回收器视图在android studio中不显示一张卡视图
我试图通过recycler视图在片段的卡片视图中显示数组列表。数组列表包含五个值,将显示在片段的五个卡片视图上。但它只显示了四个。fragment的代码如下所示:回收器视图在android studio中不显示一张卡视图,android,android-fragments,firebase-realtime-database,android-recyclerview,Android,Android Fragments,Firebase Realtime Database,Android Recyclerview,我试图通过recycler视图在片段的卡片视图中显示数组列表。数组列表包含五个值,将显示在片段的五个卡片视图上。但它只显示了四个。fragment的代码如下所示: public class AddMemberFragment extends Fragment { private RecyclerView mRecyclerView; private RecyclerView.Adapter mAdapter; private RecyclerView.LayoutManager mLayout
public class AddMemberFragment extends Fragment {
private RecyclerView mRecyclerView;
private RecyclerView.Adapter mAdapter;
private RecyclerView.LayoutManager mLayoutManager;
private View view ;
FirebaseUser firebaseUser = FirebaseAuth.getInstance().getCurrentUser();
DatabaseReference mRootRef = FirebaseDatabase.getInstance().getReference();
String userId;
String n_team ;
private ArrayList<Friend> friends;
public AddMemberFragment() {
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {
view = inflater.inflate(R.layout.addnewfriend_fragment, container, false);
return view;
}
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
userId = firebaseUser.getUid();
ManageTeamTabbedActivity activity = (ManageTeamTabbedActivity) getActivity();
n_team = activity.getMyData();
mRecyclerView = (RecyclerView) getView().findViewById(R.id.addNewFriend);
mLayoutManager = new LinearLayoutManager(getActivity());
mRecyclerView.setLayoutManager(mLayoutManager);
mRootRef.child("users").addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
ArrayList<Friend> friendArrayList = new ArrayList<>();
for (DataSnapshot userSnapshot : dataSnapshot.getChildren()) {
Log.d("demo", "USERID " + FirebaseAuth.getInstance().getCurrentUser().getUid());
Friend friend = new Friend();
friend.setId(userSnapshot.getKey());
friend.setFriendName((String) userSnapshot.child("profiles").child("fname").getValue()); //Implement it
friendArrayList.add(friend);
}
friends = friendArrayList;
mAdapter = new AddFriendAdapter(getActivity(), friends, n_team);
mRecyclerView.setAdapter(mAdapter);
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
公共类AddMemberFragment扩展了片段{
私人回收视图mRecyclerView;
专用回收器查看适配器mAdapter;
private RecyclerView.LayoutManager MLLayoutManager;
私人视野;
FirebaseUser FirebaseUser=FirebaseAuth.getInstance().getCurrentUser();
DatabaseReference mRootRef=FirebaseDatabase.getInstance().getReference();
字符串用户标识;
弦乐队;
私人ArrayList朋友;
公共AddMemberFragment(){
}
@可空
@凌驾
创建视图时的公共视图(LayoutFlater充气机、@Nullable ViewGroup容器、Bundle savedInstanceState){
视图=充气机。充气(R.layout.addnewfriend_碎片,容器,false);
返回视图;
}
@凌驾
ActivityCreated上的公共无效(@Nullable Bundle savedinStateCState){
super.onActivityCreated(savedInstanceState);
userId=firebaseUser.getUid();
ManageTeamTabbedActivity=(ManageTeamTabbedActivity)getActivity();
n_team=activity.getMyData();
mRecyclerView=(RecyclerView)getView().findviewbyd(R.id.addNewFriend);
mLayoutManager=新的LinearLayoutManager(getActivity());
mRecyclerView.setLayoutManager(mllayoutmanager);
mRootRef.child(“用户”).addValueEventListener(新的ValueEventListener(){
@凌驾
公共void onDataChange(DataSnapshot DataSnapshot){
