WIP tooltips for Mac Catalyst

UIView+Tooltips.h

//
//  UIView+Tooltips.h
//  Crossword
//
//  Created by Steven Troughton-Smith on 13/09/2019.
//  Copyright © 2019 Steven Troughton-Smith. All rights reserved.
//

#import <UIKit/UIKit.h>

NS_ASSUME_NONNULL_BEGIN

@interface UITooltipView : UIView

@property BOOL visible;

+ (instancetype)sharedInstance;

-(void)showFromRect:(CGRect)windowRect;
-(void)hide;

@property UILabel *tooltipLabel;

/* Private */
-(void)_sizeToFit;

@end

@interface UIView (Tooltips)

@property NSString *toolTip;

/* Private */
@property BOOL _tooltipMouseOver;
@property UIHoverGestureRecognizer *_tooltipRecognizer;

@end


NS_ASSUME_NONNULL_END

UIView+Tooltips.m

//
//  UIView+Tooltips.m
//  Crossword
//
//  Created by Steven Troughton-Smith on 13/09/2019.
//  Copyright © 2019 Steven Troughton-Smith. All rights reserved.
//

#import "UIView+Tooltips.h"
#import <objc/runtime.h>

@implementation UITooltipView

+ (instancetype)sharedInstance
{
	static UITooltipView *sharedInstance = nil;
	static dispatch_once_t onceToken; // onceToken = 0
	dispatch_once(&onceToken, ^{
		sharedInstance = [[UITooltipView alloc] init];
	});
	
	return sharedInstance;
}

- (instancetype)init
{
	self = [super init];
	if (self) {
		UIBlurEffect *blurEffect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleSystemMaterial];
		UIVisualEffectView *blurView = [[UIVisualEffectView alloc] initWithEffect:blurEffect];
		
		blurView.bounds = self.bounds;
		blurView.autoresizingMask = UIViewAutoresizingFlexibleWidth|UIViewAutoresizingFlexibleHeight;
		
		[self addSubview:blurView];
		
		self.tooltipLabel = [[UILabel alloc] init];
		
		self.tooltipLabel.text = @"";
		self.tooltipLabel.font = [UIFont systemFontOfSize:14];
		self.tooltipLabel.autoresizingMask = UIViewAutoresizingFlexibleWidth|UIViewAutoresizingFlexibleHeight;
		self.tooltipLabel.lineBreakMode = NSLineBreakByClipping;
		
		[[blurView contentView] addSubview:self.tooltipLabel];
		
		self.layer.borderWidth = 1.0/[UIScreen mainScreen].scale;
		self.layer.borderColor = [UIColor secondarySystemFillColor].CGColor;
		
		self.layer.shadowColor = [UIColor blackColor].CGColor;
		self.layer.shadowRadius = 6;
		self.layer.shadowOffset = CGSizeMake(0, 0);
		self.layer.shadowOpacity = 0.3;
	}
	return self;
}

-(void)_sizeToFit
{
	[self.tooltipLabel sizeToFit];
	
	self.frame = CGRectInset(self.tooltipLabel.bounds, -5, -3);
	
	self.tooltipLabel.frame = CGRectInset(self.bounds, 5, 3);
}

-(void)showFromRect:(CGRect)convertedRect
{
	[CATransaction setDisableActions:YES];
	[self _sizeToFit];
	
	CGRect labelRect = self.bounds;
	self.alpha = 0;
	self.frame = CGRectMake(convertedRect.origin.x+convertedRect.size.width/2-labelRect.size.width/2, convertedRect.origin.y+convertedRect.size.height, self.frame.size.width, self.frame.size.height);
	[CATransaction setDisableActions:NO];
	
	self.visible = YES;
	
	[UIView animateWithDuration:0.1 animations:^{
		self.alpha = 1;
	} completion:nil];
	
}

-(void)hide
{
	[UIView animateWithDuration:0.1 animations:^{
		self.alpha = 0;
	} completion:^(BOOL finished) {
		self.visible = NO;
	}];
}

@end


@implementation UIView (Tooltips)

#pragma mark - Properties

-(void)set_tooltipMouseOver:(BOOL)tooltipMouseOver
{
	objc_setAssociatedObject(self, @selector(_tooltipMouseOver), @(tooltipMouseOver), OBJC_ASSOCIATION_ASSIGN);
}

- (BOOL)_tooltipMouseOver
{
	return [objc_getAssociatedObject(self, @selector(_tooltipMouseOver)) boolValue];
}

-(void)set_tooltipRecognizer:(UIHoverGestureRecognizer *)obj
{
	objc_setAssociatedObject(self, @selector(_tooltipRecognizer), obj, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

- (UIHoverGestureRecognizer *)_tooltipRecognizer
{
	return objc_getAssociatedObject(self, @selector(_tooltipRecognizer));
}

-(void)setToolTip:(NSString *)obj
{
	objc_setAssociatedObject(self, @selector(toolTip), obj, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
	
	if (!self._tooltipRecognizer && obj && [obj length])
		[self _installTooltipRecognizer];
}

- (NSString *)toolTip
{
	return objc_getAssociatedObject(self, @selector(toolTip));
}

#pragma mark - Recognizer

-(void)_installTooltipRecognizer
{
	self._tooltipRecognizer = [[UIHoverGestureRecognizer alloc] initWithTarget:self action:@selector(tooltipHover:)];
	[self addGestureRecognizer:self._tooltipRecognizer];
}

-(void)_beginTooltipTimer
{
	CGFloat time = 2.0;
	
	if ([UITooltipView sharedInstance].visible)
		time = 0.0;
	
	[NSTimer scheduledTimerWithTimeInterval:time repeats:NO block:^(NSTimer * _Nonnull timer) {
		if (self._tooltipMouseOver)
		{
			CGRect convertedRect = [self convertRect:self.bounds toView:self.window];
			
			[UITooltipView sharedInstance].tooltipLabel.text = self.toolTip;
			[self.window addSubview:[UITooltipView sharedInstance]];
			[[UITooltipView sharedInstance] showFromRect:convertedRect];
		}
	}];
}

-(void)tooltipHover:(UIHoverGestureRecognizer *)recognizer
{
	switch (recognizer.state)
	{
		case UIGestureRecognizerStateBegan:
		{
			self._tooltipMouseOver = YES;
			[self _beginTooltipTimer];
			
			break;
		}
		case UIGestureRecognizerStateChanged:
		{
			break;
		}
		case UIGestureRecognizerStateEnded:
		case UIGestureRecognizerStateCancelled:
		case UIGestureRecognizerStateFailed:
		{
			self._tooltipMouseOver = NO;
			[[UITooltipView sharedInstance] hide];
			
			break;
		}
		default:
			break;
	}
}

@end