Question

我按照firebase数据库中的文档建议对数据进行了非规范化。使用组列表，用户是我存储在：value中的成员。但是，使用this suggestion在FirebaseUI中使用此列表时，在滚动浏览大型列表时，附加侦听器会导致性能瓶颈。

每次用户滚动列表时，是否有任何方式不附加侦听器？或者使用引用数据库中另一个位置的大量布尔值来减少性能问题的任何其他方法？

Answer 1

https://firebase.google.com/docs/database/android/retrieve-data#child-events

您只需要附加一个监听器child_changed

ChildEventListener childEventListener = new ChildEventListener() {
    @Override
    public void onChildAdded(DataSnapshot dataSnapshot, String previousChildName) {
        Log.d(TAG, "onChildAdded:" + dataSnapshot.getKey());

        // A new comment has been added, add it to the displayed list
        Comment comment = dataSnapshot.getValue(Comment.class);

        // ...
    }

    @Override
    public void onChildChanged(DataSnapshot dataSnapshot, String previousChildName) {
        Log.d(TAG, "onChildChanged:" + dataSnapshot.getKey());

        // A comment has changed, use the key to determine if we are displaying this
        // comment and if so displayed the changed comment.
        Comment newComment = dataSnapshot.getValue(Comment.class);
        String commentKey = dataSnapshot.getKey();

        // ...
    }

    @Override
    public void onChildRemoved(DataSnapshot dataSnapshot) {
        Log.d(TAG, "onChildRemoved:" + dataSnapshot.getKey());

        // A comment has changed, use the key to determine if we are displaying this
        // comment and if so remove it.
        String commentKey = dataSnapshot.getKey();

        // ...
    }

    @Override
    public void onChildMoved(DataSnapshot dataSnapshot, String previousChildName) {
        Log.d(TAG, "onChildMoved:" + dataSnapshot.getKey());

        // A comment has changed position, use the key to determine if we are
        // displaying this comment and if so move it.
        Comment movedComment = dataSnapshot.getValue(Comment.class);
        String commentKey = dataSnapshot.getKey();

        // ...
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {
        Log.w(TAG, "postComments:onCancelled", databaseError.toException());
        Toast.makeText(mContext, "Failed to load comments.",
                Toast.LENGTH_SHORT).show();
    }
};
ref.addChildEventListener(childEventListener);

Firebase中布尔数据列表的性能问题

1 个答案: