I have an app with a window containing a box that contains maybe 100 checkboxes.
When I press a button I'd like to build a string of the titles of the selected checkboxes.
I know I need to iterate over all the checkboxes and get the titles but I can't figure out how to do that. Any pointers would be greatly appreciated. I know how to do it with bindings and tags but with 100 checkboxes that's just crazy!
Thanks!
I'd suggest you to use a stack view or a collection view. If you want to use simple checkboxes you have to keep pointers either in an array to iterate over or put them in a custom view as container where you iterate over its subviews.
This example will point you in a direction:
NSMutableArray *activeButtons = [NSMutableArray new];
for (NSView* subview in [self.container subviews])
if ([subview isMemberOfClass:[NSButton class]] && [(NSButton*)subview state] == 1)
[activeButtons addObject:[(NSButton*)subview title]];
NSString* text = [activeButtons componentsJoinedByString:#", "];
NSLog(#"Active: %#",text);
The isMemberOfClass method will ensure to only get buttons and not texts. you may additionaly check for the kind of button to ensure to only get checkboxes if you also have other buttons in the container. There are faster ways like enumeration but this is a better starting point imho.
Note: written on mobile... untested so excuse a possible typo (though double checked)
Related
Since some days I am trying to code an autocompletion for a NSTextField. The autocompletion should look that way, that when the user clicks on the NSTextfield a list should be displayed under the TextField which possibilities are available. After typing one letter or number the list should refresh with the possibilities.
The suggestions in this list should come from an NSMutableArrayor a NSMutableDictionary
This autocomplete / autosuggestion method should be for a MAC application.
Just adding to #AbcdEfg's answer, to make NSComboBox case-insensitive, you can subclass it and override it's [completedString:] method like this:
- (NSString *) completedString:(NSString *)string {
NSUInteger l = [string length];
if (!!l)
for (NSString *match in [self objectValues])
if ([[match commonPrefixWithString:string options:NSCaseInsensitiveSearch] length] == l)
return [match stringByReplacingCharactersInRange:NSMakeRange(0, l) withString:string];
return nil;
}
You can use NSComboBox for that matter. You also need to set its Autocompletes attribute in IB or [comboBox setCompletes:YES] in code.
Keep in mind that it is case-sensitive.
However if you need it to be done in the exact way that you described, you need to make the list by subclassing NSWindowController and NSTableView and change them to look like a list or menu to show under you NSTextField. Set the NSTextField's delegate and do the search and list update on text changes.
Avoid the NSMenu in this case as it will take away the focus from the text field while you are typing.
Apple addressed it in WWDC 2010 Session 145.
They explained about a text field with suggestions menu and how to get it to work. They also provide the sample codes in their website.
You can find the sample code here.
I want to show in a label the current number of elements in an NSArray called pages. Following other guides I did the following:
Created an NSArrayController in IB (called pagesController) and bounded it to the NSArray pages
Bounded the value property of the label to the NSArrayController with Controller Key = arrangedObjects and Model Key Path = #count
The problem is that when the program is running the label always shows "0". To check if the things are working correctly I tried to log a message when the user clicks on another button (the button basically inserts a new element in the pages array): NSLog(#"count = %d", [self.pagesController valueForKeyPath:#"arrangedObjects.#count"]); in this case the output is correct, i.e. the current number of elements in the array printed is correct.
Where am I mistaking?
You many not be using KVC correctly. Your array controller will only be notified with the pages property is redefined, not when objects are added to the array. Try wrapping your code with the appropriate change notifications:
[self willChangeValueForKey:#"pages"];
[pages addObject:someObject];
[self didChangeValueFOrKey:#"pages"];
Suppose I have two buttons that are ivar outlets. One is called "Blue" and the other "Red." Now, I have an NSString with the value of "Red." I want to set the button identified by the NSString to a selected state, without using if.
I do not want to do this:
NSString *button=#"Red";
if ([button isEqualtoString:#"Blue")
self.blue.selected=YES; //self.blue and self.red are UIButtons
else
self.red.selected=YES;
This is fine if you have two buttons, but I have quite a lot more than that, and it would be quite inelegant and cumbersome to do this for like 30 buttons.
I'd much rather find a way to directly link the name of a UIButton ivar to the value of an NSString.
Put the string lower case and
you can use KVC for that :
[self setValue:[NSNumber numberWithBool:YES]
forKeyPath:[NSString stringWithFormat:#"%#.selected", button]];
You can put the buttons in a dictionary :
[NSDictionaryName addObject: UIButtonName forKey: #"blue"];
or something like that :
[NSDictionaryName objectForKey:#"blue"].selected = YES;
I have anNSTableView showing the contents of a directory. I watch for FSEvents, and each time I get an event I reload my table view.
Unfortunately, the current selection then disappears. Is there a way to avoid that?
Well, you can save selection before calling reloadData and restore it after that.
NSInteger row = [self.tableView selectedRow];
[self.tableView reloadData];
[self.tableView selectRowIndexes:[NSIndexSet indexSetWithIndex:row] byExtendingSelection:NO];
This worked for me in some cases. But if you insert some items BEFORE the selected row, you should andjust your row variable by adding count of added items to it.
Swift 4.2
Create an extension and add a method which preserves selection.
extension NSTableView {
func reloadDataKeepingSelection() {
let selectedRowIndexes = self.selectedRowIndexes
self.reloadData()
self.selectRowIndexes(selectedRowIndexes, byExtendingSelection: false)
}
}
Do this in case you use the traditional way of populating table views (not NSArrayController).
