尝试在SwiftUI中添加一个全屏活动指示器。
我可以在视图协议中使用.overlay(overlay:)函数。
有了这个，我可以做任何视图叠加，但我找不到iOS默认风格UIActivityIndicatorView等效的SwiftUI。
如何使用SwiftUI创建默认样式微调器?
注意:这不是关于在UIKit框架中添加活动指示器。
当前回答
如果你想要一个swift-ui风格的解决方案，那么神奇的是:
import Foundation
import SwiftUI
struct ActivityIndicator: View {
@State private var isAnimating: Bool = false
var body: some View {
GeometryReader { (geometry: GeometryProxy) in
ForEach(0..<5) { index in
Group {
Circle()
.frame(width: geometry.size.width / 5, height: geometry.size.height / 5)
.scaleEffect(calcScale(index: index))
.offset(y: calcYOffset(geometry))
}.frame(width: geometry.size.width, height: geometry.size.height)
.rotationEffect(!self.isAnimating ? .degrees(0) : .degrees(360))
.animation(Animation
.timingCurve(0.5, 0.15 + Double(index) / 5, 0.25, 1, duration: 1.5)
.repeatForever(autoreverses: false))
}
}
.aspectRatio(1, contentMode: .fit)
.onAppear {
self.isAnimating = true
}
}
func calcScale(index: Int) -> CGFloat {
return (!isAnimating ? 1 - CGFloat(Float(index)) / 5 : 0.2 + CGFloat(index) / 5)
}
func calcYOffset(_ geometry: GeometryProxy) -> CGFloat {
return geometry.size.width / 10 - geometry.size.height / 2
}
}
简单地使用:
ActivityIndicator()
.frame(width: 50, height: 50)
希望能有所帮助!
使用示例:
ActivityIndicator()
.frame(width: 200, height: 200)
.foregroundColor(.orange)
其他回答
SwiftUI中的活动指标
import SwiftUI
struct Indicator: View {
@State var animateTrimPath = false
@State var rotaeInfinity = false
var body: some View {
ZStack {
Color.black
.edgesIgnoringSafeArea(.all)
ZStack {
Path { path in
path.addLines([
.init(x: 2, y: 1),
.init(x: 1, y: 0),
.init(x: 0, y: 1),
.init(x: 1, y: 2),
.init(x: 3, y: 0),
.init(x: 4, y: 1),
.init(x: 3, y: 2),
.init(x: 2, y: 1)
])
}
.trim(from: animateTrimPath ? 1/0.99 : 0, to: animateTrimPath ? 1/0.99 : 1)
.scale(50, anchor: .topLeading)
.stroke(Color.yellow, lineWidth: 20)
.offset(x: 110, y: 350)
.animation(Animation.easeInOut(duration: 1.5).repeatForever(autoreverses: true))
.onAppear() {
self.animateTrimPath.toggle()
}
}
.rotationEffect(.degrees(rotaeInfinity ? 0 : -360))
.scaleEffect(0.3, anchor: .center)
.animation(Animation.easeInOut(duration: 1.5)
.repeatForever(autoreverses: false))
.onAppear(){
self.rotaeInfinity.toggle()
}
}
}
}
struct Indicator_Previews: PreviewProvider {
static var previews: some View {
Indicator()
}
}
自定义指标
虽然苹果现在支持原生活动指示器从SwiftUI 2.0，你可以简单地实现自己的动画。这些都是SwiftUI 1.0所支持的。此外，它还在小部件方面发挥作用。
Arcs
struct Arcs: View {
@Binding var isAnimating: Bool
let count: UInt
let width: CGFloat
let spacing: CGFloat
var body: some View {
GeometryReader { geometry in
ForEach(0..<Int(count)) { index in
item(forIndex: index, in: geometry.size)
.rotationEffect(isAnimating ? .degrees(360) : .degrees(0))
.animation(
Animation.default
.speed(Double.random(in: 0.2...0.5))
.repeatCount(isAnimating ? .max : 1, autoreverses: false)
)
}
}
.aspectRatio(contentMode: .fit)
}
private func item(forIndex index: Int, in geometrySize: CGSize) -> some View {
Group { () -> Path in
var p = Path()
p.addArc(center: CGPoint(x: geometrySize.width/2, y: geometrySize.height/2),
radius: geometrySize.width/2 - width/2 - CGFloat(index) * (width + spacing),
startAngle: .degrees(0),
endAngle: .degrees(Double(Int.random(in: 120...300))),
clockwise: true)
return p.strokedPath(.init(lineWidth: width))
}
.frame(width: geometrySize.width, height: geometrySize.height)
}
}
不同变奏的演示
Bars
struct Bars: View {
@Binding var isAnimating: Bool
let count: UInt
let spacing: CGFloat
let cornerRadius: CGFloat
let scaleRange: ClosedRange<Double>
let opacityRange: ClosedRange<Double>
var body: some View {
GeometryReader { geometry in
ForEach(0..<Int(count)) { index in
item(forIndex: index, in: geometry.size)
}
}
.aspectRatio(contentMode: .fit)
}
private var scale: CGFloat { CGFloat(isAnimating ? scaleRange.lowerBound : scaleRange.upperBound) }
private var opacity: Double { isAnimating ? opacityRange.lowerBound : opacityRange.upperBound }
private func size(count: UInt, geometry: CGSize) -> CGFloat {
(geometry.width/CGFloat(count)) - (spacing-2)
}
private func item(forIndex index: Int, in geometrySize: CGSize) -> some View {
