Electronics overload? Declutter your home and office with Xojo! Learn how simple it is to build a Xojo Server app to replace that old clock radio. Wayne…
Category: Web Development
Posts related to web development.
Using databases with web apps is not much different than using them with desktop apps, but there are a few things to keep in mind. The most important thing to note is that a web app allows multiple users. This means you’ll want your database connection to be unique for each user that connects to the web app, rather than global to the app itself (as is common in desktop apps). The simplest way to ensure this is to create the connection to your database in the WebSession.Open event handler, saving a reference to the connection as a property that you add to WebSession.
Xojo is similar to VB, Java and C#
The Xojo programming language is fully object-oriented and uses an object model that is quite similar to VB, Java and C#. If you are used those languages at all, you’ll be right at home with Xojo.
Available since 1998, Xojo was one of the first languages to use Automatic Reference Counting (ARC), something that other languages such as Swift and Objective-C now use. Xojo is type-safe and fully object-oriented making it easy to learn and use, but it also has advanced features such as namespaces, extension methods, exception handling, introspection, delegates and more.
The most direct way to support HiDPI* for custom controls is to draw into the Graphics object passed into the Paint event. That graphics object is already configured with the appropriate scale factor and double buffering- the entire control will be handled correctly by the framework if the DoubleBuffer property is set.
*As with other posts, we’ll use “HiDPI” to refer to both HiDPI on Windows and Retina on OS X.
“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…
Most of us build applications 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?
By default the built-in Web Browser that is used on Windows to show web pages uses the Internet Explorer 7 rendering engine. Which means the Xojo HTMLViewer and the ActiveX WebBrowser controls also use this older rendering engine.