如何处理iOS 11导航BarButtonItems错误？

Question

我在iOS 11中发现了一个UINavigationBar错误。用self.navigationItem.rightBarButtonItems = @[fixSpaceItem, item]在viewDidLoad中快速设置导航项目按钮。使用手势弹出，但我并不是真的弹回，当弹回开始时，我松开手指，让视图控制器取消弹出，然后右导航按钮项目消失。左边的项目按钮也有同样的问题。要重现此错误，您必须添加类似于[[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace target:nil action:nil]的fixSpaceItem。而真实的设备而不是模拟器可以重现bug。下面是我的主要代码：

- (void)viewDidLoad {
    [super viewDidLoad];

    self.navigationController.interactivePopGestureRecognizer.enabled = YES;
    self.navigationController.interactivePopGestureRecognizer.delegate = self;

    self.navigationItem.rightBarButtonItems = @[[self negativeSpacerWithWidth:5],[self rightButton]];
    self.navigationItem.leftBarButtonItems = @[[self negativeSpacerWithWidth:5], [self leftButton]];

}

- (UIBarButtonItem *)leftButton {
    UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, 35, 35)];
    [button setImage:[UIImage imageNamed:@"icon_app_back_normal"] forState:UIControlStateNormal];
    [button addTarget:self action:@selector(back) forControlEvents:UIControlEventTouchUpInside];
    UIBarButtonItem *item = [[UIBarButtonItem alloc] initWithCustomView:button];
    return item;
}

- (UIBarButtonItem *)rightButton {
    UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, 35, 35)];
    [button setImage:[UIImage imageNamed:@"setting"] forState:UIControlStateNormal];
    UIBarButtonItem *item = [[UIBarButtonItem alloc] initWithCustomView:button];
    return item;
}

- (UIBarButtonItem *)negativeSpacerWithWidth:(CGFloat)width {
    UIBarButtonItem *spacer = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace target:nil action:nil];
    [spacer setWidth:width];
    return spacer;
}

Answer 1

当您将FixedSpace BarButtonItem添加到BarButtonItem array时，它似乎是一个错误。如果你想设置导航项目的偏移量，可能不得不使用另一种方式，例如更改按钮的imageEdgeInsets。

- (void)viewDidLoad {
    [super viewDidLoad];

    // Do not set Fixed Space type button item.
    self.navigationItem.leftBarButtonItem = [self leftButton];
    self.navigationItem.rightBarButtonItem = [self rightButton];

    // It work too
    //self.navigationItem.leftBarButtonItems = @[[self leftButton], [self leftButton]];
    //self.navigationItem.rightBarButtonItems = @[[self rightButton], [self rightButton]];


    self.navigationController.interactivePopGestureRecognizer.enabled = YES;
    self.navigationController.interactivePopGestureRecognizer.delegate = self;
}

- (UIBarButtonItem *)leftButton
{
    UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, 35, 35)];
    //...

    // to add offset you want
    button.imageEdgeInsets = UIEdgeInsetsMake(0, -15, 0, 15);

    UIBarButtonItem *item = [[UIBarButtonItem alloc] initWithCustomView:button];
    return item;
}

- (UIBarButtonItem *)rightButton
{
    UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, 35, 35)];
    //...

    // to add offset you want
    button.imageEdgeInsets = UIEdgeInsetsMake(0, 15, 0, -15);

    UIBarButtonItem *item = [[UIBarButtonItem alloc] initWithCustomView:button];
    return item;
}

Answer 2

我试着调整图像的大小，使其适合导航项目，并成功了。虽然您不需要实际调整图像的大小，但您可以使用下面提供的函数在运行时调整图像的大小。

    UIImage *imgCart = [self imageWithImage:[UIImage imageNamed:@"ic_cart"] scaledToSize:CGSizeMake(35, 35)] ;
    UIButton *btnCart = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, 30, 30)];
    [btnCart addTarget:self action:@selector(btnCartClicked:) forControlEvents:UIControlEventTouchUpInside];
    [btnCart setBackgroundImage:imgCart forState:UIControlStateNormal];
    self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:btnCart];



-(UIImage *)imageWithImage:(UIImage *)image scaledToSize:(CGSize)newSize {
    //UIGraphicsBeginImageContext(newSize);
    // In next line, pass 0.0 to use the current device's pixel scaling factor (and thus account for Retina resolution).
    // Pass 1.0 to force exact pixel size.
    UIGraphicsBeginImageContextWithOptions(newSize, NO, 0.0);
    [image drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;
}

Answer 3

let hamButtonWidthConstraint = hamButton.widthAnchor.constraint(equalToConstant: 40)

let hamButtonHeightConstraint = hamButton.heightAnchor.constraint(equalToConstant: 40)

hamButtonWidthConstraint.isActive = true

hamButtonHeightConstraint.isActive = true