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Android Build a Simple Android App (retired 2014) Getting Started with Android Adding an OnClickListener to a Button

Posted by Baris Derin
Baris Derin
Courses Plus Student 443 Points

Why final is only added for TextView?

Hi,

Why final is required only for TextView but not Button view?

Thanks

2 Answers

Calvin Nix
Calvin Nix
43,828 Points
Calvin Nix
Calvin Nix
43,828 Points

Hey Baris,

"The Onclick method must refer to the same method as long as it exists. You can't make it update a different textview by reassigning the answerlabel variable to some other textview"

Final makes sure that the variable always points to the object that it was first assigned to. If you try to change this then you will receive errors.

Baris Derin
PLUS
Baris Derin
Courses Plus Student 443 Points
Baris Derin
Baris Derin
Courses Plus Student 443 Points

Hi Calvin,

So onclick requires all variables declared outside the function to be final, right?

Calvin Nix
Calvin Nix
43,828 Points
Calvin Nix
Calvin Nix
43,828 Points

Hey Baris,

Pretty much. It just protects the variable from be re-assigned.

Eclipse will let you know if it is unhappy with something though. :)