Showing UIActivityIndicatorView on UISearchBar, depending on state of a request operation or session task

UISearchBar+AFNetworking.h

//
//  UISearchBar+AFNetworking.h
//
//  Created by Huy Nguyen on 7/15/14.
//  Copyright (c) 2014 Huy Nguyen. All rights reserved.
//

#import <Foundation/Foundation.h>

#import <Availability.h>

#if defined(__IPHONE_OS_VERSION_MIN_REQUIRED)

#import <UIKit/UIKit.h>

@class AFURLConnectionOperation;

/**
 This category adds methods to the UIKit framework's `UISearchBar` class. The methods in this category provide support for automatically adding an UIActivityIndicatorView, starting and stopping its animation depending on the loading state of a request operation or session task.
 The implementation of this category is greatly inspired by UIActivityIndicatorView+AFNetworking.
 */
@interface UISearchBar (AFNetworking)

///----------------------------------
/// @name Animating for Session Tasks
///----------------------------------

/**
 Binds the animating state to the state of the specified task.
 
 @param task The task. If `nil`, automatic updating from any previously specified operation will be disabled.
 */
#if __IPHONE_OS_VERSION_MIN_REQUIRED >= 70000
- (void)setAnimatingWithStateOfTask:(NSURLSessionTask *)task activityIndicatorStyle:(UIActivityIndicatorViewStyle)style;
#endif

///---------------------------------------
/// @name Animating for Request Operations
///---------------------------------------

/**
 Binds the animating state to the execution state of the specified operation.
 
 @param operation The operation. If `nil`, automatic updating from any previously specified operation will be disabled.
 */
- (void)setAnimatingWithStateOfOperation:(AFURLConnectionOperation *)operation activityIndicatorStyle:(UIActivityIndicatorViewStyle)style;

@end

#endif

UISearchBar+AFNetworking.m

//
//  UISearchBar+AFNetworking.m
//
//  Created by Huy Nguyen on 7/15/14.
//  Copyright (c) 2014 Huy Nguyen. All rights reserved.
//

#import "UISearchBar+AFNetworking.h"

#if defined(__IPHONE_OS_VERSION_MIN_REQUIRED)

#import "AFHTTPRequestOperation.h"

#if __IPHONE_OS_VERSION_MIN_REQUIRED >= 70000
#import "AFURLSessionManager.h"
#endif

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

@interface UISearchBar ()

@property(nonatomic, strong) UITextField *textField;
@property(nonatomic, strong) UIActivityIndicatorView *activityIndicatorView;
@property(nonatomic, strong) UIView *searchIconView;

@end

@implementation UISearchBar (AFNetworking)

#if __IPHONE_OS_VERSION_MIN_REQUIRED >= 70000
- (void)setAnimatingWithStateOfTask:(NSURLSessionTask *)task activityIndicatorStyle:(UIActivityIndicatorViewStyle)style {
    NSNotificationCenter *notificationCenter = [NSNotificationCenter defaultCenter];
    
    [notificationCenter removeObserver:self name:AFNetworkingTaskDidResumeNotification object:nil];
    [notificationCenter removeObserver:self name:AFNetworkingTaskDidSuspendNotification object:nil];
    [notificationCenter removeObserver:self name:AFNetworkingTaskDidCompleteNotification object:nil];
    
    if (task) {
        if (task.state != NSURLSessionTaskStateCompleted) {
            if (task.state == NSURLSessionTaskStateRunning) {
                [self startAnimating];
            } else {
                [self stopAnimating];
            }
            
            [notificationCenter addObserver:self selector:@selector(startAnimatingSafely) name:AFNetworkingTaskDidResumeNotification object:task];
            [notificationCenter addObserver:self selector:@selector(stopAnimatingSafely) name:AFNetworkingTaskDidCompleteNotification object:task];
            [notificationCenter addObserver:self selector:@selector(stopAnimatingSafely) name:AFNetworkingTaskDidSuspendNotification object:task];
        }
    }

    self.activityIndicatorView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:style];
}
#endif

#pragma mark -

- (void)setAnimatingWithStateOfOperation:(AFURLConnectionOperation *)operation activityIndicatorStyle:(UIActivityIndicatorViewStyle)style {
    NSNotificationCenter *notificationCenter = [NSNotificationCenter defaultCenter];
    
    [notificationCenter removeObserver:self name:AFNetworkingOperationDidStartNotification object:nil];
    [notificationCenter removeObserver:self name:AFNetworkingOperationDidFinishNotification object:nil];
    
    if (operation) {
        if (![operation isFinished]) {
            if ([operation isExecuting]) {
                [self startAnimating];
            } else {
                [self stopAnimating];
            }
            
            [notificationCenter addObserver:self selector:@selector(startAnimatingSafely) name:AFNetworkingOperationDidStartNotification object:operation];
            [notificationCenter addObserver:self selector:@selector(stopAnimatingSafely) name:AFNetworkingOperationDidFinishNotification object:operation];
        }
    }
    
    self.activityIndicatorView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:style];
}

#pragma mark -

- (UITextField *)textField {
    return objc_getAssociatedObject(self, @selector(textField));
}

- (void)setTextField:(UITextField *)textField {
    objc_setAssociatedObject(self, @selector(textField), textField, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

- (UIActivityIndicatorView *)activityIndicatorView {
    return objc_getAssociatedObject(self, @selector(activityIndicatorView));
}

- (void)setActivityIndicatorView:(UIActivityIndicatorView *)activityIndicatorView {
    objc_setAssociatedObject(self, @selector(activityIndicatorView), activityIndicatorView, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

- (UIView *)searchIconView {
    return objc_getAssociatedObject(self, @selector(searchIconView));
}

- (void)setSearchIconView:(UIView *)searchIconView {
    objc_setAssociatedObject(self, @selector(searchIconView), searchIconView, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

- (void)startAnimatingSafely {
    dispatch_async(dispatch_get_main_queue(), ^{
        [self startAnimating];
    });
}

- (void)stopAnimatingSafely {
    dispatch_async(dispatch_get_main_queue(), ^{
        [self stopAnimating];
    });
}

- (void)startAnimating {
    [self setUpViews];
    self.textField.leftView = self.activityIndicatorView;
    [self.activityIndicatorView startAnimating];
}

- (void)stopAnimating {
    [self setUpViews];
    self.textField.leftView = self.searchIconView;
    [self.activityIndicatorView stopAnimating];
}

- (void)setUpViews {
    if (self.textField == nil) {
        self.textField = [self subviewOfClass:[UITextField class]];
        self.searchIconView = self.textField.leftView;
    }
}

@end

#endif

UIView+SearchSubview.h

//
//  UIView+SearchSubview.h
//
//  Created by Huy Nguyen on 7/15/14.
//  Copyright (c) 2014 Huy Nguyen. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface UIView (SearchSubview)

- (id)subviewOfClass:(Class)class;

@end

UIView+SearchSubview.m

//
//  UIView+SearchSubview.m
//
//  Created by Huy Nguyen on 7/15/14.
//  Copyright (c) 2014 Huy Nguyen. All rights reserved.
//

#import "UIView+SearchSubview.h"

@implementation UIView (SearchSubview)

- (id)subviewOfClass:(Class)class {
    for (UIView *subview in self.subviews) {
        if ([subview isKindOfClass:class]) {
            return subview;
        }
        UIView *secondLevelSubview = [subview subviewOfClass:class];
        if (secondLevelSubview != nil) {
            return secondLevelSubview;
        }
    }
    return nil;
}

@end