Convert UIView to UIImage. Taking screenshot programatically iOS.

-(UIImage *)convertViewToImage:(UIView*)view
{
    UIGraphicsBeginImageContext(view.bounds.size);//context create a canvas to draw 
    [view drawViewHierarchyInRect: view.bounds afterScreenUpdates:YES];//draws the view hierarchy into the current context
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();//Fetches UIImage from the current context
    UIGraphicsEndImageContext();// Context ends.
 
    return image;
}

Increase button hit area by changing the Edge Inset. UIButton with UIEdgeInsetsMake.

#import <objc/runtime.h>

@implementation UIButton (Extensions)

@dynamic hitTestEdgeInsets;

static const NSString *KEY_HIT_TEST_EDGE_INSETS = @"HitTestEdgeInsets";

-(void)setHitTestEdgeInsets:(UIEdgeInsets)hitTestEdgeInsets {

    NSValue *value = [NSValue value:&hitTestEdgeInsets withObjCType:@encode(UIEdgeInsets)];

    objc_setAssociatedObject(self, &KEY_HIT_TEST_EDGE_INSETS, value, OBJC_ASSOCIATION_RETAIN_NONATOMIC);

}

-(UIEdgeInsets)hitTestEdgeInsets {

    NSValue *value = objc_getAssociatedObject(self, &KEY_HIT_TEST_EDGE_INSETS);

    if(value) {

        UIEdgeInsets edgeInsets; 
       [value getValue:&edgeInsets]; 
       return edgeInsets;

    }else {

        return UIEdgeInsetsZero;

    }

}

- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event {

    if(UIEdgeInsetsEqualToEdgeInsets(self.hitTestEdgeInsets, UIEdgeInsetsZero) ||       !self.enabled || self.hidden) {

        return [super pointInside:point withEvent:event];

    }

    

    CGRect relativeFrame = self.bounds;

    CGRect hitFrame = UIEdgeInsetsInsetRect(relativeFrame, self.hitTestEdgeInsets);

    

    return CGRectContainsPoint(hitFrame, point);

}

@end

Usage-

 _backBtn = [[UIButton alloc]initWithFrame:CGRectMake(16, 12, 28, 28)];    

    [_backBtn setBackgroundImage:[UIImage imageNamed:@"backphoto"] forState:UIControlStateNormal];

    [_backBtn addTarget:self action:@selector(backButtonClicked) forControlEvents:UIControlEventTouchUpInside];

    [_backBtn setHitTestEdgeInsets:UIEdgeInsetsMake(-15, -15, -15, -15)];//increase the hit area of button by 15 on all sides top,left,bottom,right

Pass or associate id (any object) with NSObject(UIView,UIAlertView, etc). Add string Tags to NSObject.

Create a category of NSObject Class

.h

#import <Foundation/Foundation.h>

#import <objc/runtime.h>

#pragma mark - NSObject

@interface NSObject (CCFoundation)

- (id)associativeObjectForKey: (NSString *)key;

- (void)setAssociativeObject: (id)object forKey: (NSString *)key;

@end

.m

#pragma mark - NSObject

@implementation NSObject (CCFoundation)

static char associativeObjectsKey;

- (id)associativeObjectForKey: (NSString *)key {

    NSMutableDictionary *dict = objc_getAssociatedObject(self, &associativeObjectsKey);

    return [dict objectForKey: key];

}

- (void)setAssociativeObject: (id)object forKey: (NSString *)key {

    NSMutableDictionary *dict = objc_getAssociatedObject(self, &associativeObjectsKey);

    if (!dict) {

        dict = [[NSMutableDictionary alloc] init];

        objc_setAssociatedObject(self, &associativeObjectsKey, dict, OBJC_ASSOCIATION_RETAIN);

    } [dict setObject: object objectForKey: key];

}

@end

-------------------:USAGE:-----------------

UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:@"title" message:@"alert" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:@"OK",nil];

// Associate MyObject(of type id) with a key

[alertView setAssociatedObject:MyDict forKey:@"kKeyResponse"];

alertView.tag = KTagAlert;

[alertView show];

#pragma mark- Alert View Delegate-

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex;

{

    if (alertView.tag == KTagNotificationAlert) {

// Fetch the associated object(id) currently dictionary 

   NSMutableDictionary *associatedObjectDict = [alertView associativeObjectForKey:@"kKeyResponse"];

