Graphics Programs Reference
In-Depth Information
Creating the TouchTracker Application
Now let's get started with your application. In
Xcode
, create a new
Empty Application
iPhone project and name it
TouchTracker
. Don't specify a
Class Prefix
and only check the
box for
Automatic Reference Counting
.
First, you will need a model object that describes a line. Create a new
NSObject
and
name it
Line
. In
Line.h
, declare two
CGPoint
properties:
#import <Foundation/Foundation.h>
@interface Line : NSObject
@property (nonatomic) CGPoint begin;
@property (nonatomic) CGPoint end;
@end
In
Line.m
, synthesize the properties:
#import "Line.h"
@implementation Line
@synthesize begin, end;
@end
Next, create a new
NSObject
called
TouchDrawView
. In
TouchDrawView.h
,
change the superclass to
UIView
. Also, declare two collection objects: an array to hold
complete lines and a dictionary to hold lines that are still being drawn. You'll see why
we're using different collection objects shortly.
#import <Foundation/Foundation.h>
@interface TouchDrawView : NSObject
@interface TouchDrawView : UIView
{
NSMutableDictionary *linesInProcess;
NSMutableArray *completeLines;
}
- (void)clearAll;
@end
Now you need a view controller to manage an instance of
TouchDrawView
in
TouchTracker
. Create a new
NSObject
subclass named
TouchViewController
. In
TouchViewController.h
, change the superclass to
UIViewController
.
@interface TouchViewController : NSObject
@interface TouchViewController : UIViewController
