¿Cómo se traduce un puente OBJC JS?

Question

¿Cómo se traduce el marco Javascriptore, los objetos de JavaScript en objetos de objetivos y viceversa?¿El puente usa el mismo protocolo binario para comunicarse para ambos idiomas de destino?

Answer 1

El marco OBJETIVO-C introducido con IOS7 hace todo el levantamiento pesado para usted. No necesita pensar en los objetos como el mismo binario, sino que se interpreta de manera diferente: el marco realiza una copia cuando se convierte entre objc y javascript.

de jsvalue.h:

// Conversion between Objective-C and JavaScript types.
//
// When converting between JavaScript values and Objective-C objects a copy is
// performed. Values of types listed below are copied to the corresponding
// types on conversion in each direction. For NSDictionaries, entries in the
// dictionary that are keyed by strings are copied onto a JavaScript object.
// For dictionaries and arrays, conversion is recursive, with the same object
// conversion being applied to all entries in the collection.

  Objective-C type  |   JavaScript type
--------------------+---------------------
        nil         |     undefined
       NSNull       |        null
      NSString      |       string
      NSNumber      |   number, boolean
    NSDictionary    |   Object object
      NSArray       |    Array object
       NSDate       |     Date object
      NSBlock *     |   Function object *
         id **      |   Wrapper object **
       Class ***    | Constructor object ***

* Instances of NSBlock with supported arguments types will be presented to
JavaScript as a callable Function object. For more information on supported
argument types see JSExport.h. If a JavaScript Function originating from an
Objective-C block is converted back to an Objective-C object the block will
be returned. All other JavaScript functions will be converted in the same
manner as a JavaScript object of type Object.

** For Objective-C instances that do not derive from the set of types listed
above, a wrapper object to provide a retaining handle to the Objective-C
instance from JavaScript. For more information on these wrapper objects, see
JSExport.h. When a JavaScript wrapper object is converted back to Objective-C
the Objective-C instance being retained by the wrapper is returned.

*** For Objective-C Class objects a constructor object containing exported
class methods will be returned. See JSExport.h for more information on
constructor objects.

Por ejemplo (para tipos simples):

NSString *myString = [javascriptContext[@"myJSVar"] toString];

y

javascriptContext[@"myJSVar"] = myString;

O para un objeto más complejo, use el protocolo JSEXPORT:

@protocol MyPointExports <JSExport>
@property double x;
@property double y;
@end

@interface MyPoint : NSObject <MyPointExports>
// Put methods and properties not visible to JavaScript code here.
@end

...

javascriptContext[@"MyPoint"] = [MyPoint class]; // Define the class in Javascript

luego

MyPoint *p = [javascriptContext[@"myJSPointVar"] toObject];

y

javascriptContext[@"myJSPointVar"] = p;

Para cada propiedad declarada en el protocolo, el marco construirá JS Getter / Setters, por lo que dentro de Javascript, puede hacer:

myJSPointVar.x = 10;

Para aquellos lectores que buscan una introducción al marco de JavascriptCore, consulte la sesión 2013 WWDC Video / PDF "integrar Javascript en aplicaciones nativas" Sesión en la red de desarrolladores de Apple: https://developer.apple.com/videos/wwdc/2013/?id=615

Answer 2

Eche un vistazo a esta clase: NSJSOonserialization.