I use a view-based NSOutlineView to display and select hierarchically structured items for a scientific application.
Each row in the outline column represents an item, signified by an item-specific icon (all the same in the picture), a checkbox that shows if the item is selected, and the name of the item. I need the icon, the checkbox and the name to appear in the same cell, hence I am using a view-based NSOutlineView.
I have implemented the NSOutlineViewDataSource protocol to supply data to the the outline view.
The method outlineView:objectValueForTableColumn:byItem: supplies a custom object that has the properties BOOL selected and NSString *name.
My custom table cell view in IB is composed as follows:
I bound the check box value to objectValue.selected and the label value to objectValue.name.
As I hoped, the outline view displays nicely the name and selection state supplied by the objectValue.
However, if I change the state of the check box, the method outlineView:setObjectValue:forTableColumn:byItem: that is defined in the NSOutlineViewDataSource protocol is not triggered in my dataSource to supply the newly changed object value. Note that if I don't use a custom view for the cell this works.
I checked whether the table cell view's objectValue.selected actually gets changed when clicking the check box by inserting an NSLog statement into the setSelected method of the object that is passed as objectValue. The selected member changes state correctly.
How do I propagate the change of the objectValue back to my dataSource's model? I have checked the NSOutlineView's delegate methods, but can't find a way to signal that the cell view's objectValue was changed by my check box (i.e., that the cell view has "ended editing"). Is there some other fundamental point I am missing?
setObjectValue doesnt work for view based ones:
from header::
/* View Based OutlineView: This method is not applicable.
*/
- (void)outlineView:(NSOutlineView *)outlineView setObjectValue:(id)object forTableColumn:(NSTableColumn *)tableColumn byItem:(id)item;
I was able to solve this problem by creating a subclass of NSTableCellView, making it the delegate of the contained NXTextField, and using the edited value to update NSTableCellView's object value.
class CategoryNameTableViewCell : NSTableCellView, NSTextFieldDelegate {
func control(_ control: NSControl, textShouldEndEditing fieldEditor: NSText) -> Bool {
guard var category = self.objectValue as! Category? else {
Swift.print("Tried to edit category cell with no object!")
return false
}
category.name = control.stringValue
category.saveChanges()
return true
}
}
Related
I have a custom UITableViewCell and a custom UITextField, with the text field inside the table view cell.
I need to do some validation on text entered in the field, and display a little tick or cross image in the cell depending on if the text entered was okay.
My table view cell class imports the text field's header, and declares a .textField property which I can use.
My text field class has a class extension (#class) of my table view cell, and declares a .cell property, which I'd like to be able to use to access the cell's image, and display / update it to the tick or cross.
The text field's delegate is my view controller, and I'm using textFieldDidEndEditing in the following way to attempt to set that image (validationConfirmation). However, it's not working, nothing's happening, no error, etc.
Any idea what I'm doing wrong? This is a puzzler.
- (void)textFieldDidEndEditing:(UITextField *)textField
{
SignUpTextField *tf = (SignUpTextField *)textField;
if (textField.text.length < 6) {
tf.cell.validationConfirmation.hidden = NO;
tf.cell.validationConfirmation.image = [UIImage imageNamed:#"cross.png"];
}
}
So here, I'm getting the text field subclass (SignUpTextField, or I'm attempting to), and trying to set its cell property's image property. Is this wrong? Messy? Bad practise?
You don't need to (and you shouldn't) have a cell reference inside textField class. I believe your textField is added as a subview of the cell. Hence in the textFieldDidEndEditing: method, you can get the cell using textField.superview. Or alternately, you can assign a tag to the textField corresponding to the tableview row that it appears in and access the cell using cellForRowAtIndexPath: method of tableview where you can use the tag to create your indexpath.
I have an NSOutlineView that is bound to an NSTreeController. When I click on a row in the NSOutlineView, nothing happens, that is, it is not selected. However, when I insert an object using add: in the tree controller, the inserted item is highlighted. I think the problem with the rows not being selectable has to do with the bindings but I can't find the problem. The have the NSOutlineView's 'Selection Index Paths' bound to the tree controller's selectionIndexPaths 'Controller Key'. Are there any other bindings that need to be configured? Do I need to have the Sort Description binding?
