convert FIRDataSnapshot to custom type

问题:

I am trying to convert a FIRDataSnapshot to a custom type (i.e. I know that each child will have a Name, Number, and Email )

When I run the code below, a JSON tree with the each child containing a Name, Number, and Email prints to the console.

So I want to store the snapshot as a custom type "PersonInfo" that has each of those properties. That way I can alter this data within my app. I need to use the "PersonInfo" variable I store this data into in various parts of my app.

    ref.observeSingleEventOfType(.Value, withBlock: { (snapshot: FIRDataSnapshot) in

        print(snapshot)

    })

回答1:

You can define a custom class PersonInfo that will act as a model.

class PersonInfo: NSObject {
    var pName: String
    var pNumber :String
    var pEmail: String
    let ref: FIRDatabaseReference?

    init( name: String, number: String, email: String) {
        self.pName = name
        self.pNumber = number
        self.pEmail = email
        self.ref = nil
    }

    init(snapshot: FIRDataSnapshot) {
        pName = snapshot.value!["pName"] as! String
        pNumber = snapshot.value!["pNumber"] as! String
        pEmail = snapshot.value!["pEmail"] as! String
        ref = snapshot.ref
    }

    convenience override init() {
        self.init(name:"",number: "", email: "")
    }
}

And inside your observeSingleEventOfType when you have snapshot, you can iterate over its children and fetch each Person as:

for item in snapshot.children{
  var person = PersonInfo(snapshot:item);
  yourList.append(person);
}

So, you will have a list of PersonInfo model objects that you can access later.

回答2:

In objective c you can do so :

Header file :

#import <Foundation/Foundation.h>
#import <FirebaseDatabase/FirebaseDatabase.h>

@interface RTAObject : NSObject

@property (nonatomic) NSString pName;
@property (nonatomic) NSString * pNumber;
@property (nonatomic) NSString * pEmail;

-(id) init:(NSString) pName : (NSString*) name :(NSString*) pNumber :(NSString*) pEmail ;

@end

Source File :

#import "PersonInfo.h"

@implementation RTAObject


-(id)init:(FIRDataSnapshot *)snapshot {

     _pName = [snapshot valueForKey:@"name"];
     _pNumber = [snapshot valueForKey:@"number"];
     _pEmail = [snapshot valueForKey:@"email"];

     return self;
}

-(id) init:(NSString *)pName:(NSString *)pNumber :(NSString *)pEmail 
{

    _pName = pName;
    _pNumber = pNumber;
    _pEmail = pEmail;

    return self; 
}
@end