RefactoringMoving a console app to a UI app

Refactoring

Goal: change a console app to a UI app

Principles:The main.m goes away

The local variables in the main.m file become instance variables in the new viewController.m

The functions that implemented console interactions with the user become IBAction methods for various UI components

Other classes in the console app are imported as are to the UI app

For the code for these slides, see the class web site, References->Examples->AlienRefactored

Creating the project

Create new single view projectI named mine “alienRefactored”

You get the appDelegate and the ViewController.m

Now import the class files (but not the main.m file) from the old project

FileAdd Files to “AlienRefactored”

See next slide for the dialog box

Creating the project

Check this box

Choose the files

Main.m

Does not exist in the new project (that we can see)

Open main.m from the old project.

Use codeIf there were local variables, make them instance variables

See next slide

XXXViewController.h

#import <UIKit/UIKit.h>#import "alien.h”

static const int NUMALIENS = 2;

@interface CMPViewController :UIViewController{ alien *george, *sally; double timeToHome; double timeToPlace; double theSpeed; double theDistance; id theAliens[5];}@end

Import any class you use

Make constants that you need. These must be static

XXXViewController.h

- (void) viewDidLoad{ [super viewDidLoad];// Do any additional setup after loading the view, typically from a nib.

nextIndex = 0;

}

Use viewDidLoad method to initialize variables and initialize any dynamic memory.

Designing the interface

See where the console app asked for input

printf(“enter alien name:”);scanf(“%s”, theName);printf(“enter number of eyes:”);scanf(“%d”, numEyes);printf(“enter distance to home:”);scanf(“%f”, theDistance);printf(“enter speed of ship:”);scanf(“%f”, theSpeed);

These become UITextFieldsYou’ll need IBOutlets to access them in your code.

You’ll also need a button to determine when to add this alien

Interface

Connections

Create IBOutlets for the fields

Create IBAction for the button

IBActionsFill in the action methods

−(IBAction)addAlien:(UIButton *)sender { NSString *thePlanet = _nameField.text; theSpeed = [_speedField.text doubleValue]; theDistance = [_distanceField.text doubleValue]; int numEyes = [_numEyesField.text integerValue]; george =[[alien alloc] initWithNum: numEyes andDistance: theDistance

andPlanet: thePlanet]; if (nextIndex < 5) {

theAliens[nextIndex++] = george;

NSLog(@"the next alien lives at %@ and is %f miles from home at %f speed",

((alien *)theAliens[nextIndex - 1]).planet, ((alien *)theAliens[nextIndex - 1]).distanceToHome,

((alien *)theAliens[nextIndex - 1]).speedSpaceShip); }

}

Print to the console as an error check

If you don’t explicitly @synthesis properties, their getters and setters are preceded by an underscore (‘_’)

Fix the keyboardConnect to this method from every text field

Fix the keyboard

Add the action method for the text fields

−(IBAction)didFinishEditing:(UITextField *)sender {

[sender resignFirstResponder];

}

Put in appropriate error messages

Array is full in - (IBAction)addAlien:(UIButton *)sender if (nextIndex < MAXALIENS) {

// previous code else{

// the array is fullUIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Alien Alert!" message:@"Too many Aliens!" delegate:nil cancelButtonTitle:@"Phew!" otherButtonTitles:nil]; [alert show];

}

Add more buttons

Each console option must have a component (usually a button).

Add more buttons and fields as necessary.

Hide components to minimize clutter

More ButtonsAdd components to perform other functions from the console app

Connect the new componentsI would also add

an IBOutlet for the new field.

Add bodies for the Action methods

For our “Calc Time” button

- (IBAction)calcTimeHome:(UIButton *)sender { // pick an arbitrary alien

if (nextIndex > 0){ float timeHome = [((alien *)theAliens[0])

calcTimeToHome]; // put the value into the text field_timeToHome.text = [NSString stringWithFormat:

@"%f", timeHome]; }

}

If you don’t explicitly @synthesis properties, their getters and setters are preceded by an underscore (‘_’)