从Firebase实时数据库读取应用程序时崩溃

Question

 public  final  ArrayList<Parking> parkingArrayList=new ArrayList<Parking>();

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    FirebaseDatabase firebaseDatabase=FirebaseDatabase.getInstance();
    firebaseDatabase.setPersistenceEnabled(true);
    DatabaseReference databaseReference=firebaseDatabase.getReference();
    databaseReference.child("Parking").addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
           for(DataSnapshot dataSnapshot1:dataSnapshot.getChildren()){
            Parking p=dataSnapshot1.getValue(Parking.class);
           }
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });

public class  Parking implements  Comparable<Parking>,Parcelable {
public  String name;
public  String zone;
public String location;
public int capacity;
public double latitude;
public double longtitude;
int free=0;
int taken=0;
int id;
public  Parking(){
}
public Parking(int capacity,double latitude,String location, double longtitude,String name,String zone){
    this.capacity=capacity;
    this.location=location;
    this.name=name;
    this.zone=zone;
    this.latitude=latitude;
    this.longtitude=longtitude;
    this.taken=getTaken();
    this.free=getFree();
}

protected Parking(Parcel in) {
    name = in.readString();
    zone = in.readString();
    location = in.readString();
    capacity = in.readInt();
    latitude = in.readDouble();
    longtitude = in.readDouble();
    free = in.readInt();
    taken = in.readInt();
}

public static final Creator<Parking> CREATOR = new Creator<Parking>() {
    @Override
    public Parking createFromParcel(Parcel in) {
        return new Parking(in);
    }

    @Override
    public Parking[] newArray(int size) {
        return new Parking[size];
    }
};

public int getCapacity() {
    return capacity;
}

public int getFree() {
    return capacity-getTaken();
}

public int getTaken() {
    Random random=new Random();
    this.taken=random.nextInt(capacity+1);
    return  taken;
}

public  void  setFree(int taken){
    free=capacity-taken;
}
public void setTaken(int taken) {
    Random random=new Random();
    this.taken=random.nextInt(capacity+1);
}
public  double getLatitude(){
    return  latitude;
}
public  double getLongtidue(){
    return  longtitude;
}


@Override
public String toString() {
    return String.format("%s\t\tZone: %s\nlocation: %s\nCapacity: %d\t\tFree: %d",name,zone,location,capacity,getFree());
}


@Override
public int compareTo(@NonNull Parking parking) {
    return Integer.compare(parking.free,this.free);
}

@Override
public int describeContents() {
    return 0;
}

@Override
public void writeToParcel(Parcel parcel, int i) {
    parcel.writeInt(capacity);
    parcel.writeDouble(latitude);
    parcel.writeString(location);
    parcel.writeDouble(longtitude);
    parcel.writeString(name);
    parcel.writeString(zone);
   parcel.writeInt(getTaken());
    parcel.writeInt(getFree());
}