Interesting question from a dev I’ve know for a long time.
If I have a property that’s an enum, how do I tell that it’s not been set?
And this is a good question.
Because an enum is, at its core, an integer when you declare one and run its always initialized to the default value for an integer – 0.… Read the rest
Every once in a while you run into some code that tries to present a fairly abstract API to some class / module. Maybe this is in your own code or in code you have received from some other source.
But as you work with it you find that the abstraction reveals internal implementation details that really should not be known outside the class.… Read the rest
Interfaces are one of those things in Xojo, and many other computing languages, that can really help you make your code more reusable and generic.
For instance, suppose you need a class that is a “List”. You could write a single class, called list, that you could add items to, remove items from, and generally manipulate in a “list like way”.… Read the rest
Kind of an oxymoron. A constant should be .. well .. constant.
However there are times you want that constant to be permanent, or constant, and unchangeable but it needs to be computed at compile time.
And it turns out that in Xojo you can do that IF you define a constant in code like :
Const foo = 123
Const bar = 345
Const foobar = foo + barIf you assigned these constants to variables so you could inspect them like
Dim iFoo As Integer = foo
Dim iBar As Integer = bar
Dim iFooBar As Integer = foobar
breakyou would see that iFoo, iBar and iFooBar have the values 123, 345, and 468 as expected.… Read the rest
… Read the restIn a great factory one of the huge power machines suddenly balked. In spite of exhortation, language, oil and general tinkering it refused to budge. Production slowed down and the management tore its hair.
At last an expert was called in. He carefully examined the machine for a few minutes, then called for a hammer. Briskly tapping here and there for about ten minutes, he announced that the machine was ready to move.
I read a really good article the other day from a writer who was having issues with their clients and trying to collect on invoices that were overdue.
Now, I haven’t had to do this sort of thing in a very long time, but it seemed to me that I have run into the same sort of pushback this author got about charging lates fees.… Read the rest
A few threads on the forums have commented that the URLConnection isnt quite as easy to use as many might expect. In particular there are comments about having to know what error codes a platform might return makes it harder to use than it should be.
Normally Xojo hides this level of detail from us.
I was thinking about this problem and have come up with something of a solution that makes it possible to both know the specific error code and yet still write code that is portable.… Read the rest
A lot of times people have common code that they want in EVERY application they start working on. And there are a number of ways people achieve this – copy & paste, svn externals, or a whole host of other means.
But there is a much simpler way to start off with all that common code.… Read the rest
App Battles ! Winner takes all. Last man standing and all that !
No – nothing quite so fun (although it can be a lot of fun)
This has to do with the App class at design time vs the App METHOD (yes it’s a method) at runtime.
The app class at design time can be renamed however you want.… Read the rest
When using the “factory” pattern you should only be able to get a valid instance from the factory and NO other way. Thats kind of the point of the pattern – to reduce the number of points at which instances can be created. Normally in Xojo you might have a module with a method that can create instances, and its the only one allowed to do this.… Read the rest