Filtering a NSTreeController with NSSearchField ? - nspredicate

This question seemed to be asked before but was never answered. So is it possible to filter a NSTreeController with NSSearchField? If so, then how?
Thanks!

If your question is "can it be done in IB, just like NSArrayController using the bindings inspector?", then the answer is "No". Although IB suggests that the binding is possible (one can make the actual binding) it will generate an exception as NSTreeController has no predicate.
I suppose it should be possible by implementing subclasses although it would be a bit of a challenge as the filtering process will have impact on the tree structure of your data.
EDIT: It can actually be done with a bit of code. Presuming you have view controller set as the delegate for your NSSearchField, you implement the following method for your delegate:
- (void)controlTextDidEndEditing: (NSNotification *)aNotification {
NSPredicate *aPredicate = nil;
if ([[[self mySearchField] stringValue] isEqualToString:#""]) {
aPredicate = [NSPredicate predicateWithFormat: #"parent == nil"];
} else {
aPredicate = [NSPredicate predicateWithFormat:#"name contains[c] %#", [[self mySearchField] stringValue]];
}
[[self myTreeController] setFetchPredicate: aPredicate];
[[self myOutlineView] reloadData];
}
The above filters the tree based on a name attribute. Note that filtering a tree view can have strange effects on the tree structure. Also note that when an empty string is presented, the method creates the default predicate which filter the top level entries from the datasource and reinstates the tree view.

Related

NSTreeController - Retrieving selected node

I added Book object in bookController (NSCreeController). Now i want to get stored Book object when i select the row.
- (IBAction)addClicked:(id)sender {
NSTimeInterval timeStamp = [[NSDate date] timeIntervalSince1970];
// NSTimeInterval is defined as double
NSUInteger indexArr[] = {0,0};
Book *obj = [[Book alloc] init];
NSString *dateString = [NSDateFormatter localizedStringFromDate:[NSDate date] dateStyle:NSDateFormatterNoStyle timeStyle:NSDateFormatterLongStyle];
obj.title = [NSString stringWithFormat:#"New %#",dateString];
obj.filename = [NSString stringWithFormat:#"%d",arc4random()%100000];
[self.booksController insertObject:obj atArrangedObjectIndexPath:[NSIndexPath indexPathWithIndexes:indexArr length:2]];
}
I concede there perhaps could be a better solution--
I am unfamiliar with how NSTreeController works, but I looked a the class reference and noticed that it has a content property, similar to an NSArrayController (Which I am familiar with grabbing specific objects from).
I believe that if the content property is actually of type of some kind of tree data structure, my answer here probably won't work. The class reference says this about content:
The value of this property can be an array of objects, or a
single root object. The default value is nil. This property is
observable using key-value observing.
So this is what I historically have done with the expected results:
NSString *predicateString = [NSString stringWithFormat:NEVER_TRANSLATE(#"(filename == %#) AND (title == %#)"), #"FILENAME_ARGUMENT_HERE", #"TITLE_ARGUMENT_HERE"];
NSArray *matchingObjects = [[self content] filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:predicateString]];
Then simply calling -objectAtIndex: will grab you your object. Note that the NSArray will be empty if the object doesn't exist, and if you have duplicate objects, there will be multiple objects in the array.
I also searched for an answer to your question, and found this SO thread:
Given model object, how to find index path in NSTreeController?
It looks pretty promising if my solution doesn't work, the author just steps through the tree and does an isEqual comparison.
If you could (if it's not too much trouble), leave a comment here to let me know what works for you, I'm actually curious :)

