Javier Menendez – Page 14 – Xojo Programming Blog

Prepare Your Classes to Work in Simulated or Real Modes

Published June 1, 2018 by Javier Menendez

In many of our development projects, if not all, we are confronted with situations when we need to test our classes before the final deployment of a project. I’m not talking about Unit Testing here, though I highly recommend the excellent session on that topic from XDC 2018.

For example, it would not be desirable to send hundreds of emails to all the entries in a database simply to test one of the workflow steps or to verify that emails are being delivered as expected. It would be a lot simpler, and less disruptive to those using your app, to test using a few email addresses that are under your control.

So let’s establish a mechanism that allows us tell our apps when to run in a “simulated” mode vs. a “real” mode for all or some of the components that we need to test along the development cycle.

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Create Your Own ImageWell Based on Canvas

Published May 7, 2018 by Javier Menendez

Whether you are using Xojo to create your very first application or if you are coming from other languages, like C# or VisualBasic, customized UI controls are probably one of those things you have in your to-do list. For multiplatform Desktop apps, you will find that the Canvas class offers everything you need. In order to show you how easy it can be, follow this tutorial to recreate the ImageWell UI class control, provided by default in the Xojo framework. Our customized ImageWell will be able to proportionally display any JPEG file dropped by the user on the control, centering it on the available surface.

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Beware the Length When Dealing with Arrays

Published May 4, 2018 by Javier Menendez

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.

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Casting, get ready and keep the Type!

Published March 21, 2018 by 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!

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PDF File Generation? There is an API for that!

Published February 6, 2018 by Javier Menendez

I’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.

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How to Add User Interface Controls at Runtime

Published January 26, 2018 by Javier Menendez

Admit 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!

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Make Your Own Classes Iterables

Published December 13, 2017 by Javier Menendez

In 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.

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Dates…What’s the difference?

Published October 31, 2017 by Javier Menendez

Some 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…

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ipify for Xojo

Published September 26, 2017 by Javier Menendez

ipify 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.

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RSA: Private/Public keys between Xojo and PHP

Published June 6, 2017 by Javier Menendez

Among 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.

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Author: Javier Menendez