如何在删除导致无限循环的对象时修复基于Android的Firebase错误？

Question

I am developing an app using Firebase. In one of my activities, I have added a delete functionality. But when I delete a node and monitor the behaviour in the Firebase console.

First it deletes the object, adds 2 more. Then deletes the 2, adds 3-4 more. This operation continues to such an extent that the device becomes unstable (gets stuck in an infinite loop). The app causes the screen to go completely black. Nothing works. Logcat shows "too much output to process." Navigation buttons takes the user back the the unstable app.

It does not Uninstall. The only solution is to force reboot it. The code used to do this operation was

mChatsListView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
        @Override
        public boolean onItemLongClick(AdapterView<?> parent, View view, final int position, long id) {
            chatToDelete = ((TextView) view.findViewById(R.id.sender_roll_text_view)).getText().toString().trim();
            final AlertDialog.Builder builder = new AlertDialog.Builder(ChatsActivity.this);
            builder.setMessage("Delete Chat?").setPositiveButton("Delete", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    Query query = mDatabaseReference.orderByChild("roll").equalTo(chatToDelete);
                    query.addValueEventListener(new ValueEventListener() {
                        @Override
                        public void onDataChange(DataSnapshot dataSnapshot) {
                            for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()) {
                                dataSnapshot1.getRef().removeValue();
                                chats.remove(position);
                                mChatsAdapter.notifyDataSetChanged();
                            }
                        }

                        @Override
                        public void onCancelled(DatabaseError databaseError) {}
                    });
                }
            }).setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    dialog.dismiss();
                }
            });
            builder.show();
            return true;
        }
    });

This code was working fine just yesterday. But now it is a huge problem. So, please do help if you figure it out. Thanks.

Answer 1

I think it happen because you use addValueEventListener instead of addListenerForSingleValueEvent . By using addValueEventListener the onDataChange will be triggered every time database is changed.

Inside onClick please change from

query.addValueEventListener to query.addListenerForSingleValueEvent

This should solve your problem