Math Drill: Refactoring into a subview

I next made several refactorings for the math drill project.

Protocols instead of classes

 Instead of passing entire classes around, I made some protocols that define behavior and create an id parameter for this.   This gets rid of several 'forward class' declarations, and allows for classes to be included easier.

Protocol 1 is for the math definition itself, it has the commonly exposed functions that are needed outside.

The next one is for the controller.  It defines the action of selecting a choice (we don't care what it is), and switching to an arbitrary problem.

//The first protocol defines a class that can define a set of problems and

// also select choices.

@protocol MathProblemDefinition

// Called when this problem is seleced.

- (IBAction) setFocus:(id) choice;

// called to indicae that this problem has a choice selected.

- (bool) setChoice:(int) choice;

- (NSMutableArray*) calculateChoices:(int) maxNumChoices;

@end

// A protocol for a controller that this view will notify when it comes into

// focus.

@protocol MathProblemController

- (void) choiceDone;

- (void) setProblemNumber:(int) problemNumber;

@end

A dedicated view controller for the problem display

I defined a separate class for the problem display.  This allows less coupling, and make the actual controller simpler.   I later want to make the UI better.

Header:

@interface MathChoiceDisplay : UIViewController {

NSSet *choices;

id<MathProblemController> controller;

id<MathProblemDefinition> problem;

}

@property (nonatomic,retain) id problem;

@property (nonatomic,retain) NSSet *choices;

@property (nonatomic,retain) id controller;

- (id) initWithChoices:(UIView *) targetView choices:(NSArray*)possibleChoices;

- (IBAction) buttonChosen:(id)sender;

Implementation:

}

- (id) initWithChoices:(UIView *) targetView choices:(NSArray*)possibleChoices

{

int width=targetView.frame.size.width;

int height=targetView.frame.size.height;

self.view =[[UIView alloc] initWithFrame:CGRectMake(targetView.frame.origin.x-width, targetView.frame.origin.y-height,

targetView.frame.size.width*3, targetView.frame.size.height*3)];

self.view.center=targetView.center;

self.view.backgroundColor=[UIColor colorWithRed:0 green:0 blue:0 alpha:0];

int row=0;

int column=0;

[self.view becomeFirstResponder];

self.view.userInteractionEnabled=true;

NSLog(@"Num Choices %d",[possibleChoices count]);

for (NSNumber *value in possibleChoices)

{

if ((row==1) &&(column==1))

column++;

UIButton *button=[[UIButton alloc]init] ;

button.tag=[value intValue]; 

button.frame=CGRectMake(column*width,height*row,width,height);

button.backgroundColor=[UIColor redColor];

button.userInteractionEnabled=true;

[button setTitle:[value stringValue] forState:UIControlStateNormal];

[button addTarget:self action:@selector(buttonChosen:) forControlEvents:UIControlEventTouchUpInside];

[self.view addSubview:button];

column++;

if (column>=3)

{

column=0;

row++;

}

}

[self becomeFirstResponder];

return self;

}

- (IBAction) buttonChosen:(id)sender

{

UIButton *button=(UIButton*) sender;

int choice=button.tag;

[problem setChoice:choice];

[controller choiceDone ];

 

 

}

 

@end

Usage: This becomes much cleaner and allows it to be seen what is doing.

- (void) setProblemNumber:(int) problemNumber

{

NSLog(@"Choosing problem %d",problemNumber);

MathProblem *oldProblem=[self getProblemAtIndex:currentProblem];

if (oldProblem!=nil)

oldProblem.view.alpha=0.5;

if (currentProblemDisplay!=nil)

{

[currentProblemDisplay.view removeFromSuperview];

self.currentProblemDisplay=nil;

}

currentProblem=problemNumber;

MathProblem *problem=[self getProblemAtIndex:problemNumber];

if (problem==nil)

return;

self.currentProblemDisplay= [[MathChoiceDisplay alloc] initWithChoices:problem.view choices:[problem calculateChoices:8]]; 

self.currentProblemDisplay.problem=problem;

self.currentProblemDisplay.controller=self;

[self.displayArea addSubview:currentProblemDisplay.view];

problem.view.alpha=1;

}

I also refactored the controller to make the 'selecting math problem based on index' easier:

- (MathProblem*) getProblemAtIndex:(int) index

{

MathProblem *returnValue=nil;

if ((index>=0)&&(index<[currentProblems count]))

{

returnValue=(MathProblem*)[currentProblems objectAtIndex:index];

}

return returnValue;

}