Passing a Difficulty level between controllers

Question

I am looking for the best way to pass a Difficulty level between View Controllers.

At present I have this setup as a String. There are three options Easy/Medium/Hard, I know this is not the best way to do this so am looking for what would be the correct approach here.

At the moment I check the tag on the button and set a string value like below:

if (sender.tag == 10) {
    self.turnDifficulty = @"Easy";
} else if (sender.tag == 20) {
    self.turnDifficulty = @"Medium";
} else if (sender.tag == 30) {
    self.turnDifficulty = @"Hard";
}

I then pass the value over in the prepareForSegue method. What is the alternate to this approach? Although there is no issue here and this works fine, it is not very clean working with strings here.

Why do you think you have to use strings? Why not use a number? — Caleb, Jan 06 '14 at 15:22
possible duplicate of [Passing Data between View Controllers](http://stackoverflow.com/questions/5210535/passing-data-between-view-controllers) — Mick MacCallum, Jan 06 '14 at 15:24

score 4 · Accepted Answer · edited May 23 '17 at 10:25

4

One alternative to working with strings in Objective-C (indeed, in C and C++ as well) us using an enumeration:

typedef enum Difficulty {
    DIFFICULTY_EASY
,   DIFFICULTY_MEDIUM
,   DIFFICULTY_HARD
} Difficulty;

Declare this enum in a header included from all your view controllers, and use enumeration constants as if they were numeric constants. The language will ensure that the constants remain distinct, even when you choose to add more items to the enumeration.

When you declare a @property or a parameter of type Difficulty, do not use an asterisk, because enums are primitive types, not reference types. For example:

@property (nonatomic, readwrite) Difficulty difficultyLevel;

or

-(void)openWithDifficulty:(Difficulty)level;

EDIT : (thanks, Rob!)

As of Xcode 4.4, you might also use an explicit fixed underlying type, e.g.

typedef enum Difficulty : NSUInteger {
    kDifficultyEasy
,   kDifficultyMedium
,   kDifficultyHard
} Difficulty;

edited May 23 '17 at 10:25

Community

1
1

answered Jan 06 '14 at 15:18

Sergey Kalinichenko

714,442
84
1,110
1,523

When you don't assign values inside the `enum` structure, are they just automatically assigned a unique value? – hgwhittle Jan 06 '14 at 15:22
@hw731 Yes, they are. – Sergey Kalinichenko Jan 06 '14 at 15:22
3

As of Xcode 4.4, you might also use an explicit fixed underlying type, e.g. `typedef enum Difficulty : NSUInteger {kDifficultyEasy, kDifficultyMedium, kDifficultyHard} Difficulty;` – Rob Jan 06 '14 at 15:33
Would the correct process be to just create a .h file with this typedef within? – StuartM Jan 06 '14 at 15:42

score 0 · Answer 2 · answered Jan 06 '14 at 15:20

If your problem is just working with string you should declare an enumeration.

Write in a Enum.h that will be imported by all your controllers :

typedef enum
{
    EASY = 0,
    MEDIUM,
    HARD
}   DIFFICULTY;

Just for someone-who-wouldn't-know-what-this-is' information, this declare a restrictive integer type that can have only 3 values : EASY (= 0), MEDIUM (= 1), HARD (= 2).

It will be far cleaner (and better for your memory management).

Passing a Difficulty level between controllers

2 Answers2