SIMPLE PROTOCOL & DELEGATE EXAMPLE

PROTOCOL & DELEGATE

two controllers

FirstViewController

SecondViewController

SecondViewController.h

@protocol SecondViewControllerDelegate;

@property (nonatomic, weak) id<SecondViewControllerDelegate> delegate;

@protocol SecondViewControllerDelegate <NSObject>

- (void)SecondViewController:(SecondViewController*)viewController

             didChooseValue:(CGFloat)value;

SecondViewController.m

-(IBAction)SecondTap:(id)sender

{

    id<SecondViewControllerDelegate> strongDelegate = self.delegate;

    

    // Our delegate method is optional, so we should

    // check that the delegate implements it

    

    if ([strongDelegate respondsToSelector:@selector(SecondViewController:didChooseValue:)]) {

        [strongDelegate SecondViewController:self didChooseValue:[sender tag]];

    }

}

FirstViewController.h

@interface FirstViewController : UIViewController<SecondViewControllerDelegate>

FirstViewController.m

-(IBAction)Add:(id)sender

{

    SecondViewController *objsecond =[[SecondViewController alloc]init];

    [objsecond setDelegate:self];

    [self.view addSubview:objsecond.view];

}

- (void)SecondViewController:(SecondViewController *)viewController didChooseValue:(CGFloat)value

{

    

    // Do something with value...

    

    // ...then dismiss the child view controller

    [viewController.view removeFromSuperview];

}

Generate PEM certificate from P12 certificate

Open terminal and go to the path where you place p12 certificate and run this complete below command:

openssl pkcs12 -in certificateName.p12 -out certificateName.pem -nodes

iOS Timer Counter !!

Here is the Timer counter simple example in which we will get seconds, minutes, and hours

Call the below method TimerCounter:

int secondsSpent;

NSTimer *timer= [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(TimeCounter) userInfo:nil repeats:YES];

- (void)TimeCounter

{

    secondsSpent ++ ;

    hours = secondsSpent / 3600;

    minutes = (secondsSpent % 3600) / 60;

    seconds = (secondsSpent %3600) % 60;

    NSLog(@"Time spent: %02d:%02d:%02d", hours, minutes, seconds);

}

iOS Local Notifications

Here we have sample code for local notification

    UILocalNotification *notification = [[UILocalNotification alloc] init];

    notification.alertBody =@"Test Message";

    notification.soundName = UILocalNotificationDefaultSoundName;

    

    [[UIApplication sharedApplication] presentLocalNotificationNow:notification];

How null,nill, and lenght 0 object can be checked ???

The simplest way to check NSNull value , nill value, and lenght =0 of object:

static inline BOOL IsEmpty(id object)

{

    return object == nil

    || ([object respondsToSelector:@selector(length)]

        && [(NSData *) object length] == 0)

    || ([object respondsToSelector:@selector(count)]

        && [(NSArray *) object count] == 0)

    || ([object respondsToSelector:@selector(count)]

        && object == nil)

    || ([object respondsToSelector:@selector(count)]

        && [ object isKindOfClass:[NSNull class]]);

    

}

How to call inline function:

 NSString *str =nil;

    

    if(!(IsEmpty(str)))

    {

        NSLog(@"The object is not null, nill,");

    }