null objects

Unity Engine
1

I am totally confused, I want to let my script know, is there enemy in the scene?
Here is what I’m trying to use

var enemy : GameObject[];

function Update () {
	enemy  = GameObject.FindGameObjectsWithTag ("Enemy");	
	
        if(enemy == null){
	print ("there is no enemy");
	}
	
	if (enemy != null){
	print ("there is enemy somewhere");
	}
}

but it’s always print me “there is enemy somewhere” even if there is no…

2

Try printing out the contents of the enemy array?

3

It’s just a supposition but I guess the method returns an empty array which is quite different from null.
You should check the length of the Array instead of testing if enemy is null.

4

How to do that?

var enemy : GameObject[];
var enemyArray = new Array();

function Update () {
	enemy  = GameObject.FindGameObjectsWithTag ("Enemy");	
	enemyArray.Add (enemy);
//	print (enemyArray);
	if(enemyArray == null){
	print ("there is no enemy");
	}
	
	if (enemyArray != null){
//	print (enemy);
	print ("there is enemy somewhere");
	}
}

got the same…

5 
enemy = GameObject.FindGameObjectsWithTag("Enemy");
if (enemy.Length > 0) {
    // do something
}
6

Ok, this is works too:

function Update () {
	enemy  = GameObject.FindGameObjectsWithTag ("Enemy");	
	enemyArray.Add (enemy);
	enemyArray.length = enemy.Length;
//	print (enemyArray.length);
	if(enemyArray.length <= 0){
	print ("there is no enemy");
	}
	
	if (enemyArray.length > 0){
//	print (enemy);
	print ("there is enemy somewhere");
	}
}

thx all

7

FindGameObjectsWithTag returns a GameObject[ ] so there’s no need for another array on top of that. Just check if the length of enemy is greater than 0. If it is, then you have enemies in your scene.

8

The docs seem to need this updated. I quote, “Returns null if no GameObject was found.” I don’t know where to start looking for a way to “report a bug” about the documents.

9

The bug reporter app.

–Eric

10

Thank you Eric5h5. I should have thought of that. It has been reported.