Some years ago, Xojo introduced the ability to use Computed Properties, something that is present in other programming languages too and is based on the use of dedicated methods to assign and retrieve the property value itself. So, in other programming languages, the first of these dedicated methods (or functions), the Setter, is the one invoked every time we want to modify the value of the associated property, while the Getter method is the one used from our code to retrieve the associated value. The Object-Oriented Programming (OOP) concept found behind this feature is Method Overloading. Nevertheless, let’s make clear that Xojo Computed Properties are not methods. They aren’t! But they make our life as developers much easier compared with regular Properties.
Comments closedAuthor: Javier Menendez
Have you ever wondered how the magic behind the “mailto://” or other similar Uniform Resource Identifiers (URI) work? Whether from the web browser URL field or from Xojo via the ShowURL function, when URIs are executed the registered app opens showing the passed parameters (for example, in the Mail app for the ‘To’, ‘Subject’ and ‘Body’ fields).
Implementing this kind of behavior in your OS X apps is not rocket science! Follow these simple steps in order to register a custom URI from your app.
Comments closedObject Oriented Programming with Xojo, and in this case Event Oriented Programming as well, is simply wonderful. You create objects (Instances) from the defined classes that act as templates and just let them roll. From there, the interactions made by the user are those that determine how objects interact with each other via sending messages to each other (method calls), the access to properties and also the execution of events.
However, sometimes the combination can simply reach unstable situations by the very nature of our applications and here is where failures can arise in memory management. Fortunately, we can keep this under control with the help of the WeakRef class.
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