iOS中的常用方法（持续更新）

1、JSON解析

- (NSDictionary *)serializedData:(NSData *)data {
    NSError *JSONSerializationError;
    NSDictionary *JSON = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:&JSONSerializationError];
    if(JSONSerializationError) {
        [NSException raise:@"JSON Serialization Error" format:@"Failed to parse weather data"];
    }
    
    return JSON;
}

 

2、背景模糊，需要UIImage+ImageEffects

 - (void)setBlurredOverlayImage {
     dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^ {       
         // Take a screen shot of this controller's view
         UIGraphicsBeginImageContextWithOptions(self.view.bounds.size, NO, 0.0);
         CGContextRef context = UIGraphicsGetCurrentContext();
        
         [self.view.layer renderInContext:context];
         UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
        
         UIGraphicsEndImageContext();
        
         // Blur the screen shot
         UIImage *blurred = [image applyBlurWithRadius:20
                                             tintColor:[UIColor colorWithWhite:0.15 alpha:0.5]
                                 saturationDeltaFactor:1.5
                                             maskImage:nil];
        
         dispatch_async(dispatch_get_main_queue(), ^ {
             // Set the blurred overlay view's image with the blurred screenshot
             self.blurredOverlayView.image = blurred;
         });
     });
 }

 

3、计算pageControl的页码

 - (void)scrollViewDidScroll:(UIScrollView *)scrollView {
     // Update the current page for the page control
     float fractionalPage = self.pagingScrollView.contentOffset.x / self.pagingScrollView.frame.size.width;
     self.pageControl.currentPage = lround(fractionalPage);
 }

 

4、图像缩放

 + (UIImage *)scale:(UIImage *)sourceImg toSize:(CGSize)size {
     UIGraphicsBeginImageContext(size);
     [sourceImg drawInRect:CGRectMake(0, 0, size.width, size.height)];
     UIImage *scaledImage = UIGraphicsGetImageFromCurrentImageContext();
     UIGraphicsEndImageContext();
     return scaledImage;
 }
 
 + (CGSize)scaleSize:(CGSize)sourceSize {
     float width = sourceSize.width;
     float height = sourceSize.height;
     if (width >= height) 
         return CGSizeMake(800, 800 * height / width);
     else
         return CGSizeMake(800 * width / height, 800);
 }

 

5、ASIHTTPRequest取消请求

 + (void)CancelRequest:(ASIHTTPRequest *)request {
     if (request != nil) {
         [request cancel];
         [request clearDelegatesAndCancel];
     }
 }

 

6、debug log switch

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 #ifdef DEBUG
 #    define NSLog(...) NSLog(__VA_ARGS__)
 #else
 #    define NSLog(...) {}
 #endif

 

7、Disk cache

NSURLCache *URLCache = [[NSURLCache alloc] initWithMemoryCapacity:4 * 1024 * 1024
                                                     diskCapacity:20 * 1024 * 1024
                                                         diskPath:nil];
[NSURLCache setSharedURLCache:URLCache];

8、AFNetworking

[[AFNetworkActivityIndicatorManager sharedManager] setEnabled:YES];
[[AFNetworkReachabilityManager sharedManager] startMonitoring];
[[AFNetworkReachabilityManager sharedManager] setReachabilityStatusChangeBlock:^(AFNetworkReachabilityStatus status) {
    NSString* title = @"网络未连接";
    switch (status) {
        case AFNetworkReachabilityStatusNotReachable:
            title = @"网络未连接";
            break;
        case AFNetworkReachabilityStatusReachableViaWiFi:
            title = @"当前wifi已连接";
            break;
        case AFNetworkReachabilityStatusReachableViaWWAN:
            title = @"当前2g/3g已连接";
            break;
        default:
            break;
    }
    [RCGlobalConfig HUDShowMessage:title addedToView:[UIApplication sharedApplication].keyWindow];
}];

9、MBProgressHUD

+ (MBProgressHUD *)HUDShowMessage:(NSString *)msg addedToView:(UIView *)view {
    static MBProgressHUD *hud = nil;
    if (!hud)
        hud = [MBProgressHUD showHUDAddedTo:view animated:YES];
        
        hud.mode = MBProgressHUDModeText;
        hud.labelText = msg;
        hud.hidden = NO;
        hud.alpha = 1.0f;
        [hud hide:YES afterDelay:1.0f];
    
    return hud;
}

10、UIBarButtonItem

+ (UIBarButtonItem *)createBarButtonItemWithTitle:(NSString *)buttonTitle Target:(id)target action:(SEL)action {
    UIBarButtonItem *item = nil;
    item = [[UIBarButtonItem alloc] initWithTitle:buttonTitle
                                            style:UIBarButtonItemStylePlain
                                           target:target
                                           action:action];
    return item;
}

