Android 要求我将 final 声明为我想在 onclicklistner 函数中多次使用的值

Question

(Already checked the other question, this one is firebase related) Hello, so I am trying to repeatedly use a ref inside onClicklistner, but android studio asks me to declare a value as final, hence it only retrieves one item from the firebase.. This is my code which will show more details

 DatabaseReference myRef = FirebaseDatabase.getInstance().getReference().child("Bathrooms");
        myRef.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull final DataSnapshot dataSnapshot) {



                for ( DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()) {


                    final Bathrooms bathrooms = dataSnapshot1.getValue(Bathrooms.class); // this is where I am asked and forced to create a final.

                    if( bathrooms.getAvailability().equals("Yes")) {


                        bathroomsArrayList.add(bathrooms);


                    }


                Browse.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {

                        if(bathroomsArrayList!=null) {

                            if (bathrooms.getFloor().equals(Floor.getSelectedItem()) &&bathrooms.getSection().equals(Section.getSelectedItem())) {
                                    disable.setChecked(true);
                                    Toast.makeText(getActivity(), "Browse done successfully", Toast.LENGTH_SHORT).show();


                            }

                            else {
                                disable.setChecked(false);
                                Toast.makeText(getActivity(), "No bathrooms", Toast.LENGTH_SHORT).show();


                            }
                        }
                        else {
                            disable.setChecked(false);
                            Toast.makeText(getActivity(), "array empty", Toast.LENGTH_SHORT).show();


                        }

                    }
                });



                }

            }
            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {
                Toast.makeText(getActivity(), "Opsss.... Something is wrong", Toast.LENGTH_SHORT).show();

            }
        });



return rootview;

    }

Answer 1

guy. the first way and actually the easiest one, I use in this situations, is to define your variable before onCreate(), then you can use it at every void you want. think it helps you...

Answer 2

I cannot imagine why AndroidStudio would force you to final here. Suggesting maybe. Anyways, since the variable is defined inside the for loop it will be created newly with each iteration anyways, so it is fine for it to be final -- ie it is initialized directly when it is created and is never assigned a new value.

TL;DR: If your code is not working as expected, it is not the variable being final.