等待在处理之前加载数据

Question

我的代码将逐行处理，而不等待从数据库加载的值， 我的意思是如果它在步骤1中是当前的并且尝试从数据库获取数据它将移动到另一个步骤2而仍然数据不是完全获取  任何人都可以帮助我尽快解决这个问题

private List<ContactInfo> Go(final List<ContactInfo> result) {

    myRef1 = FirebaseDatabase.getInstance().getReference().child("0532").child("TL");


    myRef1.addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            final long[] pendingLoadCount = { dataSnapshot.getChildrenCount() };
            for (DataSnapshot itemSnapshot: dataSnapshot.getChildren()){

                Log.v("ABCD", itemSnapshot.getValue().toString());
                value = itemSnapshot.getValue().toString();
                //    String parts[] = value.split("#");
                final ContactInfo ci = new ContactInfo();
                ci.name = value;
                Query myRef2 = FirebaseDatabase.getInstance().getReference().child("0532").child(DD).child(value);
                myRef2.addListenerForSingleValueEvent(new ValueEventListener() {
                    @Override
                    public void onDataChange(DataSnapshot dataSnapshot) {

                        Map<String ,Object> key = (Map<String, Object>) dataSnapshot.getValue();

                        if(dataSnapshot.hasChild("settime"))
                        {
                      //      Log.v("ABCD", dataSnapshot.getValue().toString());
                            //    Log.v("ABCD", key.values().toString());
                            ci_surname = (String) key.get("settime");
                            ci_email = (String) key.get("settime");
                            ci_title = (String) key.get("settime");


                                Log.v("ABCD", "Nothing found 2"+ci_surname);
                                ci.surname = ci_surname ;
                                ci.email = ci_email ;
                                ci.title = ci_title;
                                result.add(ci);

                        } else{
                            Log.v("ABCD", "Nothing found 2"+ci_surname);
                            ci.surname = "ABCD" ;
                            ci.email = "XYZ" ;
                            ci.title = "FFF";
                            result.add(ci);
                        }

                    }

                    @Override
                    public void onCancelled(DatabaseError databaseError) {

                    }
                });
                pendingLoadCount[0] = pendingLoadCount[0] - 1;
                if (pendingLoadCount[0] == 0) {
                    Log.v("ABCD", "Nothing found");

                    recList.setAdapter(ca);
                }

            }
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });
    return result;
}

Answer 1

Firebase 在AsyncTask中运行，因此您不必使用另一个 AsynTask

等待的最佳方法是使用 ProgressDialog

让我们说你有这个函数返回progressdialog

private ProgressDialog MyProgressDialog() {
            final ProgressDialog progressDialog = new ProgressDialog(getActivity());
            progressDialog.setMessage("loading ...");
            progressDialog.setCancelable(false);
            progressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
            return progressDialog;
        }

然后使用它

        final ProgressDialog myownpd = MyProgressDialog();

并在您的Load_data_from_firebase函数中

private List<ContactInfo> Go(final List<ContactInfo> result) {
            myownpd.show();

    myRef1 = FirebaseDatabase.getInstance().getReference().child("0532").child("TL");


    myRef1.addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            final long[] pendingLoadCount = { dataSnapshot.getChildrenCount() };
            for (DataSnapshot itemSnapshot: dataSnapshot.getChildren()){

                Log.v("ABCD", itemSnapshot.getValue().toString());
                value = itemSnapshot.getValue().toString();
                //    String parts[] = value.split("#");
                final ContactInfo ci = new ContactInfo();
                ci.name = value;
                Query myRef2 = FirebaseDatabase.getInstance().getReference().child("0532").child(DD).child(value);
                myRef2.addListenerForSingleValueEvent(new ValueEventListener() {
                    @Override
                    public void onDataChange(DataSnapshot dataSnapshot) {

                        Map<String ,Object> key = (Map<String, Object>) dataSnapshot.getValue();

                        if(dataSnapshot.hasChild("settime"))
                        {
                      //      Log.v("ABCD", dataSnapshot.getValue().toString());
                            //    Log.v("ABCD", key.values().toString());
                            ci_surname = (String) key.get("settime");
                            ci_email = (String) key.get("settime");
                            ci_title = (String) key.get("settime");


                                Log.v("ABCD", "Nothing found 2"+ci_surname);
                                ci.surname = ci_surname ;
                                ci.email = ci_email ;
                                ci.title = ci_title;
                                result.add(ci);

                        } else{
                            Log.v("ABCD", "Nothing found 2"+ci_surname);
                            ci.surname = "ABCD" ;
                            ci.email = "XYZ" ;
                            ci.title = "FFF";
                            result.add(ci);
                        }

                    }

                    @Override
                    public void onCancelled(DatabaseError databaseError) {

                    }
                });
                pendingLoadCount[0] = pendingLoadCount[0] - 1;
                if (pendingLoadCount[0] == 0) {
                    Log.v("ABCD", "Nothing found");

                    recList.setAdapter(ca);
                }
                                myownpd.cancel();

            }
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {
                                myownpd.cancel();

        }
    });
    return result;
}