SwiftUI NavigationView navigationBarTitle LayoutConstraints问题 [英] SwiftUI NavigationView navigationBarTitle LayoutConstraints issue

问题描述

这可能与最近发布的XCode的新版本(12.3)有关，但是我有一个非常简单的SwiftUI视图:

This is maybe related to the new (12.3) version of XCode that came out recently but I have a very simple SwiftUI View:

import SwiftUI

struct HomeView: View {
    var body: some View {
        NavigationView {
            Text("Text")
                .navigationBarTitle("My Title")
        }
    }
}

我在控制台中收到此警告:

And I'm getting this warning in the console:

2020-12-15 18:25:06.506062-0800 Shopmatic[46177:9585655] [LayoutConstraints] Unable to simultaneously satisfy constraints.
    Probably at least one of the constraints in the following list is one you don't want. 
    Try this: 
        (1) look at each constraint and try to figure out which you don't expect; 
        (2) find the code that added the unwanted constraint or constraints and fix it. 
(
    "<NSLayoutConstraint:0x600003636d00 'BIB_Trailing_CB_Leading' H:[_UIModernBarButton:0x7faf15d0dc30]-(6)-[_UIModernBarButton:0x7faf15c17500'Your Lists']   (active)>",
    "<NSLayoutConstraint:0x600003636d50 'CB_Trailing_Trailing' _UIModernBarButton:0x7faf15c17500'Your Lists'.trailing <= _UIButtonBarButton:0x7faf15c16140.trailing   (active)>",
    "<NSLayoutConstraint:0x600003631e50 'UINav_static_button_horiz_position' _UIModernBarButton:0x7faf15d0dc30.leading == UILayoutGuide:0x600002c18ee0'UIViewLayoutMarginsGuide'.leading   (active)>",
    "<NSLayoutConstraint:0x600003631ea0 'UINavItemContentGuide-leading' H:[_UIButtonBarButton:0x7faf15c16140]-(0)-[UILayoutGuide:0x600002c18e00'UINavigationBarItemContentLayoutGuide']   (active)>",
    "<NSLayoutConstraint:0x600003617160 'UINavItemContentGuide-trailing' UILayoutGuide:0x600002c18e00'UINavigationBarItemContentLayoutGuide'.trailing == _UINavigationBarContentView:0x7faf15e10000.trailing   (active)>",
    "<NSLayoutConstraint:0x600003632580 'UIView-Encapsulated-Layout-Width' _UINavigationBarContentView:0x7faf15e10000.width == 0   (active)>",
    "<NSLayoutConstraint:0x600003617520 'UIView-leftMargin-guide-constraint' H:|-(0)-[UILayoutGuide:0x600002c18ee0'UIViewLayoutMarginsGuide'](LTR)   (active, names: '|':_UINavigationBarContentView:0x7faf15e10000 )>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x600003636d00 'BIB_Trailing_CB_Leading' H:[_UIModernBarButton:0x7faf15d0dc30]-(6)-[_UIModernBarButton:0x7faf15c17500'Your Lists']   (active)>

Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKitCore/UIView.h> may also be helpful.

这个简单的例子看起来不错，但是当我做一些更复杂的事情时:

This simple example looks fine but when I do something a bit more complex:

import SwiftUI

struct ListDetailView: View {
    var list: List
    
    var body: some View {
        NavigationView {
            Text("Detail View")
            .navigationBarTitle("Detail View Title")
            .navigationBarTitleDisplayMode(.large)
            .navigationBarItems(
                trailing:
                    Button(action: {
                        print("Button Pressed")
                    }) {
                        Image(systemName: "ellipsis")
                }
            )
        }
    }
}

导航标题区域的布局全部搞砸了:

The Navigation Title areas layout is all screwed up:

推荐答案

NavigationBarTitle .但是，如果您仍然希望使用它，请尝试添加 .navigationViewStyle(StackNavigationViewStyle()) 可以解决警告.

NavigationBarTitle is deprecated from iOS 14.3. However if you still wish to use it, try to add .navigationViewStyle(StackNavigationViewStyle()) on the navigationView that will fix the warning.

       struct ContentView: View {
        var body: some View {
            NavigationView {
                VStack {
                    Text("Hello, world!")
                        .padding()
                    Spacer()
                }
                .navigationBarTitle("Hey there", displayMode: .inline)
            }
            .navigationViewStyle(StackNavigationViewStyle())
        }
    }

新方法:

.navigationBarTitleDisplayMode(.inline)
.toolbar(content: {
     ToolbarItem(placement: .principal, content: {
     Text("Title")
  })})    

这篇关于SwiftUI NavigationView navigationBarTitle LayoutConstraints问题的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！