While working on an app I found myself in an unexpected situation when a piece of code that had been working fine began to throw an OutOfBoundException. After a bit of debugging I found that the culprit was the length of an array passed to the AddRow method of a ListBox instance.
Author: Javier Menendez
Object Oriented Programming (OOP) puts in our hands the ability to create apps in a flexible and powerful way. Xojo embraces that philosophy in the Xojo language itself, allowing us to implement code in a flexible way for reuse, extension and maintainability that reduces the development cycles. One of these language tools is, in fact, common in other low level programming languages: Casting or type conversion. If you are interested in this (and you should be), continue reading and discover what it is, why you should be interested in it and how can you use it in your next Xojo app!
Comments closedI’ve heard it several times: how can I export to PDF from Xojo? Sure, there are lots of answers pointing to a bunch of resources, including excellent plug-ins from third parties. But can you accomplish the same thing using an already available API? Yes, there is a remote API for that! The requirement is that your Xojo app will need to have access to Internet … and, of course, you’ll need to do just a bit of coding.
Comments closedAdmit it – this is one of those questions that, sooner or later, arise to every Xojo newcomer: How can I add new UI controls to the Window at runtime? And if you are considering this too, then the good news is that the answer is more simple than you probably expect… sitting right there on the Inspector under the Attributes tab. Yes, this is all about the Control Set!
Comments closedIn programming, iterators are the mechanisms that allow us to walk all the members of a collection without needing to know in advance how many of them compose such a collection; and for that we can find in Xojo the commands For Each… Next. What are the main differences in comparison to the conventional For… Next?
The first difference is that with For Each… Next we can’t assume that we are iterating the members of the collection in order, as it is the case when using the variable of the conventional For… Next as the Index in order to access a known member of the collection. The second difference is that the iterator will be invalid when the iterated elements are modified, or when we modify the amount of elements in the collection during the iteration process.
By default in Xojo, there are a couple of collections that are iterable: the already mentioned Arrays and also Dictionaries and FolderItem.Children. Wouldn’t it be great to extend this feature so we can add this behaviour to our own classes making them more flexible? The key to making this happen is using the two Class Interfaces already included in Xojo: Iterator and Iterable.
Comments closedSome days ago (or long, long ago, depending when do you read these lines) I received an email from a developer that was porting code from his old VisualBasic domain to the native, multi-platform Xojo. He asked me how can to get the difference between two dates? I’m pretty sure that most of you will have the answer, but I told him he’ll need Xojo.Core.Date and Xojo.Core.DateInterval. If you want to know how easy it is or how to get the same result for all your code based on the old date class, then I invite you to continue reading…
Comments closedipify is a very useful web service (an API) that promises to always be available to attend requests, letting us know the public (or external) IP address we are using to connect to Internet. We can get this small piece of information as pure Text or in JSON or XML formats.
This post was updated in 2021 to using Xojo’s API 2.0.
Comments closedAmong other topics, Cryptography and data ciphering always fascinated me. Beyond their mathematical perspective, most of the time it is a matter of putting them in practice with developed solutions: dealing with data only visible between the transmitter and the receiver. As it happens, the Xojo framework makes it really easy to deal with ciphered data.
Comments closedThe ContainerControl is one of the most versatile control classes included in the Xojo framework both for Desktop and Web apps. In fact, it paves the way to complex UI controls creation with the same simplicity you are used to while designing your window layouts. Even better, once you create your complex UI controls using the ContainerControl, you will be able to add them to your Window layouts as if they were regular controls. Plus, you will enjoy the fruits of better OOP encapsulation and the fact that you can create and use the controls dynamically at run time. Want to see this in action? Follow this tutorial and video to create the basis of a multiplatform search field based on the ContainerControl class.
Comments closedThe Inspector Behavior is a feature that you were probably not aware of at first glance when using the Xojo IDE. It is tightly related to the Inspector Panel you are already using for adjusting all the control settings and other classes instances properties.
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