Friday, 13 November 2015

Animation in iOS

Animations provide fluid visual transitions between different states of your user interface. In iOS, animations are used extensively to reposition views, change their size, remove them from view hierarchies, and hide them. You might use animations to convey feedback to the user or to implement interesting visual effects. 

In iOS creating the sophisticated animations doesn't require to write any drawing code.All the animation's techniques use the built in support of core animation . Both UIKit and Core animation provide support for animation .

The following UIView properties can be animated:

1) frame
2) bounds
3) backgroundColor
4) center
5) transform
6) alpha
7) contentStretch

Changing the value of these properties merely  update the properties without any animation. To animate such a change we must change  the value of these properties from animation block. 

To understand any concept properly , example is the best way to demonstrate, so here is a simple example:

Assuming we have a single View application , that contains the login form: 

userName -- UITextFiled
password -- UITextField

LogIn -- UIButton

In starting set the initial position of the view to outside the screen


-(void)viewWillAppear:(BOOL)animated{
    super.viewWillAppear(animated)
    
    username.center.x -= view.bounds.width;
    password.center.x -= view.bounds.width;

  }

In ViewDidAppear add the following code:

 -(void)viewDidAppear:(BOOL)animated{
UIView.animateWithDuration(0.5, animations: {
      // self.password.center.x += self.view.bounds.width;  
       self.username.center.x +=  self.view.bounds.width;
    })

To animate the field in we call the UIView class  method animateWithDuration(_:animations:).The animation starts immediately and animates over half a second; you set the duration via the first method parameter in the code.

We can also delay the animation:

UIView.animateWithDuration(0.5, delay: 0.6, options: nil, animations: {
        
        self.username.center.x +=  self.view.bounds.width;

    }, completion: nil)


The class method you use this time looks familiar, but it has a few more parameters to let you customize your animation:
  1. duration: The duration of the animation.
  2. delay :The amount of seconds UIKit will wait before it starts the animation.
  3. options: A bitmask value that allows you to customize a number of aspects about your animation. You’ll learn more about this parameter later on, but for now you can pass nil to mean “no options.”
  4. animations :The closure expression to provide your animations.
  5. completion: A code closure to execute when the animation completes; this parameter often comes in handy when you want to perform some final cleanup tasks or chain animations one after the other.

Animation Options:
options allow to customize the animation:

Repeating :
  •  .Repeat: Enable this option to makes your animation loop forever.
  • .Autoreverse:  Enable this option only in conjunction with .Repeat; this option repeatedly plays your animation in forward then in reverse.

    UIView.animateWithDuration(2.5, delay: 0.9, options: .Repeat | .Autoreverse , animations: {
        self.password.center.x += self.view.bounds.width
        }, completion: nil)
  }
  

Animation Easing:

To make animation more realistic, we use easing options:

You can choose from four different easing options:
  • .Linear: This option applies no acceleration or deceleration to the animation.
  • .CurveEaseIn : This option applies acceleration to the start of your animation.
  • CurveEaseOut:This option applies deceleration to the end of your animation.
  • .CurveEaseInOut:This option applies acceleration to the start of your animation and applies deceleration to the end of your animation.
   UIView.animateWithDuration(2.5, delay: 0.9, options: .Repeat | .Autoreverse | .CurveEaseIn , animations: {
        self.password.center.x += self.view.bounds.width
        }, completion: nil)
  }


References:         https://developer.apple.com/library/ios/documentation/WindowsViews/Conceptual/ViewPG_iPhoneOS/AnimatingViews/AnimatingViews.html

Friday, 6 November 2015

Print from an app

Hello,  here I am describing the different way to include printing functionality  in an iOS app .
To add printing support in an app, at a high level we create  a print job, providing either an array of ready to print images and pdf documents, a single image or pdf, an instance of built in print formatter classes or custom print page renderer.

The UIKit API includes eight classes and one formal protocol. There are two ways to include printing in an iOS app:

1) using UIActivityViewController :  This provides simple printing and do not provide any control over printing process.

2) using UIPrintInteractionController: The shared instance of this class provides the ability to specify what should happen when printing. It contains the information about the printjob(UIPrintInfo), and the size of the paper, and the area for the printed content(UIPrintPaper). It can have a reference to UIPrintInteractionControllerDelegate protocol.

To add the priting content , UIPrintInteractionController provides following ways:

1) printngItem:  to print single image or pdf document, set the printingItem property of the UIPrintInteractionController.