Sorting NSTableView

I have two coloumn in NSTableView as Name and Salary with 5-10 values. I want to sort these coloumn after click on header of both the column. There is lots of data present in Internet but I am not able to use these. Please help me to do this in cocoa.
Thanks in advance and appreciate any help.
Each table column has a method setSortDescriptorPrototype
Sort descriptors are ways of telling the array how to sort itself (ascending, descending, ignoring case etc.)
Iterate over each of the columns you want as sortable and call this method on each of those columns, and pass the required sort descriptor (In my case I'll be using the column identifier)
for (NSTableColumn *tableColumn in tableView.tableColumns ) {
NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:tableColumn.identifier ascending:YES selector:#selector(compare:)];
[tableColumn setSortDescriptorPrototype:sortDescriptor];
}
After writing this piece of initialization code, NSTableViewDataSource has a method - (void)tableView:(NSTableView *)aTableView sortDescriptorsDidChange:(NSArray *)oldDescriptors that notifies you whenever a sort descriptor is changed, implement this method in the data source and send a message to the data array to sort itself
- (void)tableView:(NSTableView *)aTableView sortDescriptorsDidChange:(NSArray *)oldDescriptors
{
self.data = [self.data sortedArrayUsingDescriptors:sortDescriptors];
[aTableView reloadData];
}
This method will get fired each time a column header is clicked, and NSTableColumn shows a nice little triangle showing the sorting order.
I stumbled upon this question while looking for the easiest way of implementing something similar. Although the original question is old, I hope someone finds my answer useful! Please note that I am using Xcode 5.1.1
Ok so to do this you need to:
select the actual column you want to sort in your table.
In your Attributes Inspector you need to fill in two fields: Sort Key, and Selector.
In the Sort Key field, you need to enter the value of your Identifier. The value of your Identifier is located in your Identity Inspector.
In the Selector field you need to enter a suitable selector method based on the object type in the column. The default method is; compare:
Based on the Table View Programming Guide for Mac. The compare: method works with NSString, NSDate, and NSNumber objects. If your table column contains only strings, you may want to consider using the caseInsensitiveCompare: method if case sensitivity is unimportant. However, consider replacing these method signatures with the localizedCompare: or localizedCaseInsensitiveCompare: methods to take into the account the user’s language requirements.
Finally, you need to declare the tableView:sortDescriptorsDidChange: method in your Table View Controller in the format shown below:
-(void)tableView:(NSTableView *)mtableView sortDescriptorsDidChange:(NSArray *)oldDescriptors
{
[listArray sortUsingDescriptors: [mtableView sortDescriptors]];
[tableView reloadData];
}
Just had lately the same issue to get tableView sorted.
My approach :
bind your sortDescriptors to tableview's arrayController
bind tableview's sortDescriptors to Arraycontroller's sort descriptor
perform the settings in attribute inspector (see Tosin's answer above)
Worked perfect for me. No need to set prototypes for columns or something else.
Thanks very much ,It is usefullly for my question.
my code like this
First, set unique values in the XIB interface,like name...
- (void)viewDidLoad {
[super viewDidLoad];
self.itemTableView.dataSource = self;
self.itemTableView.delegate = self;
self.itemTableView.selectionHighlightStyle = NSTableViewSelectionHighlightStyleRegular;
self.itemTableView.usesAlternatingRowBackgroundColors = YES;
for (NSTableColumn *tableColumn in self.itemTableView.tableColumns ) {
NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:tableColumn.identifier ascending:NO selector:#selector(compare:)];
[tableColumn setSortDescriptorPrototype:sortDescriptor];
}
}
-(void)tableView:(NSTableView *)tableView sortDescriptorsDidChange:(NSArray<NSSortDescriptor *> *)oldDescriptors{
NSLog(#"sortDescriptorsDidChange:%#",oldDescriptors);
[self.itemArr sortUsingDescriptors:[tableView sortDescriptors]];
[self.itemTableView reloadData];
}

Update predicate on arraycontroller

I have an array controller and I have bound an entity to it, sort descriptor and predicate.
If I change the predicate format when the app runs, it works, so the binding is working.
My problem is when I want to change the predicate, f.ex. with a search term or some string that a user inputs, nothing happens, but when I add a record to the core data database, the tableview does update.
So my question is, how do I tell the array controller that the predicate has changed and it should update itself. Here is a code that runs when I enter search term, it also works, and I get all the NSLogs output correctly. Just my tableview is not updating itself.
- (IBAction)didChangeSearch:(id)sender {
if (sender == searchField) {
NSString *searchterm = [sender stringValue];
if (searchterm.length > 1) {
predicate = [NSPredicate predicateWithFormat:#"name contains [c]%#", #"m"];
NSLog(#"Putting predicate to the job : %#", searchterm);
} else {
predicate = nil;
NSLog(#"There is nolonger any predicate");
}
}
NSLog(#"I just got %#", [sender stringValue]);
}
I would like to say in the start that I am very new to bindings, have never used them until tonight, got a good feeling for them, and liked it, saves me so much code and I finally understood it (as much as 1 day can).
You should use self.predicate = ..... This will ensure that the proper KVO notifications are sent out, which will make your tableview update immediately (this assumes that "predicate" is a property and is bound to your array controller's filter predicate binding).

