React Native向Swift组件传回调属性崩溃，需用何种Objective-C类型？

问题详情 #

从React Native向自定义Swift组件传递回调作为属性，调用该回调时应用崩溃，报错信息如下：

No +[RCTConvert RCTResponseSenderBlock:] function found.

-[RCTComponentData createPropBlock:isShadowView:]
    RCTComponentData.m:258
-[RCTComponentData propBlockForKey:isShadowView:]
__37-[RCTComponentData setProps:forView:]_block_invoke
__NSDICTIONARY_IS_CALLING_OUT_TO_A_BLOCK__
-[__NSDictionaryM enumerateKeysAndObjectsWithOptions:usingBlock:]
-[RCTComponentData setProps:forView:]
__50-[RCTUIManager createView:viewName:rootTag:props:]_block_invoke.423
__44-[RCTUIManager flushUIBlocksWithCompletion:]_block_invoke
__44-[RCTUIManager flushUIBlocksWithCompletion:]_block_invoke.489
__RCTExecuteOnMainQueue_block_invoke
_dispatch_call_block_and_release
_dispatch_client_callout
_dispatch_main_queue_drain
_dispatch_main_queue_callback_4CF
__CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__
__CFRunLoopRun
CFRunLoopRunSpecific
GSEventRunModal
-[UIApplication _run]
UIApplicationMain
main
start_sim
0x0

当前使用的Objective-C声明文件：

@interface RCT_EXTERN_MODULE(AppleNativeWebViewManager, RCTViewManager)

RCT_EXPORT_VIEW_PROPERTY(urlToLoad, NSString)
RCT_EXPORT_VIEW_PROPERTY(matchedUrlCallback, RCTResponseSenderBlock)

@end

RCTResponseSenderBlock在原生模块中可正常使用，但作为原生视图的属性类型会导致崩溃，需替换为合适的类型。

解决方法 #

• 视图组件的回调属性不能用RCTResponseSenderBlock，需改用**RCTBubblingEventBlock或RCTDirectEventBlock**：
  • RCTBubblingEventBlock：支持事件冒泡，和React合成事件的冒泡机制一致
  • RCTDirectEventBlock：不支持冒泡，仅触发绑定的直接回调
• 修改Objective-C声明文件的属性类型：

  @interface RCT_EXTERN_MODULE(AppleNativeWebViewManager, RCTViewManager)
  
  RCT_EXPORT_VIEW_PROPERTY(urlToLoad, NSString)
  // 根据需求选择其中一种类型
  RCT_EXPORT_VIEW_PROPERTY(matchedUrlCallback, RCTBubblingEventBlock)
  
  @end
  

• 在Swift视图类中对应定义属性，并按要求调用：

  class AppleNativeWebView: UIView {
      var matchedUrlCallback: RCTBubblingEventBlock?
  
      func triggerMatchedUrlCallback(with url: String) {
          // 必须传入字典作为参数，无数据时传空字典[:]
          matchedUrlCallback?([
              "url": url
          ])
      }
  }
  

内容的提问来源于stack exchange，提问作者Mr. Robot