As with traditional programming, we need to avoid errors in our code that can occur from trying to access null variables. In Blueprints, there are a few ways in which we can make sure a variable is valid before using it:
Depending on the context, we may just need true or false (uncommon, but may be required in an if statement before a function call, for example).
The second method uses an IsValid function call with two outputs. Both of these can be found by typing valid in the search box.
The third method, which I prefer, is to use a Validated Get, which can be created by right-clicking on a normal Get node and clicking on Convert to Validated Get. This is essentially the same as the second method, but keeps the code cleaner:
Using a validated GET is the same as this snippet of code:
if ( MyActorReference != null ) { // This is the Is Valid output. } else { // This is the Is Not Valid output. }
The Is Valid output ensures that the MyActorReference variable isn't null, and you won't get any errors trying to access its variables and functions: