I had my iPhone app working, developed with Storyboard. I decided to take all of the methods that belonged in a SQLite method and move them to a new SQLite class (.h and .m).
Now I have errors that I can't seem to get rid of. The basic problem is the textfields on the "scene" are now unreachable from the SQLite class (they are in another class, where they belong). The properties are defined in EDVController.m... I am trying to reach them from SQLite.m.
I have read the docs, but can't find anything that fits my problem.
How do I do this?
I give full credit to Jeremy Roman... I would up using NSMutableDictionary to pass the parameters, and it works like a champ! Thank you Jeremy and Jia Yow.
Related
I am learning Objective-C Cocoa programming for OS X, and object-based programming in general, so I am a big novice here, so my question is a bit general and my guess is the answer to this is simply "experience"; however, I am curious if there is some route of knowledge to understanding what methods in various classes are best or perhaps required for getting tasks done.
For example, in a programming guide I am instructed to create a document-based program, and the document class contains an array to store data, with the following method bound to a button to create a new entry in the array:
- (IBAction)insertItem:(id)sender {
if (!theItems) {
theItems = [NSMutableArray array];
}
[theItems addObject:#"Double-click to edit."];
[theTableView reloadData];
[self updateChangeCount:NSChangeDone];
}
The array is "theItems" and its data is being presented in a TableView object. I understand that the steps here add a new string to the array and then refresh the table to display it, followed by setting the document to be set to an unsaved state.
What I am not getting is how one would know these specific steps and methods are required. Intuitively it seems one would just add items to the array, and that would be all that's required to have the new values simply show up in the table view for which the array is the data source, so how would one know that the tableView would need to be refreshed with the "reloadData" call? I can see someone (myself) figuring it out by trial and error, but is there some quick resource or guide (ie, some quick flow-chart) either in XCode or elsewhere that indicates for a table view that this would have to be a required action to display the new entry?
If I look at Apple's NSTableView class reference, it claims in the overview that you "modify the values in the data source and allow the changes to be reflected in the table view" which suggest the view is updated automatically, so the requirement to call "reloadData" on the view seems a little obscure.
Look for the guides. In the online class reference for NSTableView, there's a section at the top called "Companion Guides". For NSTableView, it lists the Table View Programming Guide for Mac. (In the prerelease 10.10 docs, the guides are listed under Related Documentation in the left-hand sidebar.)
I could have sworn this same information was available in Xcode's Documentation window, albeit somewhat hidden behind a "More related items" pseudo-link, but when I check right now there's no link to the guide anywhere in the NSTableView class reference. Which is a terrible oversight.
You can also browse or search the Guides section of the developer library.
Familiarity, studying the documentation and possibly reading some good books is the answer. For example, in the docs you quoted (emphasis mine)
you should modify the values in the data source and allow the changes to be reflected in the table view
You should do both these things. If you want it to happen "automatically", look into bindings, which uses several other Cocoa features you won't understand at this point either to do the table data source stuff for you. I'd recommend understanding what is happening manually before handing over control to bindings, so you have some chance of understanding when things go wrong.
As well as looking at the table view documentation, you also need to study the cell, delegate and datasource references. All of those objects work together to give you the functioning table view.
I defined a class called "FilterCriteria" which has a bunch of function .m files (getAMask, getBMask, etc.) associated with it. When I create the FilterCriteria object and call the functions using it, I don't have any problems. However, recently I added another function (which, on a side note, is almost identical to another function that still works), and Matlab returns the error, "No appropriate method, property, or field getHMask for class FilterCriteria."
I've searched online for this problem, but I can't find anything. The file getHMask.m is definitely in the correct folder, so I don't understand why Matlab seems to have such a problem finding it.
Here's getHMask.m's header:
function mask = getHMask(object, quadrant, channel)
Any help would be greatly appreciated. Thanks in advance.
1) A mistake I make sometimes is not saving the file with the correct name. Make sure capital letters are in the right places etc!
2) Another layer of error checking here... You can call methods('object here') (see here) and make sure it lists the method (function) that you are trying to add to it. If it doesn't show up here you should check into the implementation of the method and make sure it's correctly being added to the class you're using for your object.
I had the same problem that's kind of suggested by Ben's bullet #2 and it was driving me crazy. Turns out MatLab wasn't loading the latest version of my class's m-file. I vaguely remembered it gave me a warning earlier about that, because there were old instances of the class in the workspace and to keep from invalidating them it said it wouldn't update the class until I cleared the workspace...
