Setting Property upon Initialization

Question

I am creating an instance of a view controller and then presenting it modally on another view as such:

[viewController receiveNumber1:number1 andNumber2:number2];
[viewController setModalTransitionStyle:UIModalTransitionStyleCrossDissolve];
[self presentModalViewController:viewController animated:YES];

What I would like to do is set two properties within this new view controller upon initialization.

I can do this by calling a custom method like (somethings are int variables here):

[viewController methodProperty1:something1 andProperty2:something2];

However, I really need to set those properties right upon initialization because the content of the new view is dependent on those numbers.

Is there a way to pass on information to a new view while it is being initialized? Something like:

[[UIViewController alloc] initWithValue1:something1 andValue2:something2];

Also, I do not understand why

CustomViewController *view = [[CustomViewController alloc] init];
view.property = newValue; / [view setProperty:newValue];

does not work in this configuration, meaning the properties' values do not change. I can call methods within the new view and set its properties that way but not set the properties directly?

I'm sorry if these are lame questions, but I am sort of a beginner.

Thanks a bunch!

Answer 1

1. view.property = newValue and [view setProperty:newValue] are equivalent terminology.
2. You can implement one or multiple custom initialization methods for your view controller there is nothing that should stop from doing so. Have a look to the official doc to make sure you respect a couple of rules of how you should implement your custom initializer.

Your code snippet:

-(id)initWithValue1:(NSInteger)value1 andValue2:(NSInteger)value2
{
    if (self = [super init])
    {
        _firstValue = value1;
        _secondValue = value2;
        return self;
    }
    else return nil; // or handle the error
}

Answer 2

In your CustomViewController.h, define two properties you want set and an initialization method, for example:

@property (nonatomic, assign) NSInteger firstValue;
@property (nonatomic, assign) NSInteger secondValue;

-(id)initWithFirstValue:(NSInteger)value1 andSecondValue:(NSInteger)value2;

Then, in your CustomViewController.m, implement the method you have declared earlier:

-(id)initWithFirstValue:(NSInteger)value1 andSecondValue:(NSInteger)value2
{
    self = [super init];
    if (self)
    {
        // Supposing you haven't synthesized your property and you are using
        // latest Xcode build, instance variable are automatically created
        _firstValue = value1;
        _secondValue = value2;
    }
    return self;
}

Finally, you can allocate your controller using this line of code:

CustomViewController *controller = [[CustomViewController alloc] initWithFirstValue:value1ToSet andSecondValue:value2ToSet];

Some final advice
When you implement your custom initialization method, you should properly choose which init has to be called on super.
For instance, I prefer calling self = [super initWithFrame:CGRectZero]; if my controller is a subclass of UIViewController, or self = [super initWithStyle:UITableViewStylePlain]; if it is a subclass of UITableViewController.
There are other custom init method but you can find other information reading documentation about your custom controller superclass.