How to line break long large title in iOS 11?

问题

I am trying to use the new large title system in iOS 11 using Swift. When the title gets too long (see image example), it adds ... instead of line breaking or shrinking the text size. How can I add a line break?

Here is some of the code I'm using to set up the title:

self.navigationController?.navigationBar.prefersLargeTitles = true
self.navigationController?.navigationBar.largeTitleTextAttributes = [NSForegroundColorAttributeName: MyGlobalVariable.themeMainColor]
self.navigationController?.navigationBar.largeTitleTextAttributes = [NSFontAttributeName: UIFont.systemFont(ofSize: 22)]
navigationItem.title = "Search by Name"

回答1:

Try this:

for navItem in (self.navigationController?.navigationBar.subviews)! {
    for itemSubView in navItem.subviews {
        if let largeLabel = itemSubView as? UILabel {
            largeLabel.text = self.title
            largeLabel.numberOfLines = 0
            largeLabel.lineBreakMode = .byWordWrapping
        }
    }
}

It worked for me.

回答2:

This is Objective-C but what I did worked with backButton. I override the setTitle method of UIViewController like this :

-(void)setTitle:(NSString *)title{

    [super setTitle:title];

    for(id item in self.navigationController.navigationBar.subviews){

        if([item isKindOfClass:[UIView class]]){

            UIView *lc_view = (UIView *)item;

            for(id subItem in lc_view.subviews){

                if([subItem isKindOfClass:[UILabel class]]){

                    UILabel *lc_label = (UILabel *)subItem;

                    lc_label.text = self.title;
                    lc_label.numberOfLines=0;
                    lc_label.lineBreakMode = NSLineBreakByWordWrapping;
                }
            }
        }
    }

    [self.navigationController.navigationBar layoutSubviews];
    [self.navigationController.navigationBar layoutIfNeeded];
}

Then where I want to set the title I simply did :

dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.02 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

    self.title=@"Lorem ipsum dolor sit amet, consectetuer adipiscing elit.";

});

In my case (changing title in UIPageViewController didFinishAnimating method) it seems that a delay < 0.02 didn't work.

来源：https://stackoverflow.com/questions/46438881/how-to-line-break-long-large-title-in-ios-11

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