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
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
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
A recent feedback case made me think that there may be a real lack of information about attributes.
A lot of people believe that attributes are key value pairs that must have a valid identifier as the NAME and ALWAYS have a quoted string for a value.
This is incorrect.
Attribute name can be quoted strings – meaning you can, by using a quoted string for the name – have names that include spaces that would normally be invalid.… Read the rest
Currently when you call a method in Xojo the parameters are matched up starting from the first to the last from left to right. They are matched up based on their position in the argument list.
One thing some other languages support is “named parameters”.
What this allows is a certain degree of flexibility that doesn’t exist with positional parameters like Xojo uses.… Read the rest
For anyone not using version control perhaps the easiest way to share code between various projects is to use external items. However, not everything cam be made external. Modules that contain classes & other modules cant be shared via external items.
So how can you share these ?
On macOS the answer is … ALIASES !!!!!… Read the rest
Back when I wrote Code for Safety I gave one example of something that I’m sure we’ve all done from time to time. Saving the state of some flag and then returning and having possibly multiple places to reset the flag we saved.
There’s another thats is more common with the advent of HiDPI support for Windows; drawing in a listbox event like CellBackGroundPaint Saving the graphics state, disabling antialiasing, and then needing to restore that state.… Read the rest