【发布时间】：2021-01-05 05:44:43
【问题描述】：
在我的代码中，我正在通过方法setUpRecyclerView(country); 构建一个回收器视图，当我快速创建我的片段时，稍后我调用相同的方法（或构建回收器视图的各种其他方法，例如setUpRecyclerViewWithKeyword(country, search_key); ， setUpRecyclerViewWithPreferences(country, anime, art, edu, gaming, music, other); , setUpRecyclerViewWithKeywordAndPreferences(country, search_key, anime, art, edu, gaming, music, other); ) 再次构建回收站视图。如下图所示：
我的 Fragments OnViewCreated 代码
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
final String id = FirebaseAuth.getInstance().getCurrentUser().getUid();
search_keyword = getView().findViewById(R.id.exp_search);
search_btn = getView().findViewById(R.id.exp_search_btn);
ccp = getView().findViewById(R.id.exp_ccp);
refresh = getView().findViewById(R.id.refresh);
country = ccp.getSelectedCountryName();
setUpRecyclerView(country);
Log.e("explore frag","1");
db.collection("Users").document(id).collection("preferences").document("event").get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
@Override
public void onComplete(@NonNull Task<DocumentSnapshot> task) {
if (task.isSuccessful()) {
DocumentSnapshot documentSnapshot = task.getResult();
if (documentSnapshot.exists()) {
String anime = documentSnapshot.get("anime").toString();
String art = documentSnapshot.get("art").toString();
String edu = documentSnapshot.get("edu").toString();
String gaming = documentSnapshot.get("gaming").toString();
String music = documentSnapshot.get("music").toString();
String other = documentSnapshot.get("other").toString();
String all = documentSnapshot.get("all").toString();
String search_key = search_keyword.getText().toString().trim();
country = ccp.getSelectedCountryName();
if (all.equals("1") && TextUtils.isEmpty(search_key)) {
setUpRecyclerView(country);
Log.e("explore frag","2");
} else if (all.equals("1") && !(TextUtils.isEmpty(search_key))) {
setUpRecyclerViewWithKeyword(country, search_key);
Log.e("explore frag","3");
} else if (all.equals("0") && TextUtils.isEmpty(search_key)) {
setUpRecyclerViewWithPreferences(country, anime, art, edu, gaming, music, other);
Log.e("explore frag","4");
} else {
setUpRecyclerViewWithKeywordAndPreferences(country, search_key, anime, art, edu, gaming, music, other);
Log.e("explore frag","5");
}
}
}
}
}).addOnFailureListener(new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
}
});
adapter.setOnItemClickListener(
new ExplorePageAdapter.OnItemClickListener() {
@Override
public void OnItemClick(DocumentSnapshot documentSnapshot, int position) {
String id = documentSnapshot.getId();
Intent intent = new Intent(getActivity(),
event_customer_view_activity.class);
intent.putExtra("Event_ID", id);
startActivity(intent);
// getActivity().finish();
}
}
);
}
RecylerView 构建方法
private void setUpRecyclerView(String country) {
Log.e("explore frag",country);
Query query = Cref.whereEqualTo("country", country);
FirestoreRecyclerOptions<POJO_explore_page_item> options = new
FirestoreRecyclerOptions.Builder<POJO_explore_page_item>()
.setQuery(query, POJO_explore_page_item.class).
build();
adapter = new ExplorePageAdapter(options);
RecyclerView recyclerView = getView().findViewById(R.id.explore_recycler);
// recyclerView.setAdapter(null);
// recyclerView.setLayoutManager(null);
// recyclerView.getRecycledViewPool().clear();
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
recyclerView.setAdapter(adapter);
}
我的问题是，每当我尝试重建新的回收器视图时，第一次构建回收器视图时都没有结果。就好像回收站视图消失了一样。
尝试的解决方案：
我之前尝试过添加recyclerView.setAdapter(null); andrecyclerView.setLayoutManager(null);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
recyclerView.setAdapter(adapter);
我也尝试在我的 OnViewCreated 方法中重建回收器视图
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
final String id = FirebaseAuth.getInstance().getCurrentUser().getUid();
search_keyword = getView().findViewById(R.id.exp_search);
search_btn = getView().findViewById(R.id.exp_search_btn);
ccp = getView().findViewById(R.id.exp_ccp);
refresh = getView().findViewById(R.id.refresh);
country = ccp.getSelectedCountryName();
//setUpRecyclerView(country);
///
Log.e("explore frag",country);
Query query = Cref.whereEqualTo("country", country);
FirestoreRecyclerOptions<POJO_explore_page_item> options = new
FirestoreRecyclerOptions.Builder<POJO_explore_page_item>()
.setQuery(query, POJO_explore_page_item.class).
