ios - 我怎样才能简单地将 View 转换为 SwiftUI View ？

Question

我想通过 SwiftUI 和 Timer 实现一个简单的 View 转换。我有一个主要 View ，它是内容 View 。如果我从 View 中调用 func FireTimer() ，该函数将触发计时器。然后 5 秒后，我将进行 View 转换。

我尝试了 NavigationLink，但它有一个按钮。计时器无法按下按钮，所以现在我很困惑。我将在下面显示我的代码。

TimerFire.swift

import Foundation
import UIKit
import SwiftUI

let TIME_MOVENEXT = 5
var timerCount : Int = 0

class TimerFire : ObservableObject{
    var workingTimer = Timer()

    @objc func FireTimer() {
        print("FireTimer")
        workingTimer = Timer.scheduledTimer(timeInterval: 1,     
            target: self,                                        
            selector: #selector(TimerFire.timerUpdate),      
            userInfo: nil,                                   
            repeats: true)                                   
    }

    @objc func timerUpdate(timeCount: Int) {
        timerCount += 1
        let timerText = "timerCount:\(timerCount)"
        print(timerText)

        if timerCount == TIME_MOVENEXT {
            print("timerCount == TIME_MOVENEXT")

            workingTimer.invalidate()
            print("workingTimer.invalidate()")
            timerCount = 0

            //
            //want to have a transition to SecondView here
            //
        }
    }
}

ContentView.swift

import SwiftUI

struct ContentView: View {
    var body: some View {
        Button(action: {
            // What to perform
            let timerFire = TimerFire()
            timerFire.FireTimer()
        }) {
            // How the button looks like
            Text("Fire timer")
        }
    }
}

SecondView.swift

import Foundation
import SwiftUI

struct SecondView: View {
    var body: some View {
        Text("Second World")
    }
}

我怎样才能简单地显示这个SecondView？

Answer 1

好的，如果您想在第一个屏幕上不使用 NavigationView (出于任何原因)执行此操作，这里有一种基于两个 View 之间转换的可能方法。

注意:预览版对过渡的支持有限，因此请在模拟器和真实设备上进行测试

这是一个演示，它的外观(初始白屏只是模拟器启动)

这是单个测试模块:

import SwiftUI
import UIKit

let TIME_MOVENEXT = 5
var timerCount : Int = 0

class TimerFire : ObservableObject{
    var workingTimer = Timer()
    @Published var completed = false

    @objc func FireTimer() {
        print("FireTimer")
        workingTimer = Timer.scheduledTimer(timeInterval: 1,
            target: self,
            selector: #selector(TimerFire.timerUpdate),
            userInfo: nil,
            repeats: true)
    }

    @objc func timerUpdate(timeCount: Int) {
        timerCount += 1
        let timerText = "timerCount:\(timerCount)"
        print(timerText)

        if timerCount == TIME_MOVENEXT {
            print("timerCount == TIME_MOVENEXT")

            workingTimer.invalidate()
            print("workingTimer.invalidate()")
            timerCount = 0

            //
            //want to have a transition to SecondView here
            //
            self.completed = true
        }
    }
}

struct SecondView: View {
    var body: some View {
        Text("Second World")
    }
}

struct TestTransitionByTimer: View {
    @ObservedObject var timer = TimerFire()

    @State var showDefault = true
    var body: some View {
        ZStack {
            Rectangle().fill(Color.clear) // << to make ZStack full-screen
            if showDefault {
                Rectangle().fill(Color.blue) // << just for demo
                    .overlay(Text("Hello, World!"))
                    .transition(.move(edge: .leading))
            }
            if !showDefault {
                Rectangle().fill(Color.red) // << just for demo
                    .overlay(SecondView())
                    .transition(.move(edge: .trailing))
            }
        }
        .onAppear {
            self.timer.FireTimer()
        }
        .onReceive(timer.$completed, perform: { completed in
            withAnimation {
                self.showDefault = !completed
            }
        })
    }
}

struct TestTransitionByTimer_Previews: PreviewProvider {
    static var previews: some View {
        TestTransitionByTimer()
    }
}