Check device OS version

Alertnative 1 :
NSArray *vComp = [[UIDevice currentDevice].systemVersion componentsSeparatedByString:@"."];

           
if ([[vComp objectAtIndex:0] intValue] >= 7) {

      // OS 7 code here

}

Alertnative 2 :
NSString *reqSysVer = @"7.0";
NSString *currSysVer = [[UIDevice currentDevice] systemVersion];

    

if ([currSysVer compare:reqSysVer options:NSNumericSearch] != NSOrderedAscending) {

     // OS 7 code here

}

Custom ActivityIndicator

//Display an Activity Indicator

-(void) displayActivityIndicator {

    // Set position for activityIndicator

    [self setActivityIndicatorPosition];

    

    [waitView setImage:[UIImage imageNamed:@"WaitScreen.png"]];

    

    activityIndicator= [[UIActivityIndicatorView alloc]

                        initWithActivityIndicatorStyle: UIActivityIndicatorViewStyleWhiteLarge];

    

    [activityIndicator setFrame:CGRectMake(86,30,30,30)];

    [activityIndicator startAnimating];

    

    [waitView addSubview: activityIndicator];

    

    [self.view] addSubview:waitView];

    

    [activityIndicator startAnimating];

    

    //Ignore interaction for background activities

    [[UIApplication sharedApplication] beginIgnoringInteractionEvents];

}

#pragma mark -

#pragma mark setActivityIndicatorPosition

-(void) setActivityIndicatorPosition {

       

    CGRect screenSize = [[UIScreen mainScreen] bounds];      

    

     if( ([UIApplication sharedApplication].statusBarOrientation == UIInterfaceOrientationPortrait) || ( [UIApplication sharedApplication].statusBarOrientation == UIInterfaceOrientationPortraitUpsideDown)) {

        

        [waitView setFrame:CGRectMake(x,y,203,73)];

    }

    

    if(([UIApplication sharedApplication].statusBarOrientation == UIInterfaceOrientationLandscapeLeft ) || ([UIApplication sharedApplication].statusBarOrientation == UIInterfaceOrientationLandscapeRight)) {

                

         [waitView setFrame:CGRectMake(x1,y1,203,73)];

    }    

}

//Hide Activity Indicator

-(void) hideActivityIndicator {

    

    //Hide waitView

    [waitView setImage:[UIImage imageNamed:nil]];

    [activityIndicator stopAnimating];

    

    if ([[UIApplication sharedApplication] isIgnoringInteractionEvents]) {

        

        // Start interaction with application

        [[UIApplication sharedApplication] endIgnoringInteractionEvents];

    }

       

}

                                 

 

NSUserDefault usage

 //Set NSUserDefault

NSString *somePersistantValue = @"null";

    

[[NSUserDefaults standardUserDefaults] setObject:somePersistantValue forKey:@"keyName"];

[[NSUserDefaults standardUserDefaults] synchronize];

 //Get NSUserDefault

NSString *fetchPersistantValue = [[NSUserDefaults standardUserDefaults] objectForKey:@"keyName"]; 

Set notification for Orientation

//Set Notification on Orientation change

[[NSNotificationCenter defaultCenter] addObserver:self  selector:@selector(orientationChanged:) name:UIDeviceOrientationDidChangeNotification  object:nil];

//  Handle orientation change

- (void)orientationChanged:(NSNotification *)notification {

    ...

}

Using camera / gallery of device

 UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];

        

//camera selection

if(buttonIndex == 0){

if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]){

                

imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;

imagePicker.delegate = self;

                

[self presentViewController:imagePicker animated:YES completion:nil];                

}

else {

                

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Alert" message:NSLocalizedString(@"DeviceItem", @"") delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil];

                

[alert show];

}

}       

else if(buttonIndex == 1) {   //gallery selection

            

imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;

            

   imagePicker.delegate=self;

   [self presentViewController:imagePicker animated:YES completion:nil];

}

Execute code in background

// Fetch legend details task in background

                 dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);

                 dispatch_after(popTime, dispatch_get_main_queue(), ^(void){

                     

                     // Perform task here

                 });

Check device orientation

UIInterfaceOrientation orientation = [UIApplication sharedApplication].statusBarOrientation;

 if ((orientation == UIInterfaceOrientationLandscapeLeft) || (orientation == UIInterfaceOrientationLandscapeRight)) {

     //Landscape mode

}

 else if ((orientation == UIInterfaceOrientationPortrait) || (orientation == UIInterfaceOrientationPortraitUpsideDown)) {

