Yeah, the concept of "this" is fundamental to object-oriented programming, and pretty much all OO languages will have something similar. It means the object whose instance method is currently executing. It's called "this" in Java and C++, "self" in Objective C, and probably a few other terms in other OO languages. In general, if you have an instance variable named "x" in your class, you can interchangeably refer to it as "x" or "this.x", the latter form being handy if you happened to name a parameter or local variable the same name. "this" is also used (as in your example) to pass a reference to the current object to other methods.
Another concept is "super", referring to instance variables and methods in the super-class of the current class. You'd be well-advised to study enough Java to fully comprehend these concepts before you attempt to do Android programming. Otherwise you'll be stumbling around in the dark. On May 15, 5:33 am, tyliong <[email protected]> wrote: > Hi, > > I am a newbie developer and have done iphone coding. I just don't > understand how some code works as it is not explained in my book. > > Toast.makeText(this, "Please enter a valid > number",Toast.LENGTH_LONG).show() > > what is "this" in the brackets > makeText("this",...) -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
