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I don't get the constraint notice when using this approach:

import SwiftUI


struct ConstraintIssue: View {
var body: some View {
NavigationView {
Text("Detail View")
.toolbar(content: {
ToolbarItem(placement: .principal, content: {
Text("Detail View Title")
})
ToolbarItem(placement: .navigationBarTrailing, content: {
Button(action: {
print("Button Pressed")
}) {
Image(systemName: "ellipsis")
})
}
}
)
}
}
}

小开

I also have these warnings after updating to Xcode 12.3 today with this simple view but it looks normal with no bugs. guess that is a bug of new Xcode version.

struct ContentView: View {
var body: some View {
NavigationView {
Text("Hello World")
.navigationTitle("Hello World")
.toolbar {
ToolbarItem(placement: .navigationBarLeading) {
Button(action: {},
label: {
Image(systemName: "plus.circle")
})
}
ToolbarItem(placement: .navigationBarTrailing) {
Button(action: {},
label: {
Image(systemName: "plus.circle")
})
}
}
}
}
}

Here are the warnings

2020-12-16 14:25:05.897555+0800 TestingSwiftUI[76909:541649] [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:0x600002847020 'BIB_Trailing_CB_Leading' H:[_UIModernBarButton:0x7f7f7fc19680]-(6)-[_UIModernBarButton:0x7f7f8200ff20'HelloWorld']   (active)>",
"<NSLayoutConstraint:0x600002847070 'CB_Trailing_Trailing' _UIModernBarButton:0x7f7f8200ff20'HelloWorld'.trailing <= _UIButtonBarButton:0x7f7f7fc18740.trailing   (active)>",
"<NSLayoutConstraint:0x600002847de0 'UINav_static_button_horiz_position' _UIModernBarButton:0x7f7f7fc19680.leading == UILayoutGuide:0x6000032689a0'UIViewLayoutMarginsGuide'.leading   (active)>",
"<NSLayoutConstraint:0x600002847ed0 'UINavItemContentGuide-leading' H:[_UIButtonBarButton:0x7f7f7fc18740]-(0)-[UILayoutGuide:0x6000032688c0'UINavigationBarItemContentLayoutGuide']   (active)>",
"<NSLayoutConstraint:0x60000286a440 'UINavItemContentGuide-trailing' UILayoutGuide:0x6000032688c0'UINavigationBarItemContentLayoutGuide'.trailing == _UINavigationBarContentView:0x7f7f8200e2c0.trailing   (active)>",
"<NSLayoutConstraint:0x60000285c410 'UIView-Encapsulated-Layout-Width' _UINavigationBarContentView:0x7f7f8200e2c0.width == 0   (active)>",
"<NSLayoutConstraint:0x60000286a800 'UIView-leftMargin-guide-constraint' H:|-(0)-[UILayoutGuide:0x6000032689a0'UIViewLayoutMarginsGuide'](LTR)   (active, names: '|':_UINavigationBarContentView:0x7f7f8200e2c0 )>"
)


Will attempt to recover by breaking constraint
<NSLayoutConstraint:0x600002847020 'BIB_Trailing_CB_Leading' H:[_UIModernBarButton:0x7f7f7fc19680]-(6)-[_UIModernBarButton:0x7f7f8200ff20'HelloWorld']   (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.

when I delete

.navigationTitle("Hello World")

the warnings disappeared

so I'm gonna report this issue to Apple

this view looks normal

小开

NavigationBarTitle is deprecated from iOS 14.3 https://developer.apple.com/documentation/swiftui/view/navigationbartitle(_:displaymode:)-8buvp

You can use NavigationTitle and .navigationViewStyle(StackNavigationViewStyle())

import SwiftUI


struct HomeView: View {
var body: some View {
NavigationView {
Text("Text")
.navigationBarTitle("Hey there", displayMode: .inline)
}
.navigationViewStyle(StackNavigationViewStyle())
}
}

小开

I got the same warnings always, but everything works fine. Now like you said, I delete the .navigationtTitle(), and the warnings disappears, it looks like a bug .

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最佳答案

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())
}
}

The new way:

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

小开

a small note.. I am wrong or ADC code is wrong??