     //Portrait mode

}

Animate UItableView while reloading table content

 //Reload tableView with animation

    [self.tableView reloadSections:[NSIndexSet indexSetWithIndex:0] withRowAnimation:UITableViewRowAnimationRight];  

Options :

UITableViewRowAnimationFade, UITableViewRowAnimationRight, UITableViewRowAnimationLeft, UITableViewRowAnimationTop, UITableViewRowAnimationBottom, UITableViewRowAnimationNone, UITableViewRowAnimationMiddle

Fetch gzip format response

@try {

        NSURL *url = [NSURL URLWithString:strURL];

        

        NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url

                                                               cachePolicy:NSURLRequestReloadIgnoringLocalCacheData  timeoutInterval:180.0];

        

        [request setHTTPMethod:@"POST"];

        [request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];

        

        //Set GZIP format

        [request setValue:@"gzip" forHTTPHeaderField:@"Accept-Encoding"];

        

        //Set Authorization request

        if([basicAuthRequired caseInsensitiveCompare:@"Yes"] ==  NSOrderedSame) {

            

            NSString *authStr = [NSString stringWithFormat:@"%@:%@", username, password];

            NSData *authData = [authStr dataUsingEncoding:NSASCIIStringEncoding];

            NSString *authValue = [NSString stringWithFormat:@"Basic %@", [authData base64EncodingWithLineLength:80]];

            

            [request setValue:authValue forHTTPHeaderField:@"Authorization"];

        }

        

        NSURLResponse *response = NULL;

        NSError *requestError = NULL;

        

        //NSURLConnection will automatically decode gzipped response

        NSData *responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response

                                                                 error:&requestError];

        

        NSError *errorSuccess=nil;

        

        NSMutableDictionary  *dictionary = [[NSMutableDictionary alloc]

                                            initWithDictionary:[NSJSONSerialization JSONObjectWithData:responseData options:kNilOptions error:&errorSuccess]];

        

        if (errorSuccess) { //Handle error if dictionary failed to generate

            [self showSecureServiceAlert];

        }

        

        return dictionary;

    }

    @catch (NSException *exception) {

        // Handle exception

        NSLog(@"Exception in fetchURLContent function");

    }

Create function with multiple parameters

 //Create function with multiple parameter

 [self createNewFileStructure : url : uniqueID : authentication : dictionary];

#pragma mark - createNewFileStructure

-(void) createNewFileStructure : (NSString *) url : (int) uniqueID  : (NSString *) authentication : (NSMutableDictionary *) dictionary {

    // Function body. Use parameters here

}

Waiting label strip on top position of device with animation

 //Show an Wait indicator

 [self showHelpLabel];

#pragma mark -

#pragma mark showHelpLabel

-(void)showHelpLabel {  // Show instructions

    

    infoLabel = [[UILabel alloc] init];

    infoLabel.text = [NSString stringWithFormat:NSLocalizedString(@"PleaseWait", @"")];

    

    //Check OS version and set image for Toolbar button

    reqSysVer = @"7.0";

    currSysVer = [[UIDevice currentDevice] systemVersion];

    

    //Check OS version and set image for Toolbar button

    if ([currSysVer compare:reqSysVer options:NSNumericSearch] != NSOrderedAscending) {        

        [infoLabel setFrame:CGRectMake(0, 60,self.mapView.frame.size.width ,50)];

    }

    else {

        [infoLabel setFrame:CGRectMake(0, 0,self.mapView.frame.size.width ,50)];

    }

    

    infoLabel.numberOfLines =2;

    

    [infoLabel setBackgroundColor:[UIColor blackColor]];

    infoLabel.textAlignment = UITextAlignmentCenter;

    [infoLabel setTextColor:[UIColor whiteColor]];

    infoLabel.autoresizesSubviews = TRUE;

    infoLabel.autoresizingMask=UIViewAutoresizingFlexibleWidth;

    [self.mapView  addSubview:infoLabel];

    

    [UIView beginAnimations:@"fade" context:NULL];

[UIView setAnimationDuration:2];

[UIView setAnimationDelegate:self];

    [UIView setAnimationDidStopSelector:@selector(reverseAnimation)];

infoLabel.alpha = 0.0;

infoLabel.alpha = 1.0;

    

[UIView commitAnimations];

}

#pragma mark -

#pragma mark reverseAnimation

-(void)reverseAnimation {

    

    [UIView beginAnimations:@"fade" context:NULL];

[UIView setAnimationDuration:2];

