协议扩展不适用于RCT_EXPORT_VIEW_PROPERTY？

Question

我有一个部分基类rnchartbaseview（协议和扩展），以及诸如rnlinechartview，rnbarchartview等的一堆子类等。

rnchartbaseview.swift

 protocol RNChartBaseView {
      associatedtype T: ChartViewBase;
      associatedtype U: ChartDataEntryBase;
      var chart: T { get }
      func createEntries(_ data: NSDictionary) -> [U];
      func setData(_ data: NSDictionary);
 }
 extension RNChartBaseView  {
       func setData(_ data: NSDictionary) {
           
           let chartData = createEntries(data);
           chart.data = chartData;
       }
 }

rnlinechartview.swift

 class RNLineChartView : UIView, RNChartBaseView{
      let _chart:LineChartView;
     
      var chart: LineChartView {
         return _chart
      }
      override init(frame: CGRect) {
         self._chart = LineChartView(frame: frame);
         super.init(frame: frame);
         self.addSubview(_chart);
      }
      func createEntries(_ data: NSDictionary) -> [LineDataEntry] {
        // ....... convert to LineDataEntry array.
        return entries;
      }
 }

rnlinechartviewmanagerswift.swift

 @objc(RNLineChartViewManagerSwift)
 class RNLineChartViewManagerSwift: RCTViewManager {
   override func view() -> UIView! {
     let ins = RNLineChartView()
     return ins;
   }       
 }

rnlinechartviewmanager.m

 #import "React/RCTViewManager.h"
 @interface RCT_EXTERN_MODULE(RNLineChartViewManagerSwift, RCTViewManager)
 RCT_EXPORT_VIEW_PROPERTY(data, NSDictionary)
 @end

但我得到

[reactNativeCharts.RNLineChartView setData:]: unrecognized selector sent to instance 0x7fdf60e04510'

如果我将setData从扩展名复制到rnlinechartview.swift，则每件事都很好。

问题在哪里？

更新

似乎是必需的。

但是以下代码不是优雅的，如何以正确的方式写入？

rnchartbaseViewClass

class RNChartBaseViewClass: UIView, RNChartBaseView {
    
    var chart: ChartViewBase {
        fatalError("subclass should override this function.")
    };
    
    override init(frame: CGRect) {
        fatalError("subclass should override this function.")
    }
    func createEntries(_ data: NSDictionary) -> [BaseChartDataEntry] {
        fatalError("subclass should override this function.") 
    }

    func setData(_ data: NSDictionary) {
        let chartData = createEntries(data);
        chart.data = chartData;
    }
}

rnlinechartview.swift

class RNLineChartView : RNChartBaseViewClass{
      var _chart : LineChartView;
      override var chart: LineChartView {
         return _chart
      }
      override init(frame: CGRect) {
         self._chart = LineChartView(frame: frame);
         super.init(frame: frame);
         self.addSubview(_chart);
      }
      override func createEntries(_ data: NSDictionary) -> [BaseChartDataEntry] { 
           // I have to use [BaseChartDataEntry] here as return type to pass compile,
           //  although it actually is [LineDataEntry],  it may cause further problems, e.g. 
        // ....... convert to LineDataEntry array.
        return entries;
      }
 }

更新

终于使用了扩展和子类的组合。

模板代码正在扩展。在rnchartbaseviewClass

中

class RNChartViewBaseClass: UIView, RNChartViewBase {
      ......
      func setData(_ data: NSDictionary) {
          (self as RNChartViewBase).setData(data)
      }
}

Answer 1

问题在于，Objective-C在React-Native使用Objection-C的消息传递机制（OBJC_MSGSEND）的同时，对协议扩展一无所知。您不能使用协议扩展来注入一种方法，以便对Objective-C的消息传递机制可见。

而不是协议，您可以在那里创建一个Uiview的子类，并在此处声明SetData方法。