android java循环中的firestore查询

我不熟悉

java

。我有一个

firestore\u会员名单

。在firestore成员列表中，它包含以下值：

[“steve”、“ram”、“kam”]

。我使用

for

循环逐个传递值

loadingbar.show()
for( int k=0; k<firestore_member_list.size();k++){
        String member_name = firestore_member_list.get(k);
        final DocumentReference memDataNameCol = firestoredb.collection("member_collection").document(member_name);
        memDataNameCol.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
        @Override
        public void onComplete(@NonNull Task<DocumentSnapshot> task) {
                if (task.isSuccessful()) {
                DocumentSnapshot document = task.getResult();
                if (document.exists()) {
//                      In here, I am retreiveing the document data from firestore and assigning it to the ArrayList which is `all_mem_data`

                        all_mem_data.add(document.get("member_name").toString());
                        all_mem_data.add(document.get("member_address").toString());
                        Toast.makeText(getActivity(), "all mem data array"+all_mem_data.toString(),
                                Toast.LENGTH_LONG).show();
                }
                }
        }
        });
}
Log.d("all_mem_data",all_mem_data)
loadingbar.hide()

loadingbar.show（）
对于（int k=0；k任何需要数据库数据的代码，都需要在数据可用时触发的
onComplete
中

如果要等待所有文档加载完毕，例如，您可以保留一个计数器：

loadingbar.show()
int completeCount = 0;
for( int k=0; k<firestore_member_list.size();k++){
    String member_name = firestore_member_list.get(k);
    final DocumentReference memDataNameCol = firestoredb.collection("member_collection").document(member_name);
    memDataNameCol.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
        @Override
        public void onComplete(@NonNull Task<DocumentSnapshot> task) {
            ...

            if (completeCount++ == firestore_member_list.size()-1) {
                Log.d("all_mem_data",all_mem_data)
                loadingbar.hide()
            }
        }
    });

}

loadingbar.show（）
int completeCount=0；
对于（int k=0；k