数组中的函数名称

I have a problem in calling a function that the name is being stored in an array.

class tempClass {
   function someFunction() {
      $tempArray = array('functionName' => 'tempFunction');
      $tempArray['functionName']();
   }

   function tempFunction() {
      echo "inside function";
   }
}

It gives me an error:

"Fatal error: Call to undefined function tempFunction() in /..... line..".

Line number is the line where the function is being called, $tempArray['functionName']();

But if called the method_exists(), it shows that the method is exists. It is very confusing. Can anyone please help me out? Thanks.

Use call_user_func() , like this:

call_user_func($tempArray['functionName']);

UPDATE:
As you want to call a method of a class from inside that class, use the following instead:

call_user_func(array($this, $tempArray['functionName']));

See working demo

Well you ask if the method exists inside the class or object, but you call it without that scope. That won't work...

Try this instead:

call_user_method($tempArray['functionName'],$this);

Just saw that call_user_method() is depreciated. Use call_user_func() as answered by Nelson instead.