Xojo Programming Blog – Page 79 – Blog about the Xojo programming language and IDE

Xojo Retina/HiDPI: The journey of a thousand pixels…

Published April 5, 2016 by Greg O'Lone

“Retina” is the name for high resolution screens on Mac and iOS devices while “HiDPI” is the Windows equivalent. For simplicity, I’ll use HiDPI (which really is the universal technical term) for the rest of this blog post. Now that we have HiDPI support in Xojo, if you app doesn’t use any pictures, you can simply open your project, click on Shared under Build Settings and turn on the “Supports Retina/HiDPI” option. That’s all you need to do to have a HiDPI version of your app!

Having said that, if you are creating or using pictures in your project, there may be a few adjustments you’ll need to make to your code. A little over a year ago the process of making sure we had all of the necessary graphics together to build a Retina/HiDPI IDE was added to my to-do list. While 95% of the icons created for the Xojo IDE in 2013 already existed, most of the graphics that made up the IDE itself did not, and the IDE itself needed a bit of an overhaul to get it ready for the big change, both in graphics and in code…

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An Introspection Gotcha

Published April 4, 2016 by Norman Palardy

Introspection is a very handy and useful part of the Xojo language.

You can use Introspection to examine many of the objects that are in memory at runtime. You can access the properties in those objects, call methods on those objects and even create new instances- with some caveats of course.

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Headless Pi: Using Xojo and Raspberry Pi Without a Display

Published March 30, 2016 by Paul Lefebvre

You don’t need to hook up your Pi to a physical display, keyboard and mouse. You can set up VNC on the Pi so you can remotely connect to it.

My Raspberry Pi 2 sits on my desk next to one of my speakers. It’s not hooked up to any display. I use a combination of SSH, SFTP and VNC when I need to work with it.

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Houston, Here We Come: Things to Do, Eat and Visit in Space City

Published March 22, 2016 by Alyssa Foley

Visitors to Houston will find the city is served by 2 large, international airports (IAH & HOU), the restaurant scene is diverse and extensive, the city’s museums range from the acclaimed Children’s Museum to the beautiful Rothko Chapel, and the attractions of the surrounding area.

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Let’s Talk Office Ergonomics

Published March 16, 2016 by Paul Lefebvre

If you work at a desk all day, you should be thinking about your ergonomics.

Being comfortable while you work is important. It enables you to concentrate better, but more critically, it prevents you from injuring yourself. From Musculoskeletal to vision and hearing problems, yes, it is quite possible to injure yourself while working at a desk!

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Reordering SQLite Table Columns

Published March 14, 2016 by Paul Lefebvre

I recently had someone ask me how to reorder the columns in a SQLite table. As you may be aware, the SQLite ALTER table does not have a lot of functionality compared to other databases and it certainly doesn’t have a way to do this.

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Easily Sorting Arrays of Classes

Published March 9, 2016 by Paul Lefebvre

Sometimes you’re going to need a data structure that is an array of classes and you’re going to want to sort them. The standard array Sort method can only sort simple types (Text, Integer, etc), so what do you do?

The traditional technique has been to use SortWith. You create a separate array of a simple type, populate it and then sort the temporary array using SortWith to sort the class array.

But there is an even slicker way to sort that was added in 2015 Release 3. You can now create your own custom comparison method and use that to sort the class. This custom method returns 0 if the values to compare are equal, a positive if the first value is greater than the second, and a negative value if the first value is less than the second.

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Raspberry Pi 3 Announced!

Published March 8, 2016 by Paul Lefebvre

On Monday February 29th, the Raspberry Pi Foundation announced the new Raspberry Pi 3. This updated Pi has some significant improvements over the Pi 2, including:

A 1.2GHz 64-bit quad-core ARM Cortex-A53 CPU (~10x the performance of Raspberry Pi 1)
Integrated 802.11n wireless LAN and Bluetooth 4.1
Complete compatibility with Raspberry Pi 1 and 2

That last bullet point is notable because it means that Xojo is also fully compatible with the new Raspberry Pi 3!

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Sorry, You’ve Run Out of Memory

Published March 4, 2016 by Geoff Perlman

Most of us build apps without thinking too much about how much memory the app will need. Sure sometimes you end up creating an app that is a real memory buster but that’s unusual. With virtual memory, gone are the days when your app would just run out of memory and crash, or are they?

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How to Recursively Delete a Folder

Published March 2, 2016 by William Yu

While Xojo doesn’t currently provide a direct way of recursively deleting a folder, there are various options that will allow you to do this:

1. Recursively iterate through all the folders, deleting each one. You can read about that at our Developer Site, this is the best cross-platform way.
2. Use the Shell to recursively delete a folder (i.e. “del /s” on Windows, or “rm -rf” on OS X and Linux)

Windows specific ways:
3. SHFileOperation (an older API)
4. IFileOperation (the more modern API that Windows recommends over option #3)

I’ve decided to look at option #4, since this allows more customized options, like the ability to show a progress dialog. However, it is also the slightly more complicated option since it deals with COM & Delegates. The example illustrates this:

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