2) printingItems : an array of images or documents, set the printingItems property of the UIPrintInteractionController.

3) PageRenderer : provides the complete control over the page layout. To include pageRenderer, we first subclass the PrintPageRenderer and the assign the instance of it to the PrintPageRenderer property of the UIPrintInteractionController.

These properties are mutually exclusive.

The general workflow to support printing in an app is as follows:

1) get the shared instance of  UIPrintInteractionController.

2) (optional) Create a UIPrintInfo object, set attributes such as output type, job name, and print orientation; then assign the object to the printInfo property of the UIPrintInteractionController instance.

3) (optional)Assign a custom controller object to the delegate property.

4) set the one of the four property of the UIPrintInteractionController instance.

5) If the current user- interface idiom is ipad, present the printing interface to the user by calling:
      presentFromBArButtonItem:animated:completionHandler:  or
 
     presentFromRect:inView:animated:completionHandler:

If the idiom is iPhone or iPod touch, call
    presentAnimated:completionHandler:

Example:

1) In custom view controller conform the protocol UIPrintInteractionControllerDelegate

2) get the shared instance of UIPrintInteractionController:
 
     UIPrintInteractionController *printController = [UIPrintInteractionController sharedPrintController];

3) create a print job and assign it to the printInfo property of the UIPrintInteractionController instance.


          printController.delegate = self;
        
        //print info object to supply required info to prinController
        UIPrintInfo *printInfo = [UIPrintInfo printInfo];
        
        printInfo.outputType = UIPrintInfoOutputPhoto;
        printInfo.jobName = @"Print Template";
        
        //  printing info to printController

        printController.printInfo = printInfo;

4) set the pritingItem property of the UIPrintInteractionController instance.
     
     printController.printingItem = [UIImage imageNamed:@"jery1.jpeg"];

5) create a block :

   //create block to handle error
        
        void(^ completionHandler)(UIPrintInteractionController *, BOOLNSError*)=
        ^(UIPrintInteractionController *pic, BOOL completed, NSError *error){
            
            if (!completed && error) {
                NSLog(@"FAILED! Due to error in domain %@ with error code %ld", error.domain,(long)error.code);
            }
        };
6) check for userinterface and present accordingly:

if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
            NSLog(@"user interface is ipad");
            
        }else{
     [printController presentAnimated:YES completionHandler:completionHandler];
}

7) implement the delegate method;

- (void)printInteractionControllerDidFinishJob:(UIPrintInteractionController *)printInteractionController{    
    
    UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"Print Template" message:@"Your template is ready to pickup" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
    
    [alert show];
    
}


Print Directly:

Alternatively we can print directly without presenting the printing user interface. iOS 8 provides a way to do this. To direct print, conform to the UIPrinterPickerControllerDelegate,  and add the following code:

-(void)searchPrinters{
   
    if (NSFoundationVersionNumber > NSFoundationVersionNumber_iOS_7_1) {
        UIPrinterPickerController *printerPicker = [UIPrinterPickerController printerPickerControllerWithInitiallySelectedPrinter:nil];
        
        [printerPicker presentAnimated:YES completionHandler:^(UIPrinterPickerController *printer, BOOL userDidSelect,NSError * error){
         
            if (userDidSelect) {
                [UIPrinterPickerController printerPickerControllerWithInitiallySelectedPrinter:printer.selectedPrinter];
                
            printerURL = printer.selectedPrinter.URL;
                
                NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
                
                [defaults setObject:[printerURL absoluteStringforKey:@"printerURL"];
                
                [defaults synchronize];
            }
            
        }];
    }
}

-(IBAction)print:(id)sender{

NSUserDefaults * defaults = [NSUserDefaults standardUserDefaults];
                
                    self.selectedPrinter = [UIPrinter printerWithURL:[NSURL URLWithString:[defaults objectForKey:@"printerURL"]] ];
                
                    if (self.selectedPrinter) {
                        
                        [printController printToPrinter:self.selectedPrinter completionHandler:^(UIPrintInteractionController *printController, BOOL completed, NSError *error){
                        
                            if (completed) {
                                NSLog(@"priting successfully completed");
                                UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"Print" message:@"Successfully printed" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nilnil ];
                                
                                [alert show];
                            }
                            else{
                                NSLog(@"error occured while printing");
}

}




Reference:https://developer.apple.com/library/ios/documentation/2DDrawing/Conceptual/DrawingPrintingiOS/Printing/Printing.html