ArrayList FriendaryList=新建ArrayList();
对于(DataSnapshot userSnapshot:DataSnapshot.getChildren()){
Log.d(“demo”、“USERID”+FirebaseAuth.getInstance().getCurrentUser().getUid());
朋友=新朋友();
setId(userSnapshot.getKey());
friend.setFriendName((字符串)userSnapshot.child(“profiles”).child(“fname”).getValue();//实现它
friendArrayList.add(friend);
}
朋友=朋友列表;
mAdapter=newaddFriendAdapter(getActivity(),friends,n_团队);
mRecyclerView.setAdapter(mAdapter);
}
@凌驾
已取消的公共void(DatabaseError DatabaseError){
}
});
}
适配器代码写在下面
public class AddFriendAdapter extends RecyclerView.Adapter<AddFriendAdapter.RecyclerViewHolder>{
private ArrayList<Friend> mData;
private Context mContext;
private FirebaseAuth auth;
private String u_team ;
public AddFriendAdapter(Context mContext, ArrayList<Friend> friendList , String u_team) {
this.mData = friendList;
this.mContext = mContext;
this.u_team= u_team;
}
@Override
public RecyclerViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.addnewfriend_layout, parent, false);
AddFriendAdapter.RecyclerViewHolder viewHolder = new AddFriendAdapter.RecyclerViewHolder(view);
return viewHolder;
}
@Override
public void onBindViewHolder(RecyclerViewHolder holder, final int position) {
final Friend frnd =(Friend) mData.get(position);
holder.friendName.setText(frnd.getFriendName());
holder.addFriend.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
frnd.setStatus("sent");
final DatabaseReference mRootRef = FirebaseDatabase.getInstance().getReference();
final FirebaseUser firebaseUser = FirebaseAuth.getInstance().getCurrentUser();
final String UID = firebaseUser.getUid();
mRootRef.child("users").addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
mRootRef.child("users").child(UID).child("Your Teams").child("requests").child(frnd.getId()).setValue(frnd);
Friend temp = new Friend();
temp.setId(firebaseUser.getUid());
temp.setFriendName(firebaseUser.getDisplayName());
temp.setStatus("received");
mRootRef.child("users").child(frnd.getId()).child("Your Teams ").child("requests").child(firebaseUser.getUid()).setValue(temp);
mData.remove(frnd);
notifyDataSetChanged();
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
});
}
@Override
public int getItemCount() {
return mData.size();
}
public class RecyclerViewHolder extends RecyclerView.ViewHolder {
TextView friendName;
ImageButton addFriend;
public RecyclerViewHolder(View itemView) {
super(itemView);
friendName = (TextView)itemView.findViewById(R.id.textViewFriendName);
addFriend = (ImageButton) itemView.findViewById(R.id.imagebuttonFriendAdd);
}
}
公共类AddFriendAdapter扩展了RecyclerView.Adapter
我自己调试了很久,发现数组列表中的条目如预期的有五个
还附上了数据库图片以供参考。如图所示,它还有五个ID要显示,但“回收者”视图显示了四个ID。由于此限制,我将我的评论放在了回答字段中:“你必须有50个声誉才能发表评论” 将
Log.d()
放入onBindViewHolder
中以监视值如何?
在ActivityCreated()上使用“断点”分析数据不是一个好主意,因为UI可能还没有完全填充。此外,您还可以添加第6条记录,它是否显示4条或5条记录?这样,您可以确定这是最后一条记录还是其他问题。当您打印ArrayList时,Android显示了什么?我通过Log.d()打印它在onBindViewHolder中,获得了正确的值数。我还添加了第6条记录。这六个值在数组列表中显示得非常正确。使用卡片视图打印此数组列表时,可能出现了一些问题。这行不是
mData.remove(frnd)吗
导致这种行为?我评论说问题仍然没有解决。所以我不认为是它导致了这种行为。我通过Log.d()打印了它在onBindViewHolder中,获得了正确的值数。我还添加了第6条记录。这六个值在数组列表中显示得非常正确。使用卡片视图打印此数组列表时,可能出现了一些问题。