DatabaseReference ridesRef = database.getReference("rides");
ridesRef.equalTo(from).orderByChild("from").addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
Log.i(TAG, "dataSnapshot.getChildrenCount(): " + dataSnapshot.getChildrenCount());
if (dataSnapshot.getChildrenCount() > 0) {
ArrayList<Ride> value = (ArrayList<Ride>) dataSnapshot.getValue();
Log.i(TAG, value.toString());
for (Ride r : value) { // error occurs here
Log.i(TAG, "r.getTime:" + r.getTime());
Log.i(TAG, "getFrom:" + r.getFrom());
}
}
}
});
日志输出为:
09-02 18:08:25.070 23651-23651 I / RidesFragment:
dataSnapshot.getChildrenCount():1
09-02 18:08:25.070 23651-23651 I / RidesFragment:[{to = Hackerscher
Markt,userID = 0,时间= 1472831718565,定期= false,price = 0,
selectedUserID = 0,active = true,places = 1,来自= Hauptbahnhof Berlin,
MeetingPointDescription = blaues ei}]
public class Ride {
private String from;
private String to;
private long time;
private int places;
private String meetingPointDescription;
private boolean regularly;
private boolean active;
private float price;
private int userID;
private int chosenUserID;
public Ride() {
// Default constructor required for calls to DataSnapshot.getValue(Ride.class)
}
public Ride(String from, String to, long time, int places, String meetingPointDescription, boolean regularly,
boolean active, float price, int userID, int chosenUserID) {
this.from = from;
this.to = to;
this.time = time;
this.places = places;
this.meetingPointDescription = meetingPointDescription;
this.regularly = regularly;
this.active = active;
this.price = price;
this.userID = userID;
this.chosenUserID = chosenUserID;
}
// automatically generated getters and setters...
}
最佳答案
第三次我得到我自己的问题的答案:/
ArrayList<Ride> value = (ArrayList<Ride>) dataSnapshot.getValue();
必须替换为
GenericTypeIndicator<ArrayList<Ride>> t = new GenericTypeIndicator<ArrayList<Ride>>() {};
ArrayList<Ride> value = dataSnapshot.getValue(t);
一切都按预期进行。