Xojo Programming Blog – Page 45 – Blog about the Xojo programming language and IDE

Control Sets and ContainerControl: A New Approach

Published March 8, 2019 by Javier Menendez

A Control Set is the feature to use when there are several instances in a Window’s layout and you need to command (or access them) from code, both for those available by default in the Framework and ones based on your own graphic classes. For example, this allows us to invoke a method in a concrete instance, based on its control index, or invoke the same method to all of them (iteration). All of this without knowing in advance, at runtime, how many of such instances are placed in the layout.

An inconvenience of this feature is that you can’t use it when the graphic controls are placed on a ContainerControl due to the way ContainerControls are implemented. The good news is that this problem has an easy solution! Read on to learn about it:

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The Klingon Translator App You Definitely Need

Published March 7, 2019 by Paul Lefebvre

I love the new Star Trek Discovery and there are a fair amount of Klingons in it, from time to time. It occurred to me that someone has probably built a web service to translate English to Klingon and if so, I needed to build a Xojo app to use it.

A quick Google search turned up an API by FunTranslations: https://funtranslations.com/api/klingon

It has simple usage where you send along the text in English and you get back a JSON result containing the text translated to Klingon. Here’s the result of my 15 minutes of effort to use this in a Xojo desktop app:

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Binary Magic with Signed Integers

Published February 27, 2019 by Norman Palardy

In binary the high bit (the one immediately following the &b in Xojo code) is the “sign bit”. When it’s set to 1, the value is interpreted as “negative” and when it’s set to 0, the value is “positive”. Meaning that bit is not used as part of the “number” itself.

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Avoiding Common Programming Pitfalls

Avoiding Common Programming Pitfalls

Published February 25, 2019 by Paul Lefebvre

Code doesn’t care whether you are new to programming or an old pro, a citizen developer or the head of engineering, some missteps can catch any of us. Read on to learn some of the most common programming pitfalls and how to avoid them.

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Working with XML

Published February 21, 2019 by Paul Lefebvre

XML can sometimes be a bit confusing, so here are some tips to help you work with XML files.

First, you need to make sure your XML is really XML.

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Me vs. Self

Published February 14, 2019 by Paul Lefebvre

When you add a control such as a PushButton to a Window (or a WebButton to a WebPage or an iOSButton to an iOSView), an instance of the control is created for you and added to the layout. Code that is in the event handlers of a control added in this way can refer to both its own properties and methods as well as the properties and methods of the window.

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How Code One-Liners Can Make Debugging Harder

Published February 12, 2019 by Norman Palardy

A lot of times you’d think that single lines of code, aka “one-liners”, like

if j >= 145 condition then dosomething()

if condition then return

might not have any downsides. I would argue that they do.

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Tip: SQLite in RAM … to improve speed!

Published February 11, 2019 by Javier Menendez

It’s very usual to use encrypted SQLite databases in our Xojo projects where we expect to get the maximum read speed from them. But the truth is that encrypting the data in these databases can introduce a penalty in our queries, both from read and writing/updating data to them. How can we improve this? One technique is the creation of a new in-memory based SQLite database, where we will be able to copy the table (or tables) we are interested in getting the maximum speed possible with. Continue reading to see how to do this.

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Recursion: Emptying a Folder

Published February 4, 2019 by Javier Menendez

Do you need code to delete the files and folders from the selected folder? In that case, there is a technique I propose to you and that is based on recursion. That is, the ability of a function to call itself repeatedly until the task is complete; in this case, the function will call itself every time it detects a new folder/directory inside the designated original folder/directory.

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Web: Create Sliding-Animated Menus

Published January 30, 2019 by Javier Menendez

Sometime ago a Xojo user asked if it is possible to use Xojo Web to create the kind of animated menus seen in several regular websites. After some investigation (and the invaluable help of Greg O’Lone), the answer is: yes, you can do that! If you are interested in seeing how to achieve this, continue reading!

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