iOS之自定义tabBar

前几天面试，被问到如果让你自定义tabbar会怎样写。所以写了的demo给大家分享一下。

• 首先需要自定义一个继承UITabBar的类去替代系统自己的UITabBar

ZYYTabBar *tabBar = [[ZYYTabBar alloc] init];
    [self setValue:tabBar forKeyPath:@"tabBar"];

• 接着就要根据自己的实际情况来自定义tabBar了，下面是我的代码：
  首先要在- (void)layoutSubviews方法中重新布局

NSInteger index = 0;
    CGFloat space = 12;
    CGFloat tabBarLabelHeight = 16;
    
    for (UIView *button in self.subviews) {
        if (![button isKindOfClass:NSClassFromString(@"UITabBarButton")]) {
            continue;
        }
        
        self.selectionIndicatorImage = [[UIImage alloc] init];
        [self bringSubviewToFront:button];
        
        UIView *tabBarImageView, *tabBarLabel, *tabBarBadgeView;
        
        for (UIView *subview in button.subviews) {
            if ([subview isKindOfClass:NSClassFromString(@"UITabBarSwappableImageView")]) {
                tabBarImageView = subview;
            } else if ([subview isKindOfClass:NSClassFromString(@"UITabBarButtonLabel")]) {
                tabBarLabel = subview;
            } else if ([subview isKindOfClass:NSClassFromString(@"_UIBadgeView")]) {
                tabBarBadgeView = subview;
            }
        }
        
        NSString *tabBarLabelText = ((UILabel *)tabBarLabel).text;
        
        CGFloat y = CGRectGetHeight(self.bounds) - (CGRectGetHeight(tabBarLabel.bounds) + CGRectGetHeight(tabBarImageView.bounds));
        NSLog(@"=======%f ======= %f", button.frame.origin.x, button.frame.size.width);
        if (y < 0) {
            if (!tabBarLabelText.length) {
                space -= tabBarLabelHeight;
            } else {
                space = 12;
            }
            button.frame = CGRectMake(button.frame.origin.x, y - space, button.frame.size.width, button.frame.size.height - y + space);
        } else {
            space = MIN(space, y);
        }
        
        index++;
    }

然后，发现超出tabBar的部分不响应点击事件，因为我们需要实现- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event方法

if (!self.clipsToBounds && !self.hidden && self.alpha > 0) {
        UIView *result = [super hitTest:point withEvent:event];
        if (result) {
            return result;
        } else {
            for (UIView *subView in self.subviews.reverseObjectEnumerator) {
                CGPoint subPoint = [subView convertPoint:point fromView:self];
                if (CGRectContainsPoint(subView.bounds, subPoint)) {
                    result = subView;
                    return result;
                }
            }
        }
    }
    return nil;

• 最后，大功告成。实现的效果如图：

附上我的demo地址：DefineTabbar_KVC