How to call swift native function from react native? - objective-c

Question

I have a swift class, which i am exposing to react-native, inside that i have a function that is also exposed to react-native. Now when react native calls that function it does a lot of this internally, but after some point of time it returns an object.
Now it will call a specific function that will get the object. I cannot change the parameter to that function. But i have another function, to which i want to return to react native. How can i do it.
func AckCallback(response:APIResponse) -> Void
{
print(response)
}
for this function I cannot change the paremeter, becaused it had been used a lot of places, But I want to return that response from this function to react-native. If anybody know this issue, please let me know.
#objc func sendEvent(_ response: APIResponse, callback: (NSObject) -> ())
-> Void {
callback( [[
"responseCode" : "Working",
]] as NSObject)
}
I just want to know how to use this sendEvent inside the AckCallback, or is there any other way to send that **
response: APIResponse
**
to react-native.

Answer 1

For the first create Swift class (e.g YourModule.swift)
//
// YourModule.swift
//
#objc(YourModule)
class YourModule: NSObject {
#objc func callNativeEvent(callback:RCTResponseSenderBlock)
-> Void {
// Here you can do your work and pass an object to the callback function.
// You can save assign a `callback` to the class property (e.g self.eventCallback = callback)
// and invoke that self.eventCallback after the asynchronous code ol somewhere else
NSObject *obj = [[NSObject alloc] init]; // your object here
callback([NSNull(), obj]);
// or if you want to return an error
// callback(["Error calling NativeEvent", NSNull()]);
// I'm not sure that RCTResponseSenderBlock works the same as in previous react-native versions. Maybe now you can pass an Object instead of an Array.
}
}
Create a Bridge file (e.g. YourModuleBridge.m)
//
// YourModuleBridge.m
//
#import <Foundation/Foundation.h>
#import "UIKit/UIKit.h"
#import <React/RCTBridgeModule.h>
#interface RCT_EXTERN_MODULE(YourModule, NSObject)
RCT_EXTERN_METHOD(callNativeEvent:(RCTResponseSenderBlock)callback);
#end
Also, you need Bridging-Header file if it doesn't exist in your project.
//
// YourModule-Bridging-Header.h
//
#ifndef YourModule_Bridging_Header_h
#define YourModule_Bridging_Header_h
#if __has_include("RCTBridgeModule.h")
#import "RCTBridgeModule.h"
#else
#import <React/RCTBridgeModule.h>
#endif
#endif /* YourModule_Bridging_Header_h */
And from JS
import { NativeModules } from 'react-native';
const YourModule = NativeModules.YourModule;
...
YourModule.callNativeEvent((error, response) => {
console.log('Error', error, 'Response', response);
});

Answer 2

In iOS Project Create 2 Files
SwiftComponentManager.swift and SwiftComponentManager.m create these 2 files.
SwiftComponentManager.swift ->
#objc(SwiftComponentManager)
class SwiftComponentManager: NSObject {
#objc func passValueFromReact(_ value : String) {
debugPrint(" Print Here \(value)")
}
}
In SwiftComponentManager.m
#import <Foundation/Foundation.h>
#import "React/RCTBridgeModule.h"
#interface RCT_EXTERN_MODULE(SwiftComponentManager, NSObject)
RCT_EXTERN_METHOD(passValueFromReact:(NSString *)value) //Here exported your swift function for React Native
#end
Here start work in React-Native project
Now How will call this Swift function in React Native.
Import your SwiftComponent in React JS file
const { SwiftComponentManager } = NativeModules
Now call your function with value where you want in JS file
SwiftComponentManager.passValueFromReact("Hello World")