How can I replace the text in a round rect button with a spinner? - objective-c

Question

I have a view with a generic rounded rect button that segues to another view. When users press the rounded rect it starts a fetch. I would like to have a spinning wheel replace the text ("Next") inside the rounded rect button while the fetch is processed.
I created the spinner:
UIActivityIndicatorView *spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
[spinner startAnimating];
But I don't know how to make it replace the text in the rounded rect button.
Any suggestion? Thank you.

Answer 1

Create (or get a reference to) the button as usual, then, while handling the button click, create your spinner and set it as a subview of the button. It's probably also worth disabling the button to stop multiple clicks.
Something along the following lines should do the trick:
...
UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
button.frame = CGRectMake(10, 10, 70, 40);
[button setTitle:#"Next" forState:UIControlStateNormal];
[button addTarget:self action:#selector(click:) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:button];
...
- (void)click:(UIButton *)button {
[button setTitle:#"" forState:UIControlStateNormal];
UIActivityIndicatorView *spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
[spinner startAnimating];
spinner.frame = button.bounds;
[button addSubview:spinner];
button.enabled = NO;
// do your actual work...
}

Answer 2

I wrote a category that utilizes associated objects
UIButton+ActivityIndicator.h
// Created by reynaldo on 1/16/14.
#import <Foundation/Foundation.h>
#interface UIButton (ActivityIndicator)
- (void)startActivityIndicator;
- (void)stopActivityIndicator;
#end
UIButton+ActivityIndicator.m
// Created by reynaldo on 1/16/14.
#import <objc/runtime.h>
#import "UIButton+ActivityIndicator.h"
static char TITLE_KEY;
static char ACTIVITY_INDICATOR_KEY;
#implementation UIButton (ActivityIndicator)
- (void)startActivityIndicator {
objc_setAssociatedObject(self, &TITLE_KEY, self.currentTitle, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
[self setTitle:#"" forState:UIControlStateNormal];
UIActivityIndicatorView *activityIndicatorView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];
[self addSubview:activityIndicatorView];
activityIndicatorView.frame = CGRectMake(self.frame.size.width / 2, self.frame.size.height / 2. - 2, 7, 7);
[activityIndicatorView startAnimating];
objc_setAssociatedObject(self, &ACTIVITY_INDICATOR_KEY, activityIndicatorView, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
- (void)stopActivityIndicator {
NSString *title = objc_getAssociatedObject(self, &TITLE_KEY);
UIActivityIndicatorView *activityIndicatorView = objc_getAssociatedObject(self, &ACTIVITY_INDICATOR_KEY);
if(activityIndicatorView) {
[activityIndicatorView removeFromSuperview];
}
if(title.length) {
[self setTitle:title forState:UIControlStateNormal];
}
}
#end