iOS11 UIBarButtonItem:leftBarButtonItem/rightBarButtonItem文字长度太长解决方案

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查看nav 的导航的层级关系

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leftBarButtonItem/rightBarButtonItem位置位于<_UIButtonBarStackView: 0x7fad96c09cf0; frame = (16 0; 351 44); layer = <CALayer: 0x6000000344c0>>

_UIButtonBarStackView 上边

leftBarButtonItem/rightBarButtonItem在iOS11存在UIStackView上

下边稍微解释一下UIStackView这个控件

‘Stack View 核心是方便垂直或水平排布多个SubView
Stack View 会为每个SubView创建和添加Auto Layout constrains，也可以自己控制SubView的大小和位置

得出结论Stack View 和他的每一个字控件的布局关心是约束关系，而不是frame

解决方案
添加约束确定leftBarButtonItem/rightBarButtonItem button 的大小

创建的button 的代码来源于《花花》

   NSString *backStr = @"backStrbackStrbackStrbackStrbackStr";
    UIImage *barItemImg = [UIImage imageNamed:@""];
    UIButton *backButton = [UIButton buttonWithType:UIButtonTypeCustom];
    backButton.frame = CGRectMake(0, 0, 40, 40);
    [backButton setImage:barItemImg forState:UIControlStateNormal];
    if (backStr.length != 0)
    {
        NSDictionary *attribute = @{NSFontAttributeName: [UIFont systemFontOfSize:15]};
        CGSize textSize = [backStr boundingRectWithSize:CGSizeMake((375-150), 44) options:NSStringDrawingTruncatesLastVisibleLine | NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading attributes:attribute context:nil].size;
        if (textSize.width > 50)
        {
            textSize.width = 50;
        }
        backButton.titleLabel.font = [UIFont systemFontOfSize:15];
        backButton.frame = CGRectMake(0, 0, barItemImg.size.width+textSize.width+10, 40);
        [backButton setTitle:backStr forState:UIControlStateNormal];
        backButton.titleLabel.lineBreakMode =NSLineBreakByTruncatingTail;
        backButton.backgroundColor = [UIColor redColor];
        backButton.imageEdgeInsets = UIEdgeInsetsMake(10, 0, 10, textSize.width+5);
        //button标题的偏移量，这个偏移量是相对于图片的
        backButton.titleEdgeInsets = UIEdgeInsetsMake(0, 0, 0, 0);
        [backButton setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
    }else
    {
        backButton.imageEdgeInsets = UIEdgeInsetsMake(0, -10, 0, 10);
    }
    backButton.frame = CGRectMake(0, 0, 40, 40);
    [backButton addTarget:self action:@selector(popLeftItemView) forControlEvents:UIControlEventTouchUpInside];
    
    UIBarButtonItem *backItem =    [[UIBarButtonItem alloc] initWithCustomView:backButton];
    [self.navigationItem setLeftBarButtonItems:@[backItem,space]];

添加约束代码

    NSLayoutConstraint *heightConstraint = [NSLayoutConstraint constraintWithItem:self.navigationItem.leftBarButtonItem.customView attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:0.0 constant:50];
    [self.navigationItem.leftBarButtonItem.customView addConstraint:heightConstraint];
    NSLayoutConstraint *heightConstraintWidth = [NSLayoutConstraint constraintWithItem:self.navigationItem.leftBarButtonItem.customView attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:0.0 constant:50];
    [self.navigationItem.leftBarButtonItem.customView addConstraint:heightConstraint];
    [self.navigationItem.leftBarButtonItem.customView addConstraint:heightConstraintWidth];

效果图

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