RoundedRectangle(cornerRadius: cornerRadius, style: .continuous)
.frame(width: size(count: count, geometry: geometrySize), height: geometrySize.height)
.scaleEffect(x: 1, y: scale, anchor: .center)
.opacity(opacity)
.animation(
Animation
.default
.repeatCount(isAnimating ? .max : 1, autoreverses: true)
.delay(Double(index) / Double(count) / 2)
)
.offset(x: CGFloat(index) * (size(count: count, geometry: geometrySize) + spacing))
}
}
不同变奏的演示
眼罩
struct Blinking: View {
@Binding var isAnimating: Bool
let count: UInt
let size: CGFloat
var body: some View {
GeometryReader { geometry in
ForEach(0..<Int(count)) { index in
item(forIndex: index, in: geometry.size)
.frame(width: geometry.size.width, height: geometry.size.height)
}
}
.aspectRatio(contentMode: .fit)
}
private func item(forIndex index: Int, in geometrySize: CGSize) -> some View {
let angle = 2 * CGFloat.pi / CGFloat(count) * CGFloat(index)
let x = (geometrySize.width/2 - size/2) * cos(angle)
let y = (geometrySize.height/2 - size/2) * sin(angle)
return Circle()
.frame(width: size, height: size)
.scaleEffect(isAnimating ? 0.5 : 1)
.opacity(isAnimating ? 0.25 : 1)
.animation(
Animation
.default
.repeatCount(isAnimating ? .max : 1, autoreverses: true)
.delay(Double(index) / Double(count) / 2)
)
.offset(x: x, y: y)
}
}
不同变奏的演示
为了防止代码墙，您可以在git托管的这个repo中找到更优雅的指示器。
注意，所有这些动画都有一个必须切换才能运行的Binding。
我已经使用AppKit和SwiftUI修改了Matteo Pacini的macOS答案。这允许你在SwiftUI中使用NSProgressIndicator，同时保留macOS 10.15的功能。
import AppKit
import SwiftUI
struct ActivityIndicator: NSViewRepresentable {
@Binding var isAnimating: Bool
let style: NSProgressIndicator.Style
func makeNSView(context: NSViewRepresentableContext<ActivityIndicator>) -> NSProgressIndicator {
let progressIndicator = NSProgressIndicator()
progressIndicator.style = self.style
return progressIndicator
}
func updateNSView(_ nsView: NSProgressIndicator, context: NSViewRepresentableContext<ActivityIndicator>) {
isAnimating ? nsView.startAnimation(nil) : nsView.stopAnimation(nil)
}
}
用法如下:
ActivityIndicator(isAnimating: .constant(true), style: .spinning)
struct ContentView: View {
@State private var isCircleRotating = true
@State private var animateStart = false
@State private var animateEnd = true
var body: some View {
ZStack {
Circle()
.stroke(lineWidth: 10)
.fill(Color.init(red: 0.96, green: 0.96, blue: 0.96))
.frame(width: 150, height: 150)
Circle()
.trim(from: animateStart ? 1/3 : 1/9, to: animateEnd ? 2/5 : 1)
.stroke(lineWidth: 10)
.rotationEffect(.degrees(isCircleRotating ? 360 : 0))
.frame(width: 150, height: 150)
.foregroundColor(Color.blue)
.onAppear() {
withAnimation(Animation
.linear(duration: 1)
.repeatForever(autoreverses: false)) {
self.isCircleRotating.toggle()
}
withAnimation(Animation
.linear(duration: 1)
.delay(0.5)
.repeatForever(autoreverses: true)) {
self.animateStart.toggle()
}
withAnimation(Animation
.linear(duration: 1)
.delay(1)
.repeatForever(autoreverses: true)) {
self.animateEnd.toggle()
}
}
}
}
}
如果你想要一个swift-ui风格的解决方案，那么神奇的是:
import Foundation
import SwiftUI
struct ActivityIndicator: View {
@State private var isAnimating: Bool = false
var body: some View {
GeometryReader { (geometry: GeometryProxy) in
ForEach(0..<5) { index in
Group {
Circle()
.frame(width: geometry.size.width / 5, height: geometry.size.height / 5)
.scaleEffect(calcScale(index: index))
.offset(y: calcYOffset(geometry))
}.frame(width: geometry.size.width, height: geometry.size.height)
.rotationEffect(!self.isAnimating ? .degrees(0) : .degrees(360))
.animation(Animation
.timingCurve(0.5, 0.15 + Double(index) / 5, 0.25, 1, duration: 1.5)
.repeatForever(autoreverses: false))
}
}
.aspectRatio(1, contentMode: .fit)
.onAppear {
self.isAnimating = true
}
}
func calcScale(index: Int) -> CGFloat {
return (!isAnimating ? 1 - CGFloat(Float(index)) / 5 : 0.2 + CGFloat(index) / 5)
}
func calcYOffset(_ geometry: GeometryProxy) -> CGFloat {
return geometry.size.width / 10 - geometry.size.height / 2
}
}
简单地使用:
ActivityIndicator()
.frame(width: 50, height: 50)
希望能有所帮助!
使用示例:
ActivityIndicator()
.frame(width: 200, height: 200)
.foregroundColor(.orange)
