tabBar自定义

有时系统的tabBar并不能满足我们的开发需求：

这时，我们需要自定义一个tabBar。直接上代码：

 // 在tabBarController中用KVC更换掉系统tabBar
    [self setValue:[[TTTabBar alloc] init] forKeyPath:@"tabBar"];

自定义tabBar:

@interface TTTabBar()
/** 相机按钮 */
@property (nonatomic, weak) UIButton *cameraButton;
@end

@implementation XMGTabBar

- (instancetype)initWithFrame:(CGRect)frame
{
    if (self = [super initWithFrame:frame]) {// 添加相机按钮
        UIButton *cameraButton = [UIButton buttonWithType:UIButtonTypeCustom];
        [cameraButton setBackgroundImage:[UIImage imageNamed:@"camera"] forState:UIControlStateNormal];
        [cameraButton setBackgroundImage:[UIImage imageNamed:@"camera_click"] forState:UIControlStateHighlighted];
        cameraButton.size = publishButton.currentBackgroundImage.size;
        [self addSubview:cameraButton];
        self.cameraButton = cameraButton;
    }
    return self;
}

- (void)layoutSubviews
{
    [super layoutSubviews];
    self.cameraButton.center = CGPointMake(self.width * 0.5, self.height * 0.5);
    
    // 设置UITabBarButton的frame
    CGFloat buttonY = 0;
    CGFloat buttonW = self.width / 5;
    CGFloat buttonH = self.height;
    NSInteger index = 0;
    for (UIView *button in self.subviews) {
        if (![button isKindOfClass:[UIControl class]] || button == self.cameraButton) continue;
        
        // 计算按钮的x值
        CGFloat buttonX = buttonW * ((index > 1)?(index + 1):index);
        button.frame = CGRectMake(buttonX, buttonY, buttonW, buttonH);
        
        // 增加索引
        index++;
    }
}