Objective-C: Creating a file purely for holding variables

Question

I would like to add a file to my project, who's sole purpose would be to hold an array. I would then #import this file wherever I need to add/get from the array.

My problem is that when I create a new file (I'm using Xcode 4), I'm not sure what type of template to choose, and then what subclass to choose.

My reason for doing all of this is because I have a SplitView-Based app, and one of the views has a textfield, where I am trying to output data. My problem is that whenever I switch to a different view and then switch back, only the most recent entry is there. I am not 100% why that is but I suspect it is because when I switch to a different view, the current view is forgotten about, along with the variables in it.

Answer 1

This is not a good way to do it. There are many ways to do what you want: prepareForSegue: if you are using storyboards, delegation, instantiating your viewcontroller in code and setting a property in the header-file..those are just a few ways.

The way you are proposing is a slippery slope to bad Objective-C code and is only going to cause you more headaches in the future. Take the time to learn to do it right.

Check out this to get you thinking in the right direction.

Answer 2

How you save your data doesn't appear to be your problem. Take a look at the MVC design pattern and how view controllers implement it. They often rely on a dataSource protocol, which links the data from a "Model" to your "View" in a logical way to achieve your intended purpose.

The view controller should then be able to assign a delegate (usually itself (self) to keep the view populated with the correct data, whether the view gets unloaded or not.

If your view controller doesn't refer to a data source or a corresponding protocol, it would still be worth your time to see how you might take advantage of that design pattern. It will pay off in the long run to know this.

Answer 3

Instead of saving variables to a text file, you should consider using NSUserdefaults instead.

But I don't think that's the real solution to your problem, just wanted you know that there are other ways than saving stuff to a text file.