I am trying to populate a recycler view using nested queries. The first query goes to groups_list node and takes data in the node and the unique key. Then it goes to groups node with the key and gets data under that key. The result of both the queries needs to be updated in recycler view.
In short, the first query gets some data and a key, the key is used to make the second query. The result from both these queries need to be updated in the recycler view. I am using a model class and recycler view adapter for this.
But I am getting an error below.
My Fragment is as follows:
// Firebase
fbDatabaseRootNode = FirebaseDatabase.getInstance().getReference();
fbDatabaseRefGroupList = fbDatabaseRootNode.child("groups_list").child(current_user_id);
fbDatabaseRefGroups = fbDatabaseRootNode.child("groups");
fbDatabaseRefGroupList.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
// Array to Get Group List
lGroupsList = new ArrayList<>();
if (dataSnapshot.exists()) {
// Clear Array to Get Group List
lGroupsList.clear();
for (DataSnapshot glSnapshot : dataSnapshot.getChildren()) {
// Use The Model To Format Array List and Pass It Into It
GroupsListModel g = glSnapshot.getValue(GroupsListModel.class);
// Array to Get Group List
lGroupsList.add(g);
String groupID = String.valueOf(glSnapshot.getKey());
fbDatabaseRefGroups.child(groupID).addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()) {
for (DataSnapshot gSnapshot : dataSnapshot.getChildren()) {
// Use The Model To Format Array List and Pass It Into It
GroupsListModel g = gSnapshot.getValue(GroupsListModel.class);
// Array to Get Group List
lGroupsList.add(g);
}
}
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
}
aGroupList = new GroupsListAdapter(getContext(), lGroupsList);
rvGroupList.setAdapter(aGroupList);
}
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
System.out.println("The read failed: " + databaseError.getCode());
}
});
And My Firebase Database Structure Looks Like
"groups" : {
"-LaPfENd0G4pHlejrcd6" : {
"group_creation_date" : 1553078221782,
"group_logo" : "0",
"group_member_count" : "0",
"group_name" : "dog lovers",
"group_tagline" : "we love dogs..."
},
"-LaPhG0YHnF3FG0Czxom" : {
"group_creation_date" : 1553078751686,
"group_logo" : "0",
"group_member_count" : "0",
"group_name" : "hi",
"group_tagline" : "hello"
}
},
"groups_list" : {
"F81wvGx9a7fXRrfVPQMhQtkM0wv2" : {
"-LaPfENd0G4pHlejrcd6" : {
"block_status" : "0",
"hide_status" : "0",
"notification_status" : "0",
"pin_sequence" : "0",
"report_status" : "0"
},
"-LaPhG0YHnF3FG0Czxom" : {
"block_status" : "0",
"hide_status" : "0",
"notification_status" : "0",
"pin_sequence" : "0",
"report_status" : "0"
}
}
},
The Model Class Is
public class GroupsListModel {
private String block_status;
private String hide_status;
private String notification_status;
private String pin_sequence;
private String report_status;
private String group_name;
private Long group_creation_date;
private String group_logo;
private String group_member_count;
private String group_tagline;
public GroupsListModel() {
}
public GroupsListModel(String block_status, String hide_status, String notification_status, String pin_sequence, String report_status, String group_name, Long group_creation_date, String group_logo, String group_member_count, String group_tagline) {
this.block_status = block_status;
this.hide_status = hide_status;
this.notification_status = notification_status;
this.pin_sequence = pin_sequence;
this.report_status = report_status;
this.group_name = group_name;
this.group_creation_date = group_creation_date;
this.group_logo = group_logo;
this.group_member_count = group_member_count;
this.group_tagline = group_tagline;
}
public String getBlock_status() {
return block_status;
}
public void setBlock_status(String block_status) {
this.block_status = block_status;
}
public String getHide_status() {
return hide_status;
}
public void setHide_status(String hide_status) {
this.hide_status = hide_status;
}
public String getNotification_status() {
return notification_status;
}
public void setNotification_status(String notification_status) {
this.notification_status = notification_status;
}
public String getPin_sequence() {
return pin_sequence;
}
public void setPin_sequence(String pin_sequence) {
this.pin_sequence = pin_sequence;
}
public String getReport_status() {
return report_status;
}
public void setReport_status(String report_status) {
this.report_status = report_status;
}
public String getGroup_name() {
return group_name;
}
public void setGroup_name(String group_name) {
this.group_name = group_name;
}
public Long getGroup_creation_date() {
return group_creation_date;
}
public void setGroup_creation_date(Long group_creation_date) {
this.group_creation_date = group_creation_date;
}
public String getGroup_logo() {
return group_logo;
}
public void setGroup_logo(String group_logo) {
this.group_logo = group_logo;
}
public String getGroup_member_count() {
return group_member_count;
}
public void setGroup_member_count(String group_member_count) {
this.group_member_count = group_member_count;
}
public String getGroup_tagline() {
return group_tagline;
}
public void setGroup_tagline(String group_tagline) {
this.group_tagline = group_tagline;
}
}
And The Error is
Can't convert object of type java.lang.Long to type com.example.myproject
The logs from datasnapshots are coming as follows... first one... 
