问题描述
我的firebase控制台中有以下结构。我试图读取值,并显示所有的用户,但populateViewHolder永远不会被调用。 用户
+ OW5BYennVRXvfzOjfKpup9rZEYv2
-email:[email protected]
-username:abc
在下面的代码中,我收到的物品计数为1 / b
pre $ m $ c $ mAdapter.registerAdapterDataObserver(new RecyclerView.AdapterDataObserver(){
@Override
public void onItemRangeInserted(int positionStart,int itemCount){
super.onItemRangeInserted(positionStart,itemCount);
int friendlyMessageCount = mAdapter.getItemCount();
int lastVisiblePosition =
mManager.findLastCompletelyVisibleItemPosition();
//如果回收者视图最初被加载或者
//用户在列表底部,滚动到底部
//列表显示新添加的消息智者。
if(lastVisiblePosition == -1 ||
(positionStart> =(friendlyMessageCount - 1)&&
lastVisiblePosition ==(positionStart - 1))){
recyclerView.scrollToPosition(positionStart);
}
}
});
这里是我的代码
@Override
public view onCreateView(LayoutInflater inflater,ViewGroup container,
Bundle savedInstanceState){
super.onCreateView(inflater,container,savedInstanceState);
查看rootView = inflater.inflate(R.layout.fragment_home_page,container,false);
mDatabase = FirebaseDatabase.getInstance()。getReference();
recyclerView =(RecyclerView)rootView.findViewById(R.id.recycler_view);
recyclerView.setHasFixedSize(true);
return rootView;
}
@Override
public void onActivityCreated(Bundle savedInstanceState){
super.onActivityCreated(savedInstanceState);
mManager = new LinearLayoutManager(getActivity());
mManager.setReverseLayout(true);
mManager.setStackFromEnd(true);
Query postsQuery = mDatabase.child(users);
mAdapter = new FirebaseRecyclerAdapter< User,PostViewHolder>(User.class,R.layout.post,
PostViewHolder.class,postsQuery){
@Override
保护void populateViewHolder(PostViewHolder viewHolder,User model,int position){
final DatabaseReference postRef = getRef(position);
final String postKey = postRef.getKey();
viewHolder.bindToPost(model);
}
};
mAdapter.registerAdapterDataObserver(new RecyclerView.AdapterDataObserver(){
@Override $ b $ public void onItemRangeInserted(int positionStart,int itemCount){
super.onItemRangeInserted(positionStart, itemCount);
int friendlyMessageCount = mAdapter.getItemCount();
int lastVisiblePosition =
mManager.findLastCompletelyVisibleItemPosition();
//如果回收者视图最初被加载或
//用户位于列表的底部,滚动到列表的底部
//显示新添加的消息
if(lastVisiblePosition == -1 ||
(positionStart> =(friendlyMessageCount - 1)&
lastVisiblePosition ==(positionStart - 1))){
recyclerView.scrollToPosition(positionStart);
}
}
});
recyclerView.setAdapter(mAdapter);
$ / code>
PlaceHolder:
public class PostViewHolder extends RecyclerView.ViewHolder {
public TextView title,emailt;
public PostViewHolder(View view){
super(view);
title =(TextView)view.findViewById(R.id.title);
emailt =(TextView)view.findViewById(R.id.count);
$ b public void bindToPost(User post,View.OnClickListener starClickListener){
title.setText(post.username);
emailt.setText(post.email +Likes);
$ b public void bindToPost(User post){
title.setText(post.username);
emailt.setText(post.email +Likes);
$ / code $ / pre
解决方案问题是RecyclerView有一个WrapContent的高度,所以请确保您的回收站高度设置为Match_Parent。
< android.support.v7.widget.RecyclerView
android:id =
android:layout_width =match_parent
android:layout_height =match_parent
android:scrollbars =vertical
/>
I have below structure in my firebase console . I am trying to read the values and display all the users but populateViewHolder never gets called.
users
+OW5BYennVRXvfzOjfKpup9rZEYv2
-email: "[email protected]"
-username: "abc"
While in the below code I receive the item count as 1
mAdapter.registerAdapterDataObserver(new RecyclerView.AdapterDataObserver() {
@Override
public void onItemRangeInserted(int positionStart, int itemCount) {
super.onItemRangeInserted(positionStart, itemCount);
int friendlyMessageCount = mAdapter.getItemCount();
int lastVisiblePosition =
mManager.findLastCompletelyVisibleItemPosition();
// If the recycler view is initially being loaded or the
// user is at the bottom of the list, scroll to the bottom
// of the list to show the newly added message.
if (lastVisiblePosition == -1 ||
(positionStart >= (friendlyMessageCount - 1) &&
lastVisiblePosition == (positionStart - 1))) {
recyclerView.scrollToPosition(positionStart);
}
}
});
Here is my code
@Override
public View onCreateView (LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
super.onCreateView(inflater, container, savedInstanceState);
View rootView = inflater.inflate(R.layout.fragment_home_page, container, false);
mDatabase = FirebaseDatabase.getInstance().getReference();
recyclerView = (RecyclerView) rootView.findViewById(R.id.recycler_view);
recyclerView.setHasFixedSize(true);
return rootView;
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
mManager = new LinearLayoutManager(getActivity());
mManager.setReverseLayout(true);
mManager.setStackFromEnd(true);
Query postsQuery = mDatabase.child("users");
mAdapter = new FirebaseRecyclerAdapter<User, PostViewHolder>(User.class, R.layout.post,
PostViewHolder.class, postsQuery) {
@Override
protected void populateViewHolder(PostViewHolder viewHolder, User model, int position) {
final DatabaseReference postRef = getRef(position);
final String postKey = postRef.getKey();
viewHolder.bindToPost(model);
}
};
mAdapter.registerAdapterDataObserver(new RecyclerView.AdapterDataObserver() {
@Override
public void onItemRangeInserted(int positionStart, int itemCount) {
super.onItemRangeInserted(positionStart, itemCount);
int friendlyMessageCount = mAdapter.getItemCount();
int lastVisiblePosition =
mManager.findLastCompletelyVisibleItemPosition();
// If the recycler view is initially being loaded or the
// user is at the bottom of the list, scroll to the bottom
// of the list to show the newly added message.
if (lastVisiblePosition == -1 ||
(positionStart >= (friendlyMessageCount - 1) &&
lastVisiblePosition == (positionStart - 1))) {
recyclerView.scrollToPosition(positionStart);
}
}
});
recyclerView.setAdapter(mAdapter);
}
PlaceHolder :
public class PostViewHolder extends RecyclerView.ViewHolder {
public TextView title, emailt;
public PostViewHolder(View view) {
super(view);
title = (TextView) view.findViewById(R.id.title);
emailt = (TextView) view.findViewById(R.id.count);
}
public void bindToPost(User post, View.OnClickListener starClickListener) {
title.setText(post.username);
emailt.setText(post.email + "Likes");
}
public void bindToPost(User post) {
title.setText(post.username);
emailt.setText(post.email + "Likes");
}
}
解决方案 The Problem is RecyclerView had a height of WrapContent , So Please Make Sure your recycler Height is set to Match_Parent. This will fix this issue.
<android.support.v7.widget.RecyclerView
android:id="@+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scrollbars="vertical"
/>
这篇关于Firebase populateViewHolder永远不会被调用的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!