How to adjust UIToolBar left and right padding

Question

I create one UIToolbar with code and another with interface builder. But, found out the two toolbar having different left and right padding which shown below:

From I

Answer 1

Before iOS 11

You had three possible solutions:

• The first was using fixed a space item UIBarButtonItem(barButtonSystemItem: .fixedSpace …) with a negative width
• The other was to override alignmentRectInsets on the custom view
• The last one, if you use UIButton as your item's custom view, you can override contentEdgeInsets and hitTest(_:with:)

Absolutely, the first solution seems better than other

UIBarButtonItem *negativeSeparator = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace target:nil action:nil];
negativeSeparator.width = -12;

if you use swift, code will be look like this

var negativeSeparator = UIBarButtonItem(barButtonSystemItem: .fixedSpace, target: nil, action: nil)
negativeSeparator.width = -12

After iOS 11(contain iOS 11)

unfortunately, all the solution can't be use in iOS 11

• first solution: setting a negative width no longer works
• second solution: override alignmentRectInsets will cause part of item no longer receives touches
• the last solution: i think override hitTest(_:with:) is not a good idea, don't do this please!

You can also see some suggestion on the Developer Forums, but after you look all the comment, you will find suggestion on this topic is to create a custom UINavigationBar subclass and do something complexity.

Oh my god, All i want to do is to change the padding, not the navigation bar!

Fortunately, we can do this with a trick in iOS 11!

Here We Go:

1. create a custom button

• set translatesAutoresizingMaskIntoConstraints as false
• override alignmentRectInsets
  • item in right side use UIEdgeInsets(top: 0, left: -8, bottom: 0, right: 8)
  • item in left side use UIEdgeInsets(top: 0, left: 8, bottom: 0, right: -8)

    if you don't know alignmentRectInsets, you can read this blog first

swift version

var customButton = UIButton(type: .custom)
customButton.overrideAlignmentRectInsets = UIEdgeInsets(top: 0, left: x, bottom: 0, right: -x) // you should do this in your own custom class
customButton.translatesAutoresizingMaskIntoConstraints = false;

objective-c version

UIButton *customButton = [UIButton buttonWithType:UIButtonTypeCustom];
customButton.overrideAlignmentRectInsets = UIEdgeInsetsMake(0, x, 0, -x); // you should do this in your own custom class
customButton.translatesAutoresizingMaskIntoConstraints = NO;

2. create an item with your custom button

swift version

var item = UIBarButtonItem(customView: customButton)

objective-c version

UIBarButtonItem *item = [[UIBarButtonItem alloc] initWithCustomView:customButton]

3. create a fixedSpace type UIBarButtonItem with positive width

set a positive value, not a negative value

swift version

var positiveSeparator = UIBarButtonItem(barButtonSystemItem:.fixedSpace, target: nil, action: nil)
positiveSeparator.width = 8

objective-c version

UIBarButtonItem *positiveSeparator = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace target:nil action:nil];
positiveSeparator.width = 8;

4. set an array to leftitems or rightitems

fixedSpace type UIBarButton item must be the first element in array.

swift version

self.navigationItem.leftBarButtonItems = [positiveSeparator, item, ...]

objective-c version

self.navigationItem.leftBarButtonItems = @{positiveSeparator, item, ...}

Well Done

after you doing all of the steps, you will see your padding become smaller and type area seems correct!

If you find something wrong, please let me know! I will try my best to answer your question!

Note

Before iOS 11, you should care about the device's screen width; if the screen is 5.5 inch, the negative is -12 pt, on other screens is -8pt.

If you use my solution on iOS 11, you don't need to care about the device screen, just set 8pt, You should care about item's position in navigation bar, left side or right side, this will affect your custom view's alignmentRectInsets

Want more tap area

If you want to promise your tap area is larger than 44 * 44 , you can override method below

- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event{
    CGSize acturalSize = self.frame.size;
    CGSize minimumSize = kBarButtonMinimumTapAreaSize;
    CGFloat verticalMargin = acturalSize.height - minimumSize.height >= 0 ? 0 : ((minimumSize.height - acturalSize.height ) / 2);
    CGFloat horizontalMargin = acturalSize.width - minimumSize.width >= 0 ? 0 : ((minimumSize.width - acturalSize.width ) / 2);
    CGRect newArea = CGRectMake(self.bounds.origin.x - horizontalMargin, self.bounds.origin.y - verticalMargin, self.bounds.size.width + 2 * horizontalMargin, self.bounds.size.height + 2 * verticalMargin);
    return CGRectContainsPoint(newArea, point);
}