CODEWITHSUNDEEP
iosswiftreact-native
sin tribu
sin tribu

Reputation: 1180

React Native to Swift bridge - passing both a parameter and a callback

I am attempting to send base64 image string to swift and I would like the classification of the image returned to me in my call back. However, I can pass a string, and I can pass a callback individually with success, but when I add them together I am receiving:

Exception 'bothClassifyAndCallback: is not a recognized Objective-C method.

Here is my bridge.m - note methods classify and myCallback work just fine

#import "React/RCTBridgeModule.h"

@interface RCT_EXTERN_MODULE( ImageClassifier, NSObject )
    RCT_EXTERN_METHOD( classify: (NSString*)img  )
    RCT_EXTERN_METHOD( myCallback: (RCTResponseSenderBlock)callback )
    RCT_EXTERN_METHOD( bothClassifyAndCallback: (NSString*)img (RCTResponseSenderBlock)callback)
@end

Here is my bridge.swift file

import Foundation

@objc( ImageClassifier )
class ImageClassifier: NSObject {

  @objc
  func classify( _ img: String )  {
    print( img )
  }

  @objc 
  func myCallback( _ callback: RCTResponseSenderBlock ) {
      callback([ "From swift to js" ]) 
  }
  
  @objc 
  func bothClassifyAndCallback( _ img: String, _ callback: RCTResponseSenderBlock )  {
    print( img )
    return callback( [ "recieving and returning to js" ] )

  }

  @objc
  static func requiresMainQueueSetup() -> Bool {
      return true
  }

}

And here is my call in react native

class BridgeTest extends React.Component {
    constructor(){ 
        super()
        this.classifier = NativeModules.ImageClassifier 
    }
    onPress = () => {
        this.classifier.classify( "from js" )                                          // this works
        this.classifier.myCallback( ( arg ) => { console.log( "my arg is" + arg ) } ) // This works
        this.classifier.bothClassifyAndCallback( "argument", ( arg ) => { console.log( "my arg is " + arg ) })
     
}

render() {
    return( <Button title="bridge" onPress={this.onPress}></Button> )
}
export default BridgeTest
}

I suspect I am wrong here:

RCT_EXTERN_METHOD( bothClassifyAndCallback: (NSString*)img (RCTResponseSenderBlock)callback)

But after trying several variations I just can't get it to work. Thanks.

Upvotes: 4

Views: 2179

Answers (1)

Rajan Twanabashu
Rajan Twanabashu

Reputation: 4736

You need to make slight modification to bothClassifyAndCallback in both ImageClassifier and bridge.m for @objc declaration.

In ImageClassifier

@objc(bothClassifyAndCallback: resolver:) 
    
      func bothClassifyAndCallback( _ img: String, resolver callback: RCTResponseSenderBlock )  {
        print( img )
        return callback( [ "recieving and returning to js" ] )
    
      }

In Bridge.m

RCT_EXTERN_METHOD( bothClassifyAndCallback: (NSString*)img resolver: (RCTResponseSenderBlock)callback)

Upvotes: 1

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