如何在nativescript中从本机ios访问UIScrollview委托？

Iam使用nativescript angular应用程序运行android和ios应用程序。我想访问ios的scrollview代理，我从本机ios访问了scrollview代理，代码如下。但它不工作：

My scrollview委托实现类：

// import {Injectable, EventEmitter,Output} from "@angular/core";
@ObjCClass(UIScrollViewDelegate)
 export class FoodScrollDelegate extends NSObject implements UIScrollViewDelegate
{
    public static ObjCProtocols = [UIScrollViewDelegate];
    // @Output() yvalue:EventEmitter<any>=new EventEmitter();
    private _originalDelegate:UIScrollViewDelegate;
    public getY:Number=0;
     constructor()
     {
         super();
     }

    public static initWithOriginalDelegate(originalDelegate:UIScrollViewDelegate):FoodScrollDelegate{
        console.log("Called Method");
        let delegate=<FoodScrollDelegate>FoodScrollDelegate.new();
        delegate._originalDelegate=originalDelegate;
        return delegate;
    }


}

---

在i内部实现了委托方法。但是它正在工作

objc类

是

objc协议

的替代语法。你可能不需要同时做这两件事

加载事件后会附加默认代理，因此您的代理可能会再次被覆盖。您必须扩展ScrollView并覆盖

附件

方法

class MyScrollView extends ScrollView {
    protected attachNative() {
        (<any>ScrollView.prototype).attachNative.call(this);
        if (isIOS) {
            (<any>this)._delegate = FoodScrollDelegate.initWithOriginalDelegate((<any>this)._delegate);
            this.nativeViewProtected.delegate = (<any>this)._delegate;
        }
    }
}

现在，您应该能够在HTML中使用

MyScrollView

而不是

ScrollView

，这将覆盖默认委托。如果您想覆盖应用程序中使用的所有ScrollView的委托，只需在iOS上有条件地覆盖

ScrollView

的原型链即可

(<any>ScrollView.prototype).originalAttachNative = (<any>ScrollView.prototype).attachNative;
(<any>ScrollView.prototype).attachNative = function () {
    this.originalAttachNative();
    const newDelegate = FoodScrollDelegate.initWithOriginalDelegate(this._delegate);
    this._delegate = newDelegate;
    this.nativeViewProtected.delegate = newDelegate;
};

TS

onDragEnd(event) {
   console.log(event.decelerate);
}

---

委托方法仅在FoodScrollDelegate类中工作。我希望这些方法在html相关的组件类中工作。您所要做的就是触发事件并从组件中侦听它。好的，我将编辑我的问题，我在组件类中被称为委托方法的内容。Hai manoj我被提供了我的组件类请告诉我如何在类中调用委托方法？正如我前面提到的，您可以在ScrollView上触发一个事件，并从组件中侦听相同的事件。

registerElement("MyScrollView", () => MyScrollView);

(<any>ScrollView.prototype).originalAttachNative = (<any>ScrollView.prototype).attachNative;
(<any>ScrollView.prototype).attachNative = function () {
    this.originalAttachNative();
    const newDelegate = FoodScrollDelegate.initWithOriginalDelegate(this._delegate);
    this._delegate = newDelegate;
    this.nativeViewProtected.delegate = newDelegate;
};

   scrollViewDidEndDraggingWillDecelerate(scrollView: UIScrollView, decelerate: boolean) {
        const owner = (<WeakRef<ScrollView>>(<any>this._originalDelegate)._owner).get();
        if (owner) {
            owner.notify({
                object: owner,
                eventName: "dragEnd",
                decelerate: decelerate
            });
        }
    }

(dragEnd)="onDragEnd($event)"

onDragEnd(event) {
   console.log(event.decelerate);
}