使用GeometryReader而不修改视图

Question

我在这里尝试使用GeometryReader来构建基于可用大小的视图，但是因为这个视图是嵌入到一个带有填充的父视图中，所以它不能正确绘制。我从other SO answers那里了解到，有些人说要将GeometryReader用作.overlay或.background，但我在这里想不出这样做的方法：

 var body: some View {
        GeometryReader { geometry in
            HStack(alignment: .bottom, spacing: 5) {
                ForEach(dataStore.sleepOrAwakeSpans) { sleepOrAwakeSpan in
                    VStack {
                        RoundedRectangle(cornerRadius: 5.0)
                            .frame(width: geometry.size.width * CGFloat((sleepOrAwakeSpan.endTime.timeIntervalSince(sleepOrAwakeSpan.startTime) / athlyticDataStore.sleepOrAwakeSpans.map { $0.endTime.timeIntervalSince($0.startTime) }.reduce(0, +))), height: 25)
                            .foregroundColor(sleepOrAwakeSpan.asleep == false ? TrackerConstants.scaleLevel6Color : TrackerConstants.scaleLevel2Color)
                    }
                }
            }
        }
    }

Answer 1

请尝试以下操作

var body: some View {
    Color.clear.overlay(     // << consumes available space of parent
        GeometryReader { geometry in
            HStack(alignment: .bottom, spacing: 5) {
                ForEach(dataStore.sleepOrAwakeSpans) { sleepOrAwakeSpan in
                    VStack {
                        RoundedRectangle(cornerRadius: 5.0)
                            .frame(width: geometry.size.width * CGFloat((sleepOrAwakeSpan.endTime.timeIntervalSince(sleepOrAwakeSpan.startTime) / athlyticDataStore.sleepOrAwakeSpans.map { $0.endTime.timeIntervalSince($0.startTime) }.reduce(0, +))), height: 25)
                            .foregroundColor(sleepOrAwakeSpan.asleep == false ? TrackerConstants.scaleLevel6Color : TrackerConstants.scaleLevel2Color)
                    }
                }
            }
        })     // end of overlay
}