如何将实时 Firebase 数据库中的数据提取到数组中？我希望将数组中的静态数据更改为 firebase 数据

Question

我创建了一个自定义日历，它使用从 github 链接 https://github.com/DeveloperBrothers/Custom-Calendar-View 获取的数组“HomeCollection”，以便在我的 android 应用程序中创建自定义日历。目前，事件数据被硬编码到这个数组中（参见下面的代码 sn-p），但希望从我的 firebase 数据库中获取事件属性，而不是在我创建数据库并保存此类事件数据的地方（参见下面的图片链接）。

HomeCollection.date_collection_arr = new ArrayList<HomeCollection>();
        HomeCollection.date_collection_arr.add(new HomeCollection("2018-11-21", "Winter Table Quiz", "7-10 pm, Clubhouse", "ClubHouse", "Come along to the Winter Table Quiz, €5pp, tables of 4, theres lots of great prizes to be won."));
       HomeCollection.date_collection_arr.add(new HomeCollection("2018-11-03", "u21 Division 1 Training ", "10-11am, Club Grounds", "ClubHouse", "Weekly Division 1 training. Weather dependant."));
        HomeCollection.date_collection_arr.add(new HomeCollection("2018-11-03", "u21 Division 2 Training ", "11-12am, Club Grounds", "ClubHouse", "Weekly Division 2 training. Weather dependant."));
        HomeCollection.date_collection_arr.add(new HomeCollection("2018-11-10", "u21 Division 1 Training ", "10-11am, Club Grounds", "ClubHouse", "Weekly Division 1 training. Weather dependant."));
        HomeCollection.date_collection_arr.add(new HomeCollection("2018-11-10", "u21 Division 2 Training ", "11-12am, Club Grounds", "ClubHouse", "Weekly Division 2 training. Weather dependant."));
        HomeCollection.date_collection_arr.add(new HomeCollection("2018-11-17", "u21 Division 1 Training ", "10-11am, Club Grounds", "ClubHouse", "Weekly Division 1 training. Weather dependant."));
        HomeCollection.date_collection_arr.add(new HomeCollection("2018-11-17", "u21 Division 2 Training ", "11-12am, Club Grounds", "ClubHouse", "Weekly Division 2 training. Weather dependant."));
        HomeCollection.date_collection_arr.add(new HomeCollection("2018-11-24", "u21 Division 1 Training ", "10-11am, Club Grounds", "ClubHouse", "Weekly Division 1 training. Weather dependant."));
        HomeCollection.date_collection_arr.add(new HomeCollection("2018-11-24", "u21 Division 2 Training ", "11-12am, Club Grounds", "ClubHouse", "Weekly Division 2 training. Weather dependant."));*/
        cal_month = (GregorianCalendar) GregorianCalendar.getInstance();
        cal_month_copy = (GregorianCalendar) cal_month.clone();
        hwAdapter = new HwAdapter(this, cal_month, HomeCollection.date_collection_arr);

谁能帮我将此静态代码更改为我的 Firebase 数据库数据？

Link to my firebase JSON events tree image

Answer 1

因此，您可以制作一个 Java bean 来保存所有这些数据。为您作为对象存储的所有数据创建getter 和setter 方法。例如，为对象属性创建 getter 和 setter 方法，例如：eventDate、eventDescription 等，并假设您将 bean 命名为 EventBean.java。

现在像这样使用childEventListener：

mDatabaseReference = mFirebaseDatabase.getReference().getChild("event");
mDatabaseReference.addChildEventListener(new OnChildEventListener(){

@Override
public void onChildAdded(DataSnapshot snapshot, String previousChildName){
EventBean data = snapshot.getValue(EventBean.class);//now you have got data in the 
eventbean instance
System.out.println(data.getEventDate());
}
});

我希望这就是你要找的。​​p>

Answer 2

1) 您必须在代码中获取 firebase 数据引用

DatabaseReference mFireBaseDatabaseReference = FirebaseDatabase.getInstance().getReference();

2) 然后你添加了 firebase 监听器来获取数据：

mFireBaseDatabaseReference.child("events").addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {

                //you can parse the data in your models here like this
for (DataSnapshot childSnapshot: dataSnapshot.getChildren()) {
Event event = childSnapshot.getValue(Event.class);
HomeCollection.date_collection_arr.add(event);
}
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {

            }
        });