NSLog(@"%@", associatedObjectDict);

        if (associatedObjectDict) {

            //Valid

            switch (buttonIndex) {

                case 0:{// cancel pressed

                    break;

                }

                case 1: {// ok pressed

                    break;

                }

                default:

                    break;

            }

        }

        else{

            [[[UIAlertView alloc]initWithTitle:@"Error" message:@"Please try later." delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil] show];

        }

    }

}

1. Refer Link
2. Refer Link 

Replace Null, , (null) , nil , NSNull, Values from NSString with empty string @""

+(NSString*)replaceNullValuesWithEmptyString:(id)tempObj

{

    if (([tempObj isKindOfClass:[NSNull class]])||

        (tempObj == nil) ||

        (tempObj == (id)[NSNull null])||

        [tempObj isEqual:[NSNull null]] ||

        [tempObj isEqual:nil]) {

    }

    else {

        if([tempObj respondsToSelector:@selector(isEqualToString:)]) {

            if ([tempObj isEqualToString:@"<null>"] ||

                [tempObj isEqualToString:@"(null)"]) {

            }

            else {

                if ([tempObj respondsToSelector:@selector(length)]) {

                    if ([tempObj length]>0) {

                         NSLog(@"Check Passed.");

                        return tempObj;

                    }

                }

            }

        }

    }

    NSLog(@"Check failed.");

    return @"";

}

NSAttributedString with fonts, paragraph Style, line spacing using NSMutableAttributedString

// create a Attributed string and adding different parameters like font, paragraph Style, etc

    // Create UIFont -

    UIFont *systemFont = [UIFont fontWithName:@"HelveticaNeue-Light" size:17.0];

    // Create a paragraphStyle -

    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];

    paragraphStyle.maximumLineHeight = 45;

    paragraphStyle.minimumLineHeight = 30;

    paragraphStyle.lineSpacing = 15;

    paragraphStyle.lineHeightMultiple = 10;

    

    // create a dictionary of Attributed -

    NSDictionary * fontAttributes = [[NSDictionary alloc] initWithObjectsAndKeys:systemFont,  NSFontAttributeName,NSParagraphStyleAttributeName,paragraphStyle, nil];

    

    // create a Attributed  string and adding parameters dictionary-

    NSMutableAttributedString *libTitle = [[NSMutableAttributedString alloc] initWithString:@"Hello there, \n" attributes:fontAttributes];

    

    // create second Attributed  string with different font-

    UIFont *subTextFont = [UIFont fontWithName:@"HelveticaNeue-Thin" size:15.0];

    NSDictionary * subTitlefontAttributes = [[NSDictionary alloc] initWithObjectsAndKeys:subTextFont, NSFontAttributeName,, nil];

    NSMutableAttributedString *subTitleString = [[NSMutableAttributedString alloc] initWithString:@"MacOS & iOS developments tips" attributes: subTitlefontAttributes];

    

    // Append Attributed string and create a single string-

    [libTitle appendAttributedString: subTitleString];

    // Set Attributed string on the label

    [self.myLabel setAttributedText:libTitle];

    

Programmatically trigger UIButton action . Calling Method from button @selector.

- (void)sendActionsForControlEvents:(UIControlEvents)controlEvents

Parameters:  controlEvents 

A bitmask whose set flags specify the control events for which action messages are sent. See Control Events for bitmask constants.

Description:Sends action messages for the given control events.UIControl implements this method to send all action messages associated with controlEvents, 

repeatedly invoking sendAction:to:forEvent: in the process. 

The list of targets and actions it looks up is constructed from prior invocations of addTarget:action:forControlEvents:.

Eg:

To call a method  MySecretMethod in newViewController 

[newViewController.button  addTarget: self 

                                              action: @selector (MySecretMethod)  

                                              forControlEvents:  UIControlEventTouchUpInside];

Method 1: declare MySecretMethod in .h of newViewController and call it

 by its object (so it wont be secret as can be accessed from anywhere.)

                 [newViewController MySecretMethod];

Method 2: declare button in .h of newViewController and call button action using following statement

[newViewController.button sendActionsForControlEvents: UIControlEventTouchUpInside];

Looping SuperView 

You can add or change the button action by looping superview view using addTarget:action:forControlEvents:

for(UIButton *aButton in self.view.subviews){

        if([aButton isKindOfClass:[UIButton class]]){

            [aButton addTarget: self 

                     action:@selector(buttonClick:) 

                     forControlEvents: UIControlEventTouchUpInside];

             }

    }

Read More:

UIButton

UIControl