SwiftUI - 用自定义视图覆盖 TabView [英] SwiftUI - Overlay TabView with Custom View

问题描述

我有一个带有标签栏导航概念的应用.对于一个视图，我目前正在尝试实现一个标签栏覆盖，你们都知道 iOS 中的照片应用程序.选择图像时出现.见下文:

I'm having an app with a tab bar navigation concept. For one view I'm currently trying to implement a tab bar overlay that you all know from the Photos App in iOS. It appears when you select images. See below:

我试图在下面的代码片段中实现这种行为，但我有两个疑问:

I tried to implement this behavior in the below code snippet but I have two doubts:

• .overlay() 是正确的方法吗?我想将它与 State 结合起来，并相应地设置它以启用/禁用叠加层.
• 如果从编码的角度来看覆盖没问题，我将如何将其与底部对齐并注意调整大小以使其完全覆盖标签栏?

• is .overlay() the right way to do it? I wanted to combine it with a State and set it accordingly to enable / disable the overlay.
• if overlay is ok from a coding point of view, how would I align it to the bottom and take care of the sizing so that it exactly overlays the tab bar?

struct ContentView: View {
    var body: some View {
        TabView {
            
            NavigationView {
                Text("First Nav Page")
            }
            .tabItem {
                Image(systemName: "house")
                Text("Home")
                
            }.tag(0)
            
            NavigationView {
                Text("Second Nav Page")
            }
            .tabItem {
                Image(systemName: "gear")
                Text("Settings")
            }.tag(1)
            
            Text("No Nav Page")
                .tabItem{
                    Image(systemName: "plus")
                    Text("Test")
                }.tag(2)
            
        }.overlay(
            Rectangle()
                .foregroundColor(.red)
                .frame(width: 40, height: 40)
        )
    }
}

谢谢！

推荐答案

您正在寻找的是 Toolbar，而不是 TabBar.所以当用户在 EditMode 中改变时，你必须将 TabBar 改为 Toolbar.

What you are looking for is a Toolbar, not TabBar. So when the user changes in EditMode, you will have to change the TabBar into the Toolbar.

工具栏在 iOS 14 中可用，它在中心采用一个 ToolbarItem 作为状态，以及一个带有图标的前导项目.您应该构建一个将 TabBar 与 Toolbar 交换的函数.

The Toolbar is available in iOS 14 and takes a ToolbarItem for the Status in the center and a leading Item with your Icon. You should have to build a function which swapes your TabBar with the Toolbar.

以下是适用于您的情况的工具栏示例:

Here is a example of the Toolbar for your case:

struct ContentView: View {
    @State var isSelecting : Bool = false
    
    var body: some View {
        NavigationView {
            Text("Hello World")
                .toolbar {
                    ToolbarItem(placement: .bottomBar, content: {
                            Button(action: {
                                
                            }){
                                Image(systemName: "square.and.arrow.up")
                            }
                        })
                }
                .toolbar {
                    ToolbarItem(placement: .status, content: {
                            Text("Auswählen")
                                .fontWeight(.bold)
                    })
            }
        }
    }
}

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