Making a constructor sometimes illegal to call

Suppose you write a control subclass that you want people to be able to add to a window layout OR be able to create on the fly. But you want to make sure that when an instance is constructed in code it MUST have a parameterized constructor. However, in order to put an instance on a layout by drag and drop it has to have a no parameter constructor.… Read the rest

Sampling with a delay

MacOS terminal is a useful tool to know for a few really handy things.

One is getting a sample of a process after some delay so you can start doing whatever it is you want to sample.

Trying to do this in Activity monitor is not possible

But at the command line you can delay the start of the sample so you have a chance to set up the sampling and then switch back to Xojo to do the task you want sampled.… Read the rest

Why shadowing should be avoided

We’ll create a sample project to demonstrate why its a bad thing to do.

Start a new desktop project.

Add a new Class that is a subclass of ”CancelButton” by dragging a CancelButton from the library to the Navigator.

Name this new class “myPushButton”

Add a property  to it – enabled as boolean

Make sure the property is public

Now on Window1 add an instance of this new button subclass.… Read the rest

Simple but really useful alternate menus

macOS supports the notion of Alternate menus. One that even once you have opened the menu you can toggle between their textual description and short cut by pressing the Option Key or another modifier like Shift or Control.

And you can even set up several so pressing Shift is one, Shift + Ctrl is another, and Option is yet another.… Read the rest

My departure

Originally published on my old blog March 12, 2019

After Joe Ranieri quit* & moved to a new job I think everyone felt stressed. I know I did. It felt like so much more was expected of an ever smaller group of developers.

By Dec of that year I’d had enough of the forums and some of the general dumping on Xojo as a product.… Read the rest

An extensible class factory

Some times you want to make a nice generic class that a user can extend via subclassing.

However, one issue arises with this.

How can a factory method in the super class create instances of the subclasses ? This is especially troublesome if the classes you have are encrypted so you cant change the source or in a plugin.… Read the rest

Code for safety

Lots of time you see code like

static flag as boolean 
if flag then return

flag = true

// rest of method

flag = false

In a simple method/event with only a handful of lines there’s probably nothing wrong with this

But what do you do when the method spans into hundreds or thousands of lines ?… Read the rest