I want to remove the string "childid1" from the list containing "chilidid1,childid2,childid3,..." From firebase realtime

I want to remove the string "childid1" from the list containing "chilidid1,childid2,childid3,..." From firebase realtime

CodePudding user response：

I guess that database you made is for learning how a real time database works on firebase.

Your database strtucture is wrong. You should redo-it and make it like this:

-classid1
     -children:
          -child1: ""
          -child2: ""

You cannot have multiple values in a child key unless it is a list. In that case, you need to create a DatabaseReference that gets the value and classifies it to a list, then you do whatever you want with that list and then post it back to the database. Example:

         DatabaseReference childsRef = FirebaseDatabase.getInstance().getReference().child("classes").child("classid1");
    
    childsRef.addListenerForSingleValueEvent(new ValueEventListener() {
     @Override
                public void onDataChange(@NonNull @NotNull DataSnapshot snapshot) {
                    ArrayList[] childrenList = 
                    snapshot.child("children").getValue(List.class);
                    childrenList[0] = "changedchild1"
                    snapshot.child("children").setValue(childrenList[0]);
                }
    
                @Override
                public void onCancelled(@NonNull @NotNull DatabaseError error) {
    
                }
    }

If you want to remove the child programmatically, simply change this on the code I placed before, inside onDataChange method:

public void onDataChange(@NonNull @NotNull DataSnapshot snapshot) {  
                    snapshot.child("children").removeValue();
                }

CodePudding user response：

The property called children in your database is actually a single string value. To remove the child1 substring from it, you'll have to:

1. Read the entire children property into your application code.
2. Modify the string to remove the (first) child1.
3. Write the modified string back to the database.

Alternatively you can do what OneKe answered and turn the children property into a list (using push() to generate the keys) or into a map (where child1 and all are keys and they all have a value of true).