[UIView setAnimationDelegate:self];

    

    [UIView setAnimationDidStopSelector:@selector(removeLabel)];

    

infoLabel.alpha = 1.0;

infoLabel.alpha = 0.0;

    

[UIView commitAnimations];

}

#pragma mark -

#pragma mark HelpLabel

-(void)removeLabel { // Remove instructions

    

    [infoLabel removeFromSuperview];

}

Restrict user from entering certain number of characters in UITextField

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string { // Restrict user in entering 25 characters in UITextField

          

    if (textField.tag==111) {

        

        const char * _char = [string cStringUsingEncoding:NSUTF8StringEncoding];

        int isBackSpace = strcmp(_char, "\b");

        

        if (isBackSpace == -8) {

            NSLog(@"isBackSpace");

            return YES; // is backspace

        }

        else if (textField.text.length <= 25 && range.length == 0) {

            return YES;

        }

    }

           

    return NO;

}

Change color of button in UIActionSheet

- (void)willPresentActionSheet:(UIActionSheet *)actionSheet {

    

    if ([[[UIDevice currentDevice] systemVersion] intValue]>=7) { // Change color of button in actionsheet for iOS 7

        

        if (actionSheet==actionSheetCustom) {

                      

          [[actionSheet layer] setBackgroundColor:[UIColor whiteColor].CGColor];

        

          for (UIView *subview in actionSheet.subviews) {

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

                 UIButton *button = (UIButton *)subview;

                

                [button setBackgroundColor:[UIColor colorWithPatternImage:[UIImage imageNamed:@"Login-Background.png"]]];

              }

          }

            

        }

    }

}

Check disk space capacity

 //Invoke freeDiskspace function

 [self freeDiskspace];

//Check for Disk Space capacity

- (void)freeDiskspace {

    

    totalSpace = 0;

    totalFreeSpace = 0;

    

    __autoreleasing NSError *error = nil;

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

    NSDictionary *dictionary = [[NSFileManager defaultManager] attributesOfFileSystemForPath:[paths lastObject]

                                                                            error: &error];

        

    if (dictionary) {

        

        fileSystemSizeInBytes = 0;

        freeFileSystemSizeInBytes = 0;

        

        fileSystemSizeInBytes = [dictionary objectForKey: NSFileSystemSize];

        freeFileSystemSizeInBytes = [dictionary objectForKey:NSFileSystemFreeSize];

        // freeFileSystemSizeInBytes = [NSNumber numberWithInt:1293408];

        

        NSLog(@"fileSystemSizeInBytes : %@  freeFileSystemSizeInBytes : %@ ",fileSystemSizeInBytes,freeFileSystemSizeInBytes);

        

        totalSpace = [fileSystemSizeInBytes unsignedLongLongValue];

        totalFreeSpace = [freeFileSystemSizeInBytes unsignedLongLongValue];

                      

        NSLog(@"Memory Capacity of %llu MB with %llu MB Free memory available.", ((totalSpace/1024ll)/1024ll), ((totalFreeSpace/1024ll)/1024ll));

        

    } else {

        

        NSLog(@"Error Obtaining System Memory Info: Domain = %@, Code = %d", [error domain], (int)[error code]);

    }

}

Delete an UIAlertView window (if exists)

//Code to delete an Alert Window

for (UIWindow *window in [UIApplication sharedApplication].windows) {

                        

     NSArray *subviews = window.subviews;

                       

     if ([subviews count] > 0) {

                         

          for (int k=0; k<[subviews count]; k++) {

                                

             BOOL alert = [[subviews objectAtIndex:k] isKindOfClass:[UIAlertView class]];

                                

             if (alert) {

                 NSLog(@"alert exists");

                                  

                 // Delete an Alert                                    

               [(UIAlertView *)[subviews objectAtIndex:k] dismissWithClickedButtonIndex:[(UIAlertView *)[subviews objectAtIndex:k] cancelButtonIndex] animated:NO];

                                    

                break;

             }

                                

          }

      }

 }

Email ID Validation

//Regex for Validating EmailID

-(BOOL) validateEmailIDfromString : (NSString *) s {

    

NSString * emailregexString = @"\\b([a-zA-Z0-9%_.+\\-]+)@([a-zA-Z0-9.\\-]+?\\.[a-zA-Z]{2,3})\\b" ;     

    

NSPredicate *regexText = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",emailregexString] ;

return ([regexText evaluateWithObject:s]);