Iterate over NSTableview or NSArrayController to get data

I have an NSTableview which s bound to a NSArrayController. The Table/Arraycontroller contains Core Data "Person" entities. The people are added to the NSTableview by the GUI's user.
Let's say a person entity looks like
NSString* Name;
int Age;
NSString* HairColor;
Now I want to iterate over what is stored in the array controller to perform some operation in it. The actual operation I want to do isn't important I don't really want to get bogged down in what I am trying to do with the information. It's just iterating over everything held in the NSArraycontroller which is confusing me. I come from a C++ and C# background and am new to Cocoa. Let's say I want to build a NSMutableArray that contains each person from nsarraycontroller 1 year in the future.
So I would want to do something like
NSMutableArray* mutArray = [[NSMutableArray alloc] init];
foreach(PersonEntity p in myNsArrayController) // foreach doesn't exist in obj-c
{
Person* new_person = [[Person alloc] init];
[new_person setName:p.name];
[new_person setHairColor:p.HairColor];
[new_person setAge:(p.age + 1)];
[mutArray addObject:new_person];
}
I believe the only thing holding me back from doing something like the code above is that foreach does not exist in Obj-c. I just don't see how to iterate over the nsarraycontroller.
Note: This is for OSX so I have garbage collection turned on
You're looking for fast enumeration.
For your example, something like
for (PersonEntity *p in myNsArrayController.arrangedObjects)
{
// Rest of your code
}
You can also enumerate using blocks. For example:
[myNsArrayController enumerateObjectsUsingBlock:^(id object, NSUInteger index, BOOL *stop)
{
PersonEntity *p = object;
// Rest of your code
}];
There's pro's and cons to both approaches. These are discussed in depth in the answer to this question:
Objective-C enumerateUsingBlock vs fast enumeration?
You can find a great tutorial on blocks in Apple's WWDC 2010 videos. In that they say that at Apple they use blocks "all the time".

View Based Table Cells on OS X not showing data properly

So I admit to being a total noob to cocoa, so I offer a noob question. I'm probably just missing the dumb obvious somewhere but i just cant seem to get my table to populate data.
I'm following the table view playground example but everytime i try to mimic the Basic TableView Window the first row becomes the height of the number of rows i added (at least thats what it looks like. Here is my code:
- (id)tableView:(NSTableView *)tableView objectValueForTableColumn:(NSTableColumn *)tableColumn row:(int)row
{
NSString *identifier = [tableColumn identifier];
if ([identifier isEqualToString:#"filename"]) {
// We pass us as the owner so we can setup target/actions into this main controller object
NSTableCellView *cellView = [fileBrowserTable makeViewWithIdentifier:identifier owner:self];
// Then setup properties on the cellView based on the column
cellView.textField.stringValue = [fileList filenameAtIndex:row];
cellView.imageView.objectValue = [[NSWorkspace sharedWorkspace] iconForFile:[fileList fullPathAtIndex:row]];
return cellView;
}
else if ([identifier isEqualToString:#"path"]) {
NSTextField *textField = [fileBrowserTable makeViewWithIdentifier:identifier owner:self];
textField.objectValue = [fileList pathAtIndex:row];
return textField;
}
else if ([identifier isEqualToString:#"preview"]) {
NSTextField *textField = [fileBrowserTable makeViewWithIdentifier:identifier owner:self];
textField.objectValue = [fileList previewAtIndex:row];
return textField;
}
return nil;
}
I think its worth mentioning that when using a the old school text field cell, I have no problems displaying data (of course the above code is different in that case) so im positive sure its not a problem with my data structure that holds the values. I have also set the correct delegate and data source
The cell using the 'filename' identifier uses the 'image and text table view cell' while the others use just a 'text table cell view'. Neither of them work so i'm guessing something is wrong with how I set my table up. But when comparing my table with that of the example, it's just a spitting reflection (minus identifiers file names).
One thing that I notice that I can't quite figure out is that the example says:
The NSTableView has two reuse identifier assocations: "MainCell" and "SizeCell" are both associated with the nib ATBasicTableViewCells.xib
I don't really understand this statement. However that being said, the example doesn't contain any ATBasicTableViewCells.xib nor does it have any associations with it (code or ib) that I can find.
Have you tried to set the rowSizeStyle of the NSTableView to NSTableViewRowSizeStyleCustom?
[UPDATE] Re-reading your question, it's not clear for me what your problem is. The solution I have given is related to problems with the size of each cell which is not taken into account unless the rowSizeStyle is set to custom.

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