The log from second one... 
Possible Solution 1 (Not Working)
This seems to be getting the data in proper sequence now just have to pass it into the Model Array List and Set The Adapter
// Get The Data
fbDatabaseRefGroupList.addChildEventListener(new ChildEventListener() {
@Override
public void onChildAdded(@NonNull DataSnapshot dataSnapshot, @Nullable String s) {
if (dataSnapshot.exists()) {
final String groupID = dataSnapshot.getKey();
final String blockStatus = (String) dataSnapshot.child("block_status").getValue();
final String hideStatus = (String) dataSnapshot.child("hide_status").getValue();
final String notificationStatus = (String) dataSnapshot.child("notification_status").getValue();
final String pinSequence = (String) dataSnapshot.child("pin_sequence").getValue();
final String reportStatus = (String) dataSnapshot.child("report_status").getValue();
fbDatabaseRefGroups.child(groupID).addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
String groupName = (String) dataSnapshot.child("group_name").getValue();
String groupTagLine = (String) dataSnapshot.child("group_name").getValue();
String groupMemberCount = (String) dataSnapshot.child("group_name").getValue();
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
}
}
@Override
public void onChildChanged(@NonNull DataSnapshot dataSnapshot, @Nullable String s) {
}
@Override
public void onChildRemoved(@NonNull DataSnapshot dataSnapshot) {
}
@Override
public void onChildMoved(@NonNull DataSnapshot dataSnapshot, @Nullable String s) {
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
Possible Solution 2 (Not Working)
// Firebase
fbDatabaseRootNode = FirebaseDatabase.getInstance().getReference();
fbDatabaseRefGroupList = fbDatabaseRootNode.child("groups_list").child(current_user_id);
fbDatabaseRefGroups = fbDatabaseRootNode.child("groups");
// Array to Get Group List
lGroupsList = new ArrayList<>();
lGroupsList2 = new ArrayList<>();
ValueEventListener valueEventListener = new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot ds : dataSnapshot.getChildren()) {
Log.d(TAG, "groups_list: " +ds);
// Clear Array to Get Group List
lGroupsList.clear();
// Use The Model To Format Array List and Pass It Into It
GroupsListModel g = dataSnapshot.getValue(GroupsListModel.class);
// Array to Get Group List
lGroupsList.add(g);
String key = ds.getKey();
DatabaseReference keyRef = fbDatabaseRootNode.child("groups").child(key);
ValueEventListener eventListener = new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
Log.d(TAG, "groups: " +dataSnapshot);
// Clear Array to Get Group List
lGroupsList2.clear();
// Use The Model To Format Array List and Pass It Into It
GroupsListModel g = dataSnapshot.getValue(GroupsListModel.class);
// Array to Get Group List
lGroupsList2.add(g);
// Joining The Arrays To Get One Array
lGroupsList.addAll(lGroupsList2);
// Log.d(TAG, "onDataChange: " + lGroupsList);
aGroupList = new GroupsListAdapter(getContext(), lGroupsList);
rvGroupList.setAdapter(aGroupList);
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
Log.d(TAG, databaseError.getMessage()); //Don't ignore errors!
}
};
keyRef.addListenerForSingleValueEvent(eventListener);
}
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
Log.d(TAG, databaseError.getMessage()); //Don't ignore errors!
}
};
fbDatabaseRefGroupList.addListenerForSingleValueEvent(valueEventListener);
@Prateek Jain Your answer is giving error please see screenshot below: 
from Populating Recycler View From Nested Queries in Firebase
No comments:
Post a Comment