A subclass of UIView that allows a developer to draw in a view without having to subclass UIView

ZDrawView

typedef void (^DrawBlock)(CGContextRef currentContext, CGRect drawRect, UIView *selfView);


@interface ZDrawView : UIView

@property (nonatomic, copy) DrawBlock drawBlock;

- (instancetype)initWithBlock:(DrawBlock)block;
+ (instancetype)viewWithBlock:(DrawBlock)block;

+ (instancetype)horizontalLine;
+ (instancetype)horizontalLineWithColor:(UIColor *)lineColor;

+ (instancetype)verticalLine;
+ (instancetype)verticalLineWithColor:(UIColor *)lineColor;

- (void)drawRect:(CGRect)drawRect;

@end

@implementation ZDrawView

#pragma mark - Init methods

- (instancetype)initWithBlock:(DrawBlock)block{
    self = [super init];
    if (self){
        self.drawBlock = block;
    }
    
    return self;
}

+ (instancetype)viewWithBlock:(DrawBlock)block{
    return [[[self class]alloc]initWithBlock:block];
}


#pragma mark - Horizontal line methods

+ (instancetype)horizontalLine{
    return [[self class]horizontalLineWithColor:[UIColor darkGrayColor]];
}

+ (instancetype)horizontalLineWithColor:(UIColor *)lineColor{
    return [[[self class]alloc]initWithBlock:^(CGContextRef currentContext, CGRect drawRect, UIView *selfView) {
        [lineColor setStroke];
        CGContextMoveToPoint(currentContext, drawRect.origin.x, drawRect.origin.y);
        CGContextAddLineToPoint(currentContext, drawRect.origin.x + drawRect.size.width, drawRect.origin.y);
        CGContextStrokePath(currentContext);
    }];
}

#pragma mark - Vertical line

+ (instancetype)verticalLine{
    return [[self class]verticalLineWithColor:[UIColor darkGrayColor]];
}

+ (instancetype)verticalLineWithColor:(UIColor *)lineColor{
    return [[[self class]alloc]initWithBlock:^(CGContextRef currentContext, CGRect drawRect, UIView *selfView) {
        [lineColor setStroke];
        CGContextMoveToPoint(currentContext, drawRect.origin.x, drawRect.origin.y);
        CGContextAddLineToPoint(currentContext, drawRect.origin.x, drawRect.origin.y + drawRect.size.height);
        CGContextStrokePath(currentContext);
    }];
}

#pragma mark - drawRect method

- (void)drawRect:(CGRect)drawRect{
    [super drawRect:drawRect];
    
    if (self.drawBlock != nil){
        self.drawBlock(UIGraphicsGetCurrentContext(), drawRect, self);
    }
}

@end