Why page Push animation Tabbar moving up in the iPhone X

Question

I build a app Demo, use hidesBottomBarWhenPushed hide Tabbar in Push Animation.

But, When I click Jump Button Tabbar move up!? like this:

Answer 1

Answer provided by VoidLess fixes TabBar problems only partially. It fixes layout problems within tabbar, but if you use viewcontroller that hides tabbar, the tabbar is rendered incorrectly during animations (to reproduce it is best 2 have 2 segues - one modal and one push. If you alternate the segues, you can see tabbar being rendered out of place). See the code bellow that fixes both of the problems. Good job apple.

class SafeAreaFixTabBar: UITabBar {

var oldSafeAreaInsets = UIEdgeInsets.zero

@available(iOS 11.0, *)
override func safeAreaInsetsDidChange() {
    super.safeAreaInsetsDidChange()

    if oldSafeAreaInsets != safeAreaInsets {
        oldSafeAreaInsets = safeAreaInsets

        invalidateIntrinsicContentSize()
        superview?.setNeedsLayout()
        superview?.layoutSubviews()
    }
}

override func sizeThatFits(_ size: CGSize) -> CGSize {
    var size = super.sizeThatFits(size)
    if #available(iOS 11.0, *) {
        let bottomInset = safeAreaInsets.bottom
        if bottomInset > 0 && size.height < 50 && (size.height + bottomInset < 90) {
            size.height += bottomInset
        }
    }
    return size
}

override var frame: CGRect {
    get {
        return super.frame
    }
    set {
        var tmp = newValue
        if let superview = superview, tmp.maxY != 
        superview.frame.height {
            tmp.origin.y = superview.frame.height - tmp.height
        }

        super.frame = tmp
        }
    }
}
}

Objective-C code:

@implementation VSTabBarFix {
    UIEdgeInsets oldSafeAreaInsets;
}


- (void)awakeFromNib {
    [super awakeFromNib];

    oldSafeAreaInsets = UIEdgeInsetsZero;
}


- (void)safeAreaInsetsDidChange {
    [super safeAreaInsetsDidChange];

    if (!UIEdgeInsetsEqualToEdgeInsets(oldSafeAreaInsets, self.safeAreaInsets)) {
        [self invalidateIntrinsicContentSize];

        if (self.superview) {
            [self.superview setNeedsLayout];
            [self.superview layoutSubviews];
        }
    }
}

- (CGSize)sizeThatFits:(CGSize)size {
    size = [super sizeThatFits:size];

    if (@available(iOS 11.0, *)) {
        float bottomInset = self.safeAreaInsets.bottom;
        if (bottomInset > 0 && size.height < 50 && (size.height + bottomInset < 90)) {
            size.height += bottomInset;
        }
    }

    return size;
}


- (void)setFrame:(CGRect)frame {
    if (self.superview) {
        if (frame.origin.y + frame.size.height != self.superview.frame.size.height) {
            frame.origin.y = self.superview.frame.size.height - frame.size.height;
        }
    }
    [super setFrame:frame];
}


@end

Answer 2

This is my way。 Declare a subclass of UITabBar, such as ActionTabBar

swift 3,4

class ActionTabBar: UITabBar {

    override var frame: CGRect {
        get {
            return super.frame
        }
        set {
            var tmp = newValue
            if let superview = self.superview, tmp.maxY != superview.frame.height {
                tmp.origin.y = superview.frame.height - tmp.height
            }
            super.frame = tmp
        }
    }
}

Objective-C

@implementation ActionTabbar

- (void)setFrame:(CGRect)frame
{
    if (self.superview && CGRectGetMaxY(self.superview.bounds) != CGRectGetMaxY(frame)) {
        frame.origin.y = CGRectGetHeight(self.superview.bounds) - CGRectGetHeight(frame);
    }
    [super setFrame:frame];
}

@end