build();
adapter = new ExplorePageAdapter(options);
final RecyclerView recyclerView = getView().findViewById(R.id.explore_recycler);
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
recyclerView.setAdapter(adapter);
///
Log.e("explore frag","1");
db.collection("Users").document(id).collection("preferences").document("event").get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
@Override
public void onComplete(@NonNull Task<DocumentSnapshot> task) {
if (task.isSuccessful()) {
DocumentSnapshot documentSnapshot = task.getResult();
if (documentSnapshot.exists()) {
String anime = documentSnapshot.get("anime").toString();
String art = documentSnapshot.get("art").toString();
String edu = documentSnapshot.get("edu").toString();
String gaming = documentSnapshot.get("gaming").toString();
String music = documentSnapshot.get("music").toString();
String other = documentSnapshot.get("other").toString();
String all = documentSnapshot.get("all").toString();
String search_key = search_keyword.getText().toString().trim();
country = ccp.getSelectedCountryName();
if (all.equals("1") && TextUtils.isEmpty(search_key)) {
// setUpRecyclerView(country);
Query query = Cref.whereEqualTo("country", country);
FirestoreRecyclerOptions<POJO_explore_page_item> options = new
FirestoreRecyclerOptions.Builder<POJO_explore_page_item>()
.setQuery(query, POJO_explore_page_item.class).
build();
adapter = new ExplorePageAdapter(options);
recyclerView.setAdapter(null);
recyclerView.setLayoutManager(null);
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
recyclerView.setAdapter(adapter);
Log.e("explore frag","2");
} else if (all.equals("1") && !(TextUtils.isEmpty(search_key))) {
setUpRecyclerViewWithKeyword(country, search_key);
Log.e("explore frag","3");
} else if (all.equals("0") && TextUtils.isEmpty(search_key)) {
setUpRecyclerViewWithPreferences(country, anime, art, edu, gaming, music, other);
Log.e("explore frag","4");
} else {
setUpRecyclerViewWithKeywordAndPreferences(country, search_key, anime, art, edu, gaming, music, other);
Log.e("explore frag","5");
}
}
}
}
}).addOnFailureListener(new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
}
});
adapter.setOnItemClickListener(
new ExplorePageAdapter.OnItemClickListener() {
@Override
public void OnItemClick(DocumentSnapshot documentSnapshot, int position) {
String id = documentSnapshot.getId();
Intent intent = new Intent(getActivity(),
event_customer_view_activity.class);
intent.putExtra("Event_ID", id);
startActivity(intent);
// getActivity().finish();
}
}
);
}
这两种尝试都没有奏效。有什么建议吗？
【问题讨论】：
-
当使用 recyclerview 和适配器时，您应该只设置一次适配器。之后，如果您的内容已更改，请在适配器中设置更改的项目列表，然后调用 adapter.notifyDataSetChanged() ，您的 recyclerview 将显示更新内容的列表。
-
@just_user 我在原始帖子中使用的 FirebaseUI Firestore 回收器视图是否也是这种情况？如果有，能举个例子吗？
-
对不起，没有。 FirestoreRecyclerAdapter 的情况并非如此。在这个中，内置了快照侦听器，当从 Firebase 接收到更改时，它会调用 notifyDataSetChanged。所以这应该自动完成。我自己从未使用过 FirestoreRecyclerAdapter，但关键是适配器。但一般来说，当您在活动中启动 adapter.startListening() 时，适配器应自行处理并自动更新列表。如果您需要将内容更改为另一个列表，请停止侦听器，创建一个新适配器，然后重新开始侦听。
-
找到本教程：codinginflow.com/tutorials/android/…。根据 Firebase 的经验，如果您将某些内容添加到列表中，请不要尝试在本地强制更新。将其添加到 Firestore 并等待更新到达您的列表。
-
@just_user 您的第二条评论有帮助。我发布了我的解决方案的代表作为答案。
标签： java android android-recyclerview firebaseui