ios 11 - UIBarButtonItem中的UIButton导致自动布局错误

Question

我有一个已知的问题,即将UIButton添加到UIBarButtonItem中.我已尝试添加自动布局约束,如stackoveflow中所示,但我收到如下所述的错误.

UIButton *sortButton = [UIButton buttonWithType:UIButtonTypeCustom];
[sortButton setFrame:CGRectMake(10, 0, 100, 30)];
[sortButton setTitle:@"Sort" forState:UIControlStateNormal];
[[sortButton titleLabel] setFont:[UIFont boldSystemFontOfSize:13]];
[sortButton setBackgroundImage:[UIImage imageNamed:@"backgroun-button.png"] forState:UIControlStateNormal];
[sortButton setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
[sortButton addTarget:self action:@selector(sortCollection:) forControlEvents:UIControlEventTouchUpInside];
[sortButton applyNavBarConstraints:100 height:30];

[self setSortCollection:item];

[self setToolbarItems:[NSArray arrayWithObjects:self.sortCollection, nil]];

Autolayout约束:

- (void)applyNavBarConstraints:(CGFloat)width height:(CGFloat)height
{
    if (width == 0 || height == 0) {
        return;
    }

    NSLayoutConstraint* w = [self.widthAnchor constraintEqualToConstant:width];
    NSLayoutConstraint * h = [self.heightAnchor constraintEqualToConstant:height];

    [w setActive:YES];
    [h setActive:YES];
}

堆栈跟踪:

[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. 
    (Note: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't understand, refer to the documentation for the UIView property translatesAutoresizingMaskIntoConstraints) 
(
    "<NSAutoresizingMaskLayoutConstraint:0x608000280af0 h=--& v=--& UIToolbar:0x7f85ca1327e0.width == 768   (active)>",
    "<NSLayoutConstraint:0x6000002826c0 _UIToolbarContentView:0x7f85ca1307b0.trailing == UIToolbar:0x7f85ca1327e0.trailing   (active)>",
    "<NSLayoutConstraint:0x600000282580 H:|-(0)-[_UIToolbarContentView:0x7f85ca1307b0]   (active, names: '|':UIToolbar:0x7f85ca1327e0 )>",
    "<NSLayoutConstraint:0x600000285410 H:|-(0)-[_UIButtonBarStackView:0x7f85ca135660]   (active, names: '|':_UIToolbarContentView:0x7f85ca1307b0 )>",
    "<NSLayoutConstraint:0x600000285460 _UIButtonBarStackView:0x7f85ca135660.trailing == _UIToolbarContentView:0x7f85ca1307b0.trailing   (active)>",
    "<NSLayoutConstraint:0x600000285500 UIButton:0x7f85ca131b90'Sortieren'.width == 100   (active)>",
    "<NSLayoutConstraint:0x608000280ff0 'UISV-canvas-connection' UILayoutGuide:0x6000001ba240'UIViewLayoutMarginsGuide'.leading == UIButton:0x7f85ca131b90'Sortieren'.leading   (active)>",
    "<NSLayoutConstraint:0x608000280d70 'UISV-canvas-connection' UILayoutGuide:0x6000001ba240'UIViewLayoutMarginsGuide'.trailing == UIButton:0x7f85ca131b90'Sortieren'.trailing   (active)>",
    "<NSLayoutConstraint:0x600000284f10 'UIView-leftMargin-guide-constraint' H:|-(0)-[UILayoutGuide:0x6000001ba240'UIViewLayoutMarginsGuide'](LTR)   (active, names: '|':_UIButtonBarStackView:0x7f85ca135660 )>",
    "<NSLayoutConstraint:0x600000285190 'UIView-rightMargin-guide-constraint' H:[UILayoutGuide:0x6000001ba240'UIViewLayoutMarginsGuide']-(0)-|(LTR)   (active, names: '|':_UIButtonBarStackView:0x7f85ca135660 )>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x600000285500 UIButton:0x7f85ca131b90'Sortieren'.width == 100   (active)>

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

Answer 1

从iOS11开始我也遇到过这个问题。我通过使用它自己的 XIB 创建自定义视图并在其中放置一个按钮来解决这个问题。然后您可以轻松地在 XIB 中的 InterfaceBuilder 中设置约束。然后当你真正想在 barbuttonitem 中使用它时，代码非常短：

self.customButtonView = [[[NSBundle mainBundle] loadNibNamed:NSStringFromClass([CustomButtonView class]) owner:nil options:nil] objectAtIndex:0];
[self.customButtonView.button addTarget:self action:@selector(buttonAction) forControlEvents:UIControlEventTouchUpInside];
self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:self.customButtonView];

只是不要忘记第二行，您实际上必须为按钮分配一个选择器（当然，它是自定义视图中的 IBOutlet）。