Is there a better way of checking if a gameObject has a component?

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Am doing this:

if (previousObject.GetComponent() != null) { correctPos = previousObject.GetComponent(); }

But am getting the component twice. Is there a way to just check and have? Maybe is not that bad if I do this in awake or start, but it would be useful to know.

Answer 1

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Answer by SirPaddow · Jun 05, 2019 at 06:21 AM

 Collider component = previousObject.GetComponent<Collider>();
 if (component != null)
 {
     correctPos = component;
 }

[EDITED] Removed incorrect part of the answer mentionning the "??" operator. see @Hellium comment below.

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Feref2 · Jun 07, 2019 at 12:28 AM 0

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Thanks for the answer. Now am having a similar problem, and I want to know if the ?? also works. If int id != 0 { previousBaseId = id - 1;} So am doing this because the id needs to be at least 1 to get a 0 or a positive number as a result, else it should stay 0. If it´s 0 and subtracts, the id is wrong. I think this creates an error, but anyway, does the ?? work if is not posive and not just not null?

SirPaddow Feref2 · Jun 07, 2019 at 08:11 AM 0

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I'm not sure I understand your question, but in any case the "??" wont work with ints.

The operator ?? checks if the first value is null, but primitive types (such as int) are never null. If you try it, you will get a compiler error.

Hellium Feref2 · Jun 07, 2019 at 08:16 AM 0

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You will need the ternary operator to do what you want.

 int result = (condition) ? a : b;

which can be translated as follow:

 int result ;
 if( condition )
    result = a ;
 else
   result = b ;

In your case : int result = (id > 0) ? id - 1 : id ;

But more simply: if( id > 0 ) id--;

Hellium · Jun 07, 2019 at 07:29 AM 1

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The null-coalescing operator (`??`) does not work with Unity objects as indicated in this Unity blog post because it really checks against null. However, Unity does something special with the == operator.

Feref2 Hellium · Jun 12, 2019 at 09:01 PM 0

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Thanks now am using the ternary operator. Also, I found out that the 2nd condition in an if stament is not checked if the previous was true with OR: if (id == 0 || previousObject[id - 1].transform.localScale.x >= 1)

By the way, I was using the ?? solution, and I think it didn´t gave me any errors...?

SirPaddow · Jun 07, 2019 at 08:05 AM 1

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@Hellium is right, I didn't know that and didn't check it... $$anonymous$$y bad.

tormentoarmagedoom SirPaddow · Jun 07, 2019 at 08:36 AM 0

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Now is perfect, thanks @SirPaddow

Bye :D

Is there a better way of checking if a gameObject has a component?

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