Apex coding error: Method does not exist or incorrect signature

Question

I'm relatively new to apex, so maybe someone can tell me what I'm doing wrong with this code here. I'm trying to get a trigger to fire when I create a new object. I've created a separate class that it will make a call to.

trigger LearningTriggers on le_Object__c (after insert, after update) {
    if(Trigger.isAfter && (Trigger.isInsert || Trigger.isUpdate)){
        TestingTrigger t = new TestingTrigger();
        t.changeObject(Trigger.new, Trigger.old);
    }
}

This is the method in the class that I am calling with the trigger code.

public with sharing class TestingTrigger {
    public void changeObject(le_Object__c[] newObj, le_Object__c[] oldObj){
        //some code here
    }
}

For some reason, this line in the trigger code "t.changeObject(Trigger.new, Trigger.old);" is throwing this error "Save error: Method does not exist or incorrect signature: [TestingTrigger].changeObject(LIST).

It looks like there might be something wrong with the call to the method, but I'm not sure. I know the name of the method and the number of parameters in the call is correct. Can anyone tell me what's going on here? Is there something that I'm missing?

It seams that a file with TestingTrigger is not saved. Refresh it and take a look what you get on server. — Andrii Muzychuk

Sam Sam · Accepted Answer · 2013-05-26T04:33:27

Make the changeObject method a static method

 public static void changeOject(list<le_object__c> newList, list<le_object__c> oldList){
  }

And you do not need to instantiate the class in the trigger, as the method is now static you can directly call the method something like this:

TestingTrigger.changeObject(trigger.new, trigger.old);

Apex coding error: Method does not exist or incorrect signature

1 Answers