You can read:

.navigationBarTitle(Text("Today's Flavors", displayMode: .inline)

BUT is wrong: “Cannot infer contextual base in reference to member 'inline’”

They mis-placed a parenthesis:

Right code is:

.navigationBarTitle(Text("Today's Flavors"), displayMode: .inline)

complete code if You want to try...

import SwiftUI




struct ContentView: View {
let items = ["Chocolate", "Vanilla", "Strawberry", "Mint Chip",
"Pistachio"]
var body: some View {
NavigationView {
List(items, id: \.self) {
Text($0)
}
.navigationBarTitle(Text("Today's Flavors"), displayMode: .inline)
}
}
}


struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}

PS

in MARCH 2021 Apple has fixed.. but you can try copies around with fake code... for example here:

https://gist.github.com/erica/6941e2adfce75807bcd64550b3669c26

小开

It had nothing to do with NavigationBarTitle. .navigationTitle is not deprecated. Seems the whole issue is mainly with the new Xcode 12.4 update, even for simple code:

var body: some View {
NavigationView{
Text("Hopefully will work this time")
.navigationTitle("Error with constains")
}
}

adding .navigationViewStyle(StackNavigationViewStyle()) fixes problem

var body: some View {
NavigationView{
Text("Yes it does!")
.navigationTitle("Wow it works")
}
.navigationViewStyle(StackNavigationViewStyle())
}

小开

struct QuizView: View {
var body: some View {


NavigationView{
Text("Hello, world!")
.navigationBarTitle("Ripa", displayMode: .inline)
}
.navigationViewStyle(StackNavigationViewStyle()) /// add this line


}
}

小开

Just replace the .navigationBarTitle("string") with .navigationTitle("string") is fine. And add .navigationViewStyle.

小开

Unfortunately, a lot of the solutions advising the use of StackNavigationViewStyle() won't work if you're building an iPad app which uses the sidebar.

Digging a little deeper, if you add this line:

UserDefaults.standard.set(false, forKey: "_UIConstraintBasedLayoutLogUnsatisfiable")

in either your AppDelegate or App instance will suppress the errors. You'll get a one line warning that you've disabled it. I believe this is acceptable, since by using SwiftUI we shouldn't have to worry about LayoutConstraints and hopefully Apple will suppress this stuff by default since we're using SwiftUI.

see this SO answer for more info

小开

All of the above answers are not quite complete, so I would like to add, because I have studied this question for a long time and this is what I came to. I think it will be useful:

One of the interesting things about Navigation View is how it also performs the split-screen function on large devices-usually iPhones and large iPads.

var body: some View {
NavigationView {
Text("Primary")
}
}

If you rotate to landscape orientation (Cmd + ->) of the iPhone 11 ProMax, you will see that the text view disappears.

SwiftUI automatically considers landscape navigation views and shows DetailView instead of main ("Primary").

You can solve the problem the way SwiftUI expects by providing two views inside your NavigationView, for instance:

var body: some View {
NavigationView {
Text("Primary")
Text("Secondary")
}
}

Since I have little reputation, I can only post a photo with a link (If my post was useful, please rate it): enter image description here

This is why the error "Unable to simultaneously satisfy constraints" is thrown if we add. navigation Bar Title(Text ("Today's Flavors"), displayMode:. inline)

Therefore, the solution is as follows:

Add a second view to the Navigation View

Here, when you rotate the screen, screen # 2 - Text("Secondary") will be displayed.

    var body: some View {
NavigationView {
Text("Primary")
Text("Secondary")
.navigationBarTitle(Text("Today's Flavors"), displayMode: .inline)
}
}

Modifier .navigationViewStyle(StackNavigationViewStyle())

However, if you want to explicitly specify that the first screen (Text("Primary")) is always displayed when you rotate, then you need to add the .navigationViewStyle(StackNavigationViewStyle) modifier()) , which allows you to always switch to Text ("Primary"), regardless of the screen.

var body: some View {
NavigationView {
Text("Primary")
Text("Secondary")
.navigationBarTitle(Text("Today's Flavors"), displayMode: .inline)
}
.navigationViewStyle(StackNavigationViewStyle())

Also, you can read, more about NavigationView here

小开

Xcode 13.0 Beta 1

This is still causing a contraint error unless you add the StackNavigationViewStyle modifier.

However, the documentation for StackNavigationViewStyle states:

Do not use this type directly. Instead, use stack.

var body: some View {
NavigationView {
Text("Text")
.navigationTitle("Title")
}
.navigationViewStyle(.stack)
}

小开

I was running into similar issues with this:

var body: some View {
NavigationView {
List {
NavigationLink(destination: SettingsView()) {
Text("Settings")
}


NavigationLink(destination: SettingsView()) {
Text("Restore Purchases")
}
                

}.navigationTitle(Text("More"))
}
}

Bizarrely, moving the navigationTitle inside to anything inside the List fixes it e.g:

var body: some View {
NavigationView {
List {
NavigationLink(destination: SettingsView()) {
Text("Settings")
}


NavigationLink(destination: SettingsView()) {
Text("Restore Purchases")
}
.navigationTitle(Text("More"))
}
}
}

I was previously under the impression that navigationTitle could be attached to any view as long as it was contained inside the NavigationView but apparently not. I have other instances of navigationTitle() being attached to the List view in my app working fine so no idea why this particular view was causing an error.