回收站 View 未显示项目。 datasnapshot2 正在接收正确的值。
child("Trips").child(tripID).child("Members") 正在获取 userID
membersRecyclerView = findViewById(R.id.members);
membersRecyclerView.setLayoutManager(new LinearLayoutManager(this));
membersRecyclerView.setItemAnimator(new DefaultItemAnimator());
DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference().child("Trips").child(tripID).child("Members");
databaseReference.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()) {
for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()) {
DatabaseReference databaseReference1 = FirebaseDatabase.getInstance().getReference().child("Users")
.child(Objects.requireNonNull(dataSnapshot1.getKey()));
databaseReference1.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot2) {
UserDataModel userDataModel = dataSnapshot2.getValue(UserDataModel.class);
membersArrayList.add(userDataModel);
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
}
membersAdapter = new UserDataAdapter(membersArrayList);
membersRecyclerView.setAdapter(membersAdapter);
}
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
适配器
public class UserDataAdapter extends RecyclerView.Adapter<UserDataAdapter.ViewHolder> {
private List<UserDataModel> MemberList;
private TextView userName, userRating;
UserDataAdapter(List<UserDataModel> MemberList) {
this.MemberList = MemberList;
}
@NonNull
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.members_list_item, parent, false);
return new ViewHolder(view);
}
@SuppressLint("SetTextI18n")
@Override
public void onBindViewHolder(@NonNull ViewHolder holder, final int position) {
UserDataModel userDataModel = MemberList.get(position);
userName.setText(userDataModel.getUserName());
userRating.setText(userDataModel.getUserRating());
}
@Override
public int getItemCount() {
return MemberList.size();
}
class ViewHolder extends RecyclerView.ViewHolder {
ViewHolder(View itemView) {
super(itemView);
userImage = itemView.findViewById(R.id.m_user_image);
userName = itemView.findViewById(R.id.m_user_name);
userRating = itemView.findViewById(R.id.m_user_rating);
}
}
}
用户数据模型
public class UserDataModel {
public String userName, userEmail, contactNumber, gender, dateOfBirth, location, userID, createdDate, createdTime;
int userRating;
public UserDataModel() {
}
UserDataModel(String userName, String userEmail, String contactNumber, String gender, String dateOfBirth, String location, String userID, String createdDate, String createdTime) {
this.userName = userName;
this.userEmail = userEmail;
this.contactNumber = contactNumber;
this.gender = gender;
this.dateOfBirth = dateOfBirth;
this.location = location;
this.userID = userID;
this.createdDate = createdDate;
this.createdTime = createdTime;
}
String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
String getUserEmail() {
return userEmail;
}
public void setUserEmail(String userEmail) {
this.userEmail = userEmail;
}
String getContactNumber() {
return contactNumber;
}
public void setContactNumber(String contactNumber) {
this.contactNumber = contactNumber;
}
String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
String getDateOfBirth() {
return dateOfBirth;
}
public void setDateOfBirth(String dateOfBirth) {
this.dateOfBirth = dateOfBirth;
}
String getLocation() {
return location;
}
public void setLocation(String location) {
this.location = location;
}
String getUserID() {
return userID;
}
public void setUserID(String userID) {
this.userID = userID;
}
public String getCreatedDate() {
return createdDate;
}
public void setCreatedDate(String createdDate) {
this.createdDate = createdDate;
}
public String getCreatedTime() {
return createdTime;
}
public void setCreatedTime(String createdTime) {
this.createdTime = createdTime;
}
public int getUserRating() {
return userRating;
}
public void setUserRating(int userRating) {
this.userRating = userRating;
}
}
xml(删除了一些内容)
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".TripActivity">
<ScrollView
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:id="@+id/createdBy"
android:layout_width="match_parent"
android:layout_height="110dp">
<de.hdodenhof.circleimageview.CircleImageView
android:id="@+id/createdBy_user_image"
android:layout_width="95dp"
android:layout_height="95dp"
android:layout_marginHorizontal="10dp"
android:layout_marginTop="10dp"
android:scaleType="centerCrop"
android:src="@color/black" />
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:layout_marginTop="10dp"
android:background="@color/darkgrey" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:fontFamily="@font/heebo_medium"
android:text="Trip Description"
android:textColor="@color/black"
android:textSize="16sp" />
<TextView
android:id="@+id/trip_description"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fontFamily="@font/heebo_light"
android:text="This is the description of trip." />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:fontFamily="@font/heebo_medium"
android:text="Members"
android:textColor="@color/black"
android:textSize="16sp" />
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/members"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:scrollbars="none" />
</LinearLayout>
</LinearLayout>
</ScrollView>
</RelativeLayout>
最佳答案
我看到您在类中添加了许多未使用的字段UserDataModel:
尝试更改您的UserDataModel:
public class UserDataModel {
//these must be named exactly like your database, and the exact same number
private String userName;
private String userEmail;
private String userID;
private String contactNumber;
private String gender;
private String dateOfBirth;
private String location;
//constructor
public UserDataModel(String userName,String userEmail,String userID,String contactNumber,String gender,String dateOfBirth,String location){
this.userName = userName;
this.userEmail = userEmail;
this.userID = userID;
this.contactNumber=contactNumber;
this.gender = gender;
this.dateOfBirth = dateOfBirth;
this.location = location;
}
//generate also getters and setters........
}
您还必须做的一件事:
你看到这些代码行了吗:
membersAdapter = new UserDataAdapter(membersArrayList);
membersRecyclerView.setAdapter(membersAdapter);
将它们直接添加到这些行下:
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot2) {
UserDataModel userDataModel = dataSnapshot2.getValue(UserDataModel.class);
membersArrayList.add(userDataModel);
//here......
membersAdapter = new UserDataAdapter(membersArrayList);
membersRecyclerView.setAdapter(membersAdapter);
.....
.....
.....
更新2:
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/members"
android:layout_width="match_parent"
android:layout_height="match_parent"
...............
关于java - 回收者 View 不显示项目，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/61549323/