Change width of a UIBarButtonItem in a UINavigatio

问题:

I am creating a UIBarButtonItem and adding it to my navigation bar like so:

(void)viewDidLoad { 

   ...

   // Add the refresh button to the navigation bar
   UIButton *refreshButton = [UIButton buttonWithType:UIButtonTypeCustom];
   [refreshButton setFrame:CGRectMake(0,0,30,30)];
   [refreshButton setImage:[UIImage imageNamed:@"G_refresh_icon.png"] forState:UIControlStateNormal];
   [refreshButton addTarget:self action:@selector(refreshData) forControlEvents:UIControlEventTouchUpInside];
   UIBarButtonItem *refreshBarButton = [[[UIBarButtonItem alloc] initWithCustomView:refreshButton] autorelease];
   self.navigationItem.leftBarButtonItem = refreshBarButton;
}

It looks correct when I run, but I can select the bar button item by tapping the navigation bar anywhere from x = 0 to roughly 100. How can I adjust the selectable area to have a width of 30 px?

回答1:

One approach you might consider is creating a UIBarButtonItem by calling initWithCustomView:. This is not ideal in that you don't get "selected" states out of the box AND you have to composite your bordered background (if want that look) with your button image, but with that you can more directly specify a frame for your toolbar item. If you're using text for your title instead of images you may still need add in a background image as a subview. Anyway, I'm having the same problem right now and this code works for me:

UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"button-image.png"]];
imageView.frame = CGRectMake(0, 0, 43, 30);

UIBarButtonItem *barButtonItem = [[UIBarButtonItem alloc] initWithCustomView:imageView];

self.navigationItem.leftBarButtonItem = barButtonItem;

Right now this is the only way I know of restricting the auto-sizing of the UIBarButtonItems added to the UINavigationController's navigationItem.

Or try Maggie's solution, which is more thorough than mine.

回答2:

Since iOS 11, just setting frame for customView and not UIBarButtonItem won't work (like suggested in accepted answer). It seems like adding Autolayout to UIBarButtonItem overrides the set frame. This post gave me the idea:

navigationItem.leftBarButtonItem?.customView = yourCustomButtonView
let desiredWidth = 35.0
let desiredHeight = 35.0

let widthConstraint = NSLayoutConstraint(item: yourCustomButtonView, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: desiredWidth)
let heightConstraint = NSLayoutConstraint(item: yourCustomButtonView, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: desiredHeight)

yourCustomButtonView.addConstraints([widthConstraint, heightConstraint])

Also note, that it is preferred that you use UIButton as your CustomView as you have to rely on it to trigger the action.

回答3:

You can do it by dropping an image to the bar button item from the interface builder and changing the width of the custom view with this code:

CGRect frame = self.navigationItem.leftBarButtonItem.customView.frame;
frame.size.width = 141;
self.navigationItem.leftBarButtonItem.customView.frame = frame;

回答4:

The key thing with this is to realise that you are changing the custom view's width, rather than the UIBarButton itself.

The code is therefore:

CGRect resizedFrame = myBarButtonItem.customView.frame;
resizedFrame.size.width = myNewWidth;
myBarButtonItem.customView.frame = resizedFrame;

You will also need to trigger the layout change:

[myNavigationBar setNeedsLayout];

All this goes without saying that the layout is being done with Auto Sizing and frames. Incursions into navigation bars with Auto Layout yielded no success. See my question Auto Layout with UINavigationBar and UIBarButtonItem.

Sorry just realised that my code is almost identical to @oscartzombie. Not intentional! I'll leave this answer as I think it's worth adding the layout and other points, in addition to explaining without reference to Interface Bulder or images specifically.

回答5:

The following approach worked, see code to change width and height of the button and to add action item as well.

UIButton *imageButton = [[UIButton alloc]initWithFrame:CGRectMake(0, 0, 22, 22)];
[imageButton setBackgroundImage:[UIImage imageNamed:@"message_button"] forState:UIControlStateNormal];
[imageButton addTarget:self action:@selector(messageButtonTapped) forControlEvents:UIControlEventAllEvents];
UIBarButtonItem *leftBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:imageButton];
self.navigationItem.leftBarButtonItem = leftBarButtonItem;

Note: The target and action of the UIBarButtonItem does not apply to image view

回答6:

None of those solutions worked for me and I figure out auto-resizing thing overrides dimensions that you wrote in code.

after creating button by UIButton way, write following code block:

[self.navigationItem.rightBarButtonItem.customView.widthAnchor constraintEqualToConstant:mWidth].active = YES;
[self.navigationItem.rightBarButtonItem.customView.heightAnchor constraintEqualToConstant:mHeight].active = YES;