}

if(![self validateEmailIDfromString:txtLogin]) {  

   // Invalid email ID 

}

Animate ScrollView on editing UITextField

//Declare in implementation file

static const CGFloat KEYBOARD_ANIMATION_DURATION = 0.3;

static const CGFloat MINIMUM_SCROLL_FRACTION = 0.2;

static const CGFloat MAXIMUM_SCROLL_FRACTION = 0.8;

static const CGFloat PORTRAIT_KEYBOARD_HEIGHT = 216;

//static const CGFloat LANDSCAPE_KEYBOARD_HEIGHT = 162;

#pragma - UITextField Delegates

- (void)textFieldDidBeginEditing:(UITextField *)textField {

    

    //Perform Animation during Keyboard show and Hide

    CGRect textFieldRect = [self.view.window convertRect:textField.bounds fromView:textField];

    CGRect viewRect = [self.view.window convertRect:self.view.bounds fromView:self.view];

    

    CGFloat midline = textFieldRect.origin.y + 0.5 * textFieldRect.size.height;

    CGFloat numerator = midline - viewRect.origin.y - MINIMUM_SCROLL_FRACTION * viewRect.size.height;

    

    CGFloat denominator = (MAXIMUM_SCROLL_FRACTION - MINIMUM_SCROLL_FRACTION) * viewRect.size.height;

    CGFloat heightFraction = numerator / denominator;

    

    if (heightFraction < 0.0) {

        heightFraction = 0.0;

    }

    else if (heightFraction > 1.0) {

        heightFraction = 1.0;

    }

    

    animatedDistance = floor(PORTRAIT_KEYBOARD_HEIGHT * heightFraction);

    

    CGRect viewFrame = self.view.frame;

    viewFrame.origin.y -= animatedDistance;

    

    [UIView beginAnimations:nil context:NULL];

    [UIView setAnimationBeginsFromCurrentState:YES];

    [UIView setAnimationDuration:KEYBOARD_ANIMATION_DURATION];

    

    [self.view setFrame:viewFrame];

    

    [UIView commitAnimations];

}

- (BOOL)textFieldShouldEndEditing:(UITextField *)textField {

    

    return YES;

}

- (BOOL)textFieldShouldReturn:(UITextField *)textField {

    

    [textField resignFirstResponder];

    return YES;

}

- (void)textFieldDidEndEditing:(UITextField *)textField {

    

    CGRect viewFrame = self.view.frame;

    viewFrame.origin.y += animatedDistance;

    

    [UIView beginAnimations:nil context:NULL];

    [UIView setAnimationBeginsFromCurrentState:YES];

    [UIView setAnimationDuration:KEYBOARD_ANIMATION_DURATION];

    

    [self.view setFrame:viewFrame];

    

    [UIView commitAnimations];

}

Reverse content of Array

/ Reverse the content of Array so as to display recent

// value on top of stack

-(NSArray *) reverseArray : (NSArray *) myArray {

    

    return [[myArray reverseObjectEnumerator] allObjects];

}

Simple way to detect empty field

// Detect empty fields

-(BOOL) detectEmptyTextFields {

    

    UITextField *temp = (UITextField *)[self.Control1 viewWithTag:12];

    

    //Remove whitespaces if any in string

    NSCharacterSet *whitespace = [NSCharacterSet whitespaceCharacterSet];

    NSString *trimmedString = [temp.text stringByTrimmingCharactersInSet:whitespace];

    

    NSLog(@"Value of the text field is %@",trimmedString);

    

    if (([trimmedString isEqualToString:@""])) {

        return YES;

    }

    

    NSLog(@"temp.text : %@",temp.text);

    

    if ([temp.text isEqualToString:@""] || temp.text==nil) {

        return YES;

    }

    

    return NO;

}

Compute height on control (eg.UILabel) based on text

//Compute height for label based on text

CGSize labelStringSize = [self labelStringSize:lblInput.text]; 

cell.lblInput.frame = CGRectMake(x, y, 160,labelStringSize.height);

-(CGSize)labelStringSize : (NSString *) strInput { // Detemine height based on text

    

    UILabel *tempLabel = [[UILabel alloc] init];

    tempLabel.lineBreakMode = UILineBreakModeWordWrap;

    

    tempLabel.text = [NSString stringWithFormat:@"%@",strInput];

    CGSize labelStringSize = [tempLabel.text sizeWithFont:tempLabel.font constrainedToSize:CGSizeMake(143, 9999) lineBreakMode:tempLabel.lineBreakMode];

    

    return labelStringSize;

}