So if that's the problem, restarting MatLab will work, or you can just enter >> clear
I'm struggling to use Chromium Tabs in Cocoa and I really seem to be missing something.
I've subclassed CTBrowserWindowController (ppEditor), CTBrowser (ppDocumentBrowser), CTTabContents (ppDocument) and CTTabContentsController (ppDocumentController)
Editor creates new Documents by : [self addTabContents:(ppDocument*)doc]; (and I've also tried first adding a Document Controller for the specific document first, but this doesn't work either)
I'm connecting my outlets from TabContents.xib (either to File Owner : ppDocumentController or to an instance of ppDocument I'm adding to the XIB), but it doesn't work and the outlet instances show up (intermittently) as NULL pointers.
So, what could be going wrong?
NOTE :
When connecting actions (either to the ppDocument class, or the ppDocumentController), these - weirdly so - do work....
There is some cross-referencing between classes (e.g. there is a pointer to ppDocument from ppDocumentController, as well as one from ppDocument to ppDocumentController)
Problem solved.
Although, I have no idea how - I basically did the whole thing from scratch and ooops, it worked (I must have missed something in the first place...)
How I can create a code in XCode 4.2.1 what will create NSTableView and add just couple of items to it?
All what I wanted to do is:
1) Window where is NSTableView
2) I have an array of strings in NSArray which I like to show in that NSTableView
3) All of this should be done in code. So I don't want to learn how to add this action happen when you press button (I know already how to do actions when user click buttons etc), I just want that application launch -> draws the table where is those items from my array. That's it, nothing more.
And yeah I have understood that I do not add items to NSTableView directly. That is not the point in this question. I just mean that I want to show couple of items in that table but I have no and kind of clue WHERE I should add my data from my array.
I have tried to google for example pages for hours (just too many and have not find help) but I will always be stucked in the part when
a) I must do something in the Interface Builder and the images of the interface builder are from version 2.x or 3.x and I have 4.2.1 and it is totally different (new to XCode...). Surely I have drawn my TableView element to UI but I mean delegations etc. Are those necessary at all? Can those be made from source code?
b) Code just does not work anymore because language (Cocoa or Objective-C, I don't know) has changed and I don't know how and what I have to do to make it work on newest version of XCode.
c) There is too much different ways told: "use binding", "you must create new class what is NSTableViewDataSource" etc. I have no any kind of clue what is preferred way, is another way optional or it is "you should use this because another is going deprecated soon" or something.
So please, can somebody give help in step-by-step what I exactly have to do? Should I create some bindings? If so, how and where? Do I have to create DataSource component myself? Are those ways valid any more? If I have to, how I can create it? Create a new class and implement it as a NSTableViewDataSource and then use it? Is that way valid any more and if it is, can sombody show code what is as simple as possible?
I have also checked Apple Documentation page many many times, checked those example codes but there is just too much totally unrelated stuff that I just don't understand at this point so they are totally useless (I mean, I don't know what is required for this task, what are not etc.
I would be very happy if somebody can help short tutorial step-by-step what to do. I mean "step-by-step" like:
1) Create new project
2) Draw NSTableView in project
3) Create new class with this name
4) Write this code: blah blah blah
5) Create another class with this name
6) Write this code
7) Run and see those items from array in NSTableView using (bindings/datasource/whatever is preferred).
Thanks :)
Your tableview needs a datasource. Your datasource is a custom class, it implements the "NSTableViewDataSource" protocol. This protocol contains a few methods that you can use to tell the tableview what data you got.
this includes the objectValue ( the value of the NSCell that is displaying your data on the specified row, and a method that returns the amount of rows the tableview has ( the amount of items in your array ).
Here a tutorial I found by googling:
CocoaDev.com NSTableView tutorial
You can also implement the NSTableViewDelegate protocol which allows some greater control. Like what rows you can select, or some extra configuring of a custom tableview cell.
I must say that back in the day when I started developing desktop applications ( only had experience with web technologies ) that this design pattern confused me as well. Hope you will get your mind round it soon.
I have a class (that inherits from a base class) and also has image assets for some UI elements. I would like to be able to wrap this up images and all, into a single file that can easily be added to future projects by myself and other members of the dev team. Is there a way to do this? Adding a documentation file, a la Apple's own that responds to cmd click within XCode would be the icing on the cake.
Cheers
Dave
You create a static library... see the following Tutorial