Increasing a thumbs "click area" in UISlider
ios, iphone, uislider
Solution
You have to override `thumbRectForBounds:trackRect:value:` in a custom subclass (instead of calling the method yourself like you do in your code, which does nothing except returning a value that you don't even bother to retrieve).
`thumbRectForBounds:trackRect:value:` is not a method to set the tumb rect, but to get it. The slider will internally call this `thumbRectForBounds:trackRect:value:` method to know where to draw the thumb image, so you need to override it — as explained in the documentation — to return the `CGRect` you want (so that it will be 35x35px as you wish).
Problem
I am creating a custom UISlider and wonder, how do you increase a thumb image's "click area" ? The code below works great, except the thumb's "click area" remains unchanged. If I am not wrong, I believe the standard thumb area is 19 px ? Lets say I would like to increase it to 35px with the following code below, what steps do I need to take? Keep in mind I am not an expert within this area at all. EDIT The code below is corrected and ready for copy pasta! Hope it helps you! main.h ``` #import "MyUISlider.h" @interface main : MLUIViewController <UITableViewDelegate, UITableViewDataSource, UISearchBarDelegate, UIActionSheetDelegate, UIAlertViewDelegate, MFMailComposeViewControllerDelegate, UIGestureRecognizerDelegate, MLSearchTaskDelegate, MLDeactivateDelegate, MLReceiptDelegate> { .......... } - (void)create_Custom_UISlider; ``` main.m ``` - (void)viewDidLoad { [self create_Custom_UISlider]; [self.view addSubview: customSlider]; } - (void)create_Custom_UISlider { CGRect frame = CGRectMake(20.0, 320.0, 280, 0.0); customSlider = [[MyUISlider alloc] initWithFrame:frame]; [customSlider addTarget:self action:@selector(sliderAction:) forControlEvents:UIControlEventValueChanged]; // in case the parent view draws with a custom color or gradient, use a transparent color customSlider.backgroundColor = [UIColor clearColor]; UIImage *stetchLeftTrack = [[UIImage imageNamed:@"blue_slider08.png"] stretchableImageWithLeftCapWidth: 10.0 topCapHeight:0.0]; UIImage *stetchRightTrack = [[UIImage imageNamed:@"blue_slider08.png"] stretchableImageWithLeftCapWidth: 260.0 topCapHeight:0.0]; [customSlider setThumbImage: [UIImage imageNamed:@"slider_button00"] forState:UIControlStateNormal]; [customSlider setMinimumTrackImage:stetchLeftTrack forState:UIControlStateNormal]; [customSlider setMaximumTrackImage:stetchRightTrack forState:UIControlStateNormal]; customSlider.minimumValue = 0.0; customSlider.maximumValue = 1.0; customSlider.continuous = NO; customSlider.value = 0.00; } -(void) sliderAction: (UISlider *) sender{ if(sender.value !=1.0){ [sender setValue: 0.00 animated: YES]; } else{ [sender setValue 0.00 animated: YES]; // add some code here depending on what you want to do! } } ``` EDIT (trying to subclass with the code below) MyUISlider.h ``` #import <UIKit/UIKit.h> @interface MyUISlider : UISlider { } @end ``` MyUISlider.m ``` #import "MyUISlider.h" @implementation MyUISlider - (CGRect)thumbRectForBounds:(CGRect)bounds trackRect:(CGRect)rect value:(float)value { return CGRectInset ([super thumbRectForBounds:bounds trackRect:rect value:value], 10 , 10); } @end ```