It depends on how you populate your NSTableView.
If you have the table view bound to an NSArrayController, which in turn contain the items that your table view is displaying, then the NSArrayController has an option to preserve the selection. You can select it (or not) from within Interface Builder as a property on the NSArrayController. Or you can use the setPreservesSelection method in code.
However, if you completely replace the array of items that the NSArrayController manages each time you get your FSEvents, then maybe the preservation of selection cannot work. Unfortunately the Apple docs on this property of NSArrayController are a bit vague as to when it can and cannot preserve the selection.
If you are not using an NSArrayController, but maybe using a dataSource to populate the table view, then I think you'll have to manage the selection yourself.
In the case of using Data Source, Apple Documentation in the header file on reloadData() is that
The selected rows are not maintained.
To get around, you can use reloadDataForRowIndexes(rowIndexes: NSIndexSet, columnIndexes: NSIndexSet). As mentioned in the same header file
For cells that are visible, appropriate dataSource and delegate methods will be called and the cells will be redrawn.
Thus the data will be reloaded, and the selection is kept as well.
A variant on #silvansky's answer.
This one has no need to keep track of count of items inserted/deleted. And it maintains multiple selection.
The idea is to...
1. create an array of selected objects/nodes from the current selection.
2. refresh the table using reloadData
3. for each object obtained in step 1, find/record it's new index
4. tell the table view/outline view to select the updated index set
- (void)refresh {
// initialize some variables
NSIndexSet *selectedIndexes = [self.outlineView selectedRowIndexes];
NSMutableArray *selectedNodes = [NSMutableArray array];
NSMutableIndexSet *updatedSelectedIndex = [NSMutableIndexSet indexSet];
// 1. enumerate all selected indexes and record the nodes/objects
[selectedIndexes enumerateIndexesUsingBlock:^(NSUInteger idx, BOOL *stop) {
[selectedNodes addObject:[self.outlineView itemAtRow:idx]];
}];
// 2. refresh the table which may add new objects/nodes
[self.outlineView reloadData];
// 3. for each node in step 1, find the new indexes
for (id selectedNode in selectedNodes) {
[updatedSelectedIndex addIndex:[self.outlineView rowForItem:selectedNode]];
}
// 4. tell the outline view to select the updated index set
[self.outlineView selectRowIndexes:updatedSelectedIndex byExtendingSelection:NO];
}
I am working on an app that is not core data based - the data feed is a series of web services.
Two arrays are created from the data feed. The first holds season data, each array object being an NSDictionary. Two of the NSDictionary entries hold the data to be displayed in the popup ('seasonName') and an id ('seasonID') that acts as a pointer (in an external table) by matches defined for that season.
The second array is also a collection of NSDictionaries. Two of the entries hold the data to be displayed in the popup ('matchDescription') and the id ('matchSeasonId') that points to the seasonId defined in the NSDictionaries in first array.
I have two NSPopUps. I want the first to display the season names and the second to display the matches defined for that season, depending on the selection in the first.
I'm new at bindings, so excuse me if I've missed something obvious.
I've tried using ArrayControllers as follows:
SeasonsArrayController:
content bound to appDelegate seasonsPopUpArrayData.
seasonsPopup:
content bound to SeasonsArrayController.arrangedObjects; content value bound to SeasonsArrayController.arrangedObjects.seasonName
I see the season names fine.
I can obviously follow a similar route to see the matches, but I then see them all, instead of restricting the list to the matches for the season highlighted.
All the tutorials I can find seem to revolve around core data and utilise the relationships defined therein. I don't have that luxury here.
Any help very gratefully received.
This is not an answer - more an extension of the previous problem.
I created MatchesArrayController and subclassed it from NSArrayController to allow some customisation.
Following the example in 'Filtering Using a Custom Array Controller' from 'Cocoa Bindings Topics', I followed the same idea as above:
MatchessArrayController: content bound to appDelegate matchesPopUpArrayData.
matchesPopup: content bound to MatchesArrayController.arrangedObjects; content value bound to MatchesArrayController.arrangedObjects.matchDescription.
I've derived the selected item from seasonPopUp:sender and used this to identify the seasonId.
The idea is to change the arrangedObjects in MatchesArrayController by defining the following in;
- (NSArray *)arrangeObjects:(NSArray *)objects
{
if (searchString == nil) {
return [super arrangeObjects:objects];
}
NSMutableArray *filteredObjects = [NSMutableArray arrayWithCapacity:[objects count]];
NSEnumerator *objectsEnumerator = [objects objectEnumerator];
id item;
while (item = [objectsEnumerator nextObject]) {
if ([[[item valueForKeyPath:#"matchSeasonId"] stringValue] rangeOfString:searchString options:NSAnchoredSearch].location != NSNotFound) {
[filteredObjects addObject:item];
}
}
return [super arrangeObjects:filteredObjects];
}
- (void)searchWithString:(NSString *)theSearchString {
[self setSearchString:theSearchString];
[self rearrangeObjects];
}
- (void)setSearchString:(NSString *)aString
{
[aString retain];
[searchString release];
searchString=aString;
}
I've used NSLog to check that things are happening the way they are supposed to and all seems ok.
However, it still doesn't do what I want.
[self rearrangeObjects]; is supposed to invoke the arrangeObjects method but doesn't. I have to call it explicity
(i.e.[matchesArrayController arrangeObjects:matchesPopUpArrayData]; )
Even then, although filteredObjects gets changed the way it is supposed to, the drop down list does not get updated the way I want it to.