NavigationBarTitle 导致 TabView 内部出错

Posted 2023-02-24

【中文标题】NavigationBarTitle 导致 TabView 内部出错

【英文标题】：NavigationBarTitle Causes Errors inside TabView

【发布时间】：2021-03-26 20:21:55

【问题描述】：

每当我将 NavigationView 嵌套在 TabView 中时，我就开始在控制台中收到一条错误消息，我收到以下错误。有解决办法吗？

struct ContentView: View 
    var body: some View 
        TabView
            NavigationView
                Text("Hello, world!")
            .padding()
                    .navigationBarTitle("Hello World")
            
            .tag(0)
            .tabItem 
                Text("Main")
            
        
            NavigationView
                Text("Hello, world!")
                    .padding()
                
            .tag(1)
            .tabItem 
                Text("Secondary")
            
            
        .edgesIgnoringSafeArea(.top)
        
        
    

我的控制台显示以下错误：

    2021-03-26 14:14:59.294828-0600 Playground[39119:2828740] [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:0x600001ae5fe0 'BIB_Trailing_CB_Leading' H:[_UIModernBarButton:0x7fdded4274f0]-(6)-[_UIModernBarButton:0x7fdded428920'Hello World']   (active)>",
    "<NSLayoutConstraint:0x600001ae6030 'CB_Trailing_Trailing' _UIModernBarButton:0x7fdded428920'Hello World'.trailing <= _UIButtonBarButton:0x7fdded7079f0.trailing   (active)>",
    "<NSLayoutConstraint:0x600001ae0230 'UINav_static_button_horiz_position' _UIModernBarButton:0x7fdded4274f0.leading == UILayoutGuide:0x6000000df1e0'UIViewLayoutMarginsGuide'.leading   (active)>",
    "<NSLayoutConstraint:0x600001ae94f0 'UINavItemContentGuide-leading' H:[_UIButtonBarButton:0x7fdded7079f0]-(0)-[UILayoutGuide:0x6000000df100'UINavigationBarItemContentLayoutGuide']   (active)>",
    "<NSLayoutConstraint:0x600001aee800 'UINavItemContentGuide-trailing' UILayoutGuide:0x6000000df100'UINavigationBarItemContentLayoutGuide'.trailing == _UINavigationBarContentView:0x7fdded4253a0.trailing   (active)>",
    "<NSLayoutConstraint:0x600001ae9cc0 'UIView-Encapsulated-Layout-Width' _UINavigationBarContentView:0x7fdded4253a0.width == 0   (active)>",
    "<NSLayoutConstraint:0x600001aeebc0 'UIView-leftMargin-guide-constraint' H:|-(0)-[UILayoutGuide:0x6000000df1e0'UIViewLayoutMarginsGuide'](LTR)   (active, names: '|':_UINavigationBarContentView:0x7fdded4253a0 )>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x600001ae5fe0 'BIB_Trailing_CB_Leading' H:[_UIModernBarButton:0x7fdded4274f0]-(6)-[_UIModernBarButton:0x7fdded428920'Hello World']   (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.

【参考方案1】：

我在这里找到了答案：

SwiftUI NavigationView navigationBarTitle LayoutConstraints issue

我需要添加 .navigationViewStyle(StackNavigationViewStyle())

当我将代码更新为此时，错误消失了：

struct ContentView: View 
var body: some View 
    TabView
        NavigationView
            Text("Hello, world!")
        .padding()
                .navigationTitle("Hello World")
        
        .navigationViewStyle(StackNavigationViewStyle())
        .tag(0)
        .tabItem 
            Text("Main")
        
    
        NavigationView
            Text("Hello, world!")
                .padding()
            
        .tag(1)
        .tabItem 
            Text("Secondary")
        
        
    .edgesIgnoringSafeArea(.top)