+ (UIBarButtonItem *)createMenuBarButtonItemWithTarget:(id)target action:(SEL)action {
    return [[UIBarButtonItem alloc] initWithImage:[UIImage nimbusImageNamed:@"icon_menu.png"]
                                            style:UIBarButtonItemStylePlain
                                           target:target action:action];
}

+ (UIBarButtonItem *)createRefreshBarButtonItemWithTarget:(id)target action:(SEL)action {
    UIBarButtonItem *item = nil;
    item = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemRefresh
                                                         target:target action:action];
    return item;
}

11、获取UIView对应的UIViewController

#import <UIKit/UIKit.h>

@interface UIView (findViewController)

- (UIViewController *)viewController;

@end

#import "UIView+findViewController.h"

@implementation UIView (findViewController)
- (UIViewController *)viewController {
    // Traverse responder chain. Return first found view controller, which will be the view's view controller.
    UIResponder *responder = self;
    while ((responder = [responder nextResponder]))
        if ([responder isKindOfClass:[UIViewController class]])
            return (UIViewController *)responder;
    
    // If the view controller isn't found, return nil.
    return nil;
}
@end

12、获取图片，需要nimbus

#import <UIKit/UIKit.h>

@interface UIImage (nimbusImageNamed)

+ (UIImage *)nimbusImageNamed:(NSString *)imageName;

@end

#import "UIImage+nimbusImageNamed.h"

@implementation UIImage (nimbusImageNamed)

+ (UIImage *)nimbusImageNamed:(NSString *)imageName {
    NSString *imagePath = NIPathForBundleResource(nil, imageName);
    UIImage *image = [[Nimbus imageMemoryCache] objectWithName:imagePath];
    if (nil == image) {
        image = [UIImage imageWithContentsOfFile:imagePath];
        // store it in memory
        [[Nimbus imageMemoryCache] storeObject:image withName:imagePath];
    }
    
    return image;
}

@end

13、保存图片

if(photoView.image)
   UIImageWriteToSavedPhotosAlbum(photoView.image, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);

14、获取文件内容

+ (NSString *)contentForFile:(NSString *)file ofType:(NSString *)type {
    NSString *filePath=[[NSBundle mainBundle] pathForResource:file ofType:type];
    NSString *content = [NSString stringWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:nil];
    
    return content;
}

15、获取AppDelegate

+ (SFAppDelegate *)applicationDelegate {
    return (SFAppDelegate *)[[UIApplication sharedApplication] delegate];
}

16、计算字符高度

+ (float)heightOfString:(NSString *)string withWidth:(float)width font:(UIFont *)font {
    if ([NSNull null] == (id)string)
        string = @"暂时没有数据";
    
    CGSize constraintSize = CGSizeMake(width, MAXFLOAT);
    CGSize labelSize = [string sizeWithFont:font constrainedToSize:constraintSize lineBreakMode:UILineBreakModeWordWrap];
    
    return labelSize.height;
}

17、设置cookie

NSHTTPCookie *uidCookie = [NSHTTPCookie cookieWithProperties:
                           [NSDictionary dictionaryWithObjectsAndKeys:
                            @"sfuid", NSHTTPCookieName,
                            @"", NSHTTPCookieValue,
                            @".segmentfault.com", NSHTTPCookieDomain,
                            @"segmentfault.com", NSHTTPCookieOriginURL,
                            @"/", NSHTTPCookiePath,
                            @"0", NSHTTPCookieVersion,
                            nil]];

[[NSHTTPCookieStorage sharedHTTPCookieStorage] setCookie:uidCookie];

18、定义枚举

typedef NS_OPTIONS(NSUInteger, MLDays) {
    ML_DAYS_ONCE = 0,
    ML_DAYS_MON = 1,
    ML_DAYS_TUE = 1 << 1,
    ML_DAYS_WED = 1 << 2,
    ML_DAYS_THU = 1 << 3,
    ML_DAYS_FRI = 1 << 4,
    ML_DAYS_SAT = 1 << 5,
    ML_DAYS_SUN = 1 << 6,
    ML_DAYS_ALL = 0x1111111
};

19、判断是否为空

static inline BOOL isEmpty(id thing) {
    return thing == nil ||
        thing == [NSNull null] ||
        ([thing respondsToSelector:@selector(length)] && [(NSData *)thing length] == 0) ||
        ([thing respondsToSelector:@selector(count)]  && [(NSArray *)thing count] == 0);
}