現(xiàn)有的適配器就不必被銷毀，并且在每個數(shù)據(jù)集更改時創(chuàng)建一個新的適配器
由于 ArrayList 到適配器綁定問題，notifyDataSetChanged()
慕田峪7331174
2022-05-12 17:22:35
