在iOS 14小部件上渲染图像 [英] Render Images on iOS 14 Widgets

问题描述

我正在开发iOS 14 Widget扩展程序.

I'm developing a iOS 14 Widget extension.

我有3张图像要循环显示，并创建一个时间轴以显示这些图像.

I have 3 images to show in loop and creating a Timeline to show those images.

func getTimeline(in context: Context, completion: @escaping (Timeline<Entry>) -> ()) {
    var entries: [ImageEntry] = []
    let currentDate = Date()
    
    for i in 1 ..< 4 {
        let imageNumber = String(i)
        let currentImage = "image_" + imageNumber
        let entry = ImageEntry(date: currentDate,image: currentImage)
        entries.append(entry)
    }

    let nextUpdateDate = Calendar.current.date(byAdding: .minute, value: 5, to: currentDate)!
    let timeline = Timeline(entries: entries, policy: .after(nextUpdateDate))

    completion(timeline)
}


struct WidgetModuleEntryView : View {
var entry: Provider.Entry

var body: some View {
    Image(entry.image)
        .resizable()
        .scaledToFill()
    }
}

第一个图像始终呈现，但后一个图像不呈现.

First image always rendering but subsequent images are not.

可能是什么问题?

推荐答案

构造时间表需要为每个条目指定明确的条目日期.该策略参数用于重新创建下一个时间轴.

Constucting timeline you need to specify explicit entry date for each entry. The policy parameter is for recreating next timeline.

所以您的getTimeline应该看起来像

func getTimeline(in context: Context, completion: @escaping (Timeline<Entry>) -> ()) {
    var entries: [ImageEntry] = []
    let currentDate = Date()

    for i in 1 ..< 4 {
        let imageNumber = String(i)
        let currentImage = "image_" + imageNumber
        let entryDate = Calendar.current.date(byAdding: .minute, value: (i-1)*5, to: currentDate)!
        let entry = ImageEntry(date: entryDate, image: currentImage)
        entries.append(entry)
    }

    let timeline = Timeline(entries: entries, policy: .atEnd)
    completion(timeline)
}

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