UIScrollView with fade effect with nativescript vuejs - nativescript

Question

I would like to know if it's possible to have UIScrollView with fade effect with nativescript please ?
For example : https://medium.com/#luisfmachado/uiscrollview-with-fade-effect-246e332e8b24
I read the documentation https://nativescript-vue.org/en/docs/elements/components/scroll-view/, but I don't found this information.
I would like this result for example :
Do you have an idea please ? Thank you
I have no idea how can I put the native code in my component
<template>
<ScrollView class="scroll" orientation="vertical" row="1" ref="scrollView">
<StackLayout marginLeft="10" marginRight="10" class="container-verses">
<StackLayout horizontalAlignment="center">
<Label textWrap="true" textAlignment="center" text="hello" color="#FFFFFF" fontSize="20"/>
...
<Label textWrap="true" textAlignment="center" text="hello" color="#FFFFFF" fontSize="20"/>
</StackLayout>
</StackLayout>
</ScrollView>
</template>
<script>
export default {
name : 'FadeScrollView',
computed: {},
methods : {
//
}
};
</script>
<style lang='scss' scoped>
</style>

Answer 1

Here is how you translate Swift into NativeScript
import { isIOS } from "#nativescript/core/platform";
import { ScrollView } from "#nativescript/core/ui/scroll-view";
let FadeScrollViewImpl;
if (isIOS) {
FadeScrollViewImpl = UIScrollView.extend({
fadePercentage: 0.2,
gradientLayer: CAGradientLayer.new(),
transparentColor: UIColor.clearColor.CGColor,
opaqueColor: UIColor.blackColor.CGColor,
topOpacity: () => {
const scrollViewHeight = this.frame.size.height;
const scrollContentSizeHeight = this.contentSize.height;
const scrollOffset = this.contentOffset.y;
const alpha = (scrollViewHeight >= scrollContentSizeHeight || scrollOffset <= 0) ? 1 : 0;
return UIColor.alloc().initWithWhiteAlpha(0, alpha).CGColor;
},
bottomOpacity: () => {
const scrollViewHeight = this.frame.size.height;
const scrollContentSizeHeight = this.contentSize.height;
const scrollOffset = this.contentOffset.y;
const alpha = (scrollViewHeight >= scrollContentSizeHeight || scrollOffset + scrollViewHeight >= scrollContentSizeHeight) ? 1 : 0
return UIColor.alloc().initWithWhiteAlpha(0, alpha).CGColor;
},
layoutSubviews() {
super.layoutSubviews()
this.delegate = this;
const maskLayer = CALayer.new();
maskLayer.frame = this.bounds;
this.gradientLayer.frame = CGRectMake(this.bounds.origin.x, 0, this.bounds.size.width, this.bounds.size.height);
this.gradientLayer.colors = [this.topOpacity, this.opaqueColor, this.opaqueColor, this.bottomOpacity];
this.gradientLayer.locations = [0, NSNumber.alloc().initWithFloat(this.fadePercentage), NSNumber.alloc().initWithFloat(1 - this.fadePercentage), 1];
maskLayer.addSublayer(this.gradientLayer);
this.layer.mask = maskLayer
},
scrollViewDidScroll(scrollView) {
this.gradientLayer.colors = [topOpacity, opaqueColor, opaqueColor, bottomOpacity];
}
});
}
export class FadeScrollView extends ScrollView {
createNativeView() {
if (isIOS) {
return FadeScrollViewImpl.new();
} else {
return super.createNativeView();
}
}
attachNative() {
if (!isIOS) {
super.attachNative();
}
}
}
Then you just have to register the element to start using it in template
Vue.registerElement('FadeScrollView', () => require('./fade-scrollView').FadeScrollView)
Playground Sample