The NSOutlineView is actually a custom subclass, so I made the subclass its own delegate and implemented one of the delegate methods to see if they're being called:
-(void)awakeFromNib {
[self setDelegate:self];
}
- (BOOL)outlineView:(NSOutlineView *)outlineView shouldSelectItem:(id)item {
return YES;
}
A breakpoint on return YES shows me that the method is never called.
I’m using a regular (not subclassed) NSTableCellView in a view-based table view. It has the initial image and text field views. I added an NSStepper to the view.
The text field is bound to tableCellView.objectValue.quantity.
The stepper’s value is bound to tableCellView.objectValue.quantity too.
The problem is that when running the app, when I click the stepper it doesn’t seem to get the mouse event, neither arrow gets highlighted, the value is not incremented or decremented.
If I set the double action of the table view it gets triggered if I double-click the stepper as if it was transparent.
What am I missing?
Thanks!
You should look at the documentation but easiest is that you need to subclass NSTableView and override this method to validate the proposed first responder. As the document states NSTableViews disallow some controls to be used unless the row is first selected. Even then it still may discard some.
- (BOOL)validateProposedFirstResponder:(NSResponder *)responder forEvent:(NSEvent *)event {
return YES;
}
Further to the correct answer from Robert Payne, with Swift you could add an extension to NSTableView and not subclass it.
extension NSTableView {
override public func validateProposedFirstResponder(responder: NSResponder, forEvent event: NSEvent?) -> Bool {
return true
}
}
And I'd like to emphasis that it's the NSTableView not the NSTableViewCell.
Context:
I have an NSArrayController tied to Core Data that supplies rows for an NSTableView. When a user selects rows, the arrayController's "selectedObjects" property changes.
Now, each of those "selectedObjects" is a Core Data entity called "LPFile" that has an attribute called "style", which is an integer from 0 to 3. The "style" attribute should correspond to the selectedIndex of an NSPopUpButton.
My Question:
If a user selects multiple rows AND the LPFiles associated with these rows have the same value for "style", I would like the NSPopUpButton to set its "selectedIndex" property to that value. If the rows' objects have DIFFERENT values for "style", then the NSPopUpButton should display a blank row. (When the user then chooses a style, that blank row should disappear from the NSPopUpButton.)
I know how to achieve this by writing code manually and if selection was limited to a single row I could set up those bindings, but how do I set up the bindings to handle multiple selected objects that may or may not have different values for "style"? I've Googled quite a bit, but can't find specific info and I'm tired of experimenting! (Note: I provide the content items for the NSPopUpButton in IB, so I don't bind anything to the content bindings of the button.)
You'll probably have to write a little bit of code, but you can still use bindings to control the UI elements, in this case the popup button.
Here is one way to do it that has worked for me:
In the controller that provides the content for the array controller, define a property which contains the selection index set corresponding to the selection in the table view. Bind it to the array controller's selection index set, so it is always updated and sync'ed with the table view. For simplicity, I have called it fileSelectionIndexSet in the following.
Then, define a property that provides the index for the popup button. Below, I have called it styleIndex.
You can bind the popup buttons selection index to this property. You may have to provide its content from the controller, too. That would be a readonly property returning a static array of strings, for instance.
// Header file, just synthezise in implementation
#property (retain) NSInteger styleIndex;
Register the controller as an observer of its own fileSelectionIndexSet property:
// It doesn't have to be awakeFromNib, any method will do if called before
// you need the functionality
-(void)awakeFromNib
{
[self addObserver:self
forKeyPath: #"fileSelectionIndexSet"
options:NSKeyValueObservingOptionNew
context:NULL];
}
- (void) observeValueForKeyPath:(NSString *)keyPath
ofObject:(id)object
change:(NSDictionary *)change
context:(void *)context
{
if ( [keyPath isEqualToString: #"fileSelectionIndexSet"] )
{
NSInteger index;
index = ... // Compute value based on current LPFile selection
self.styleIndex = index;
}
}
Implementing self as an observer of its own property makes the styleIndex property a one-way dependant of the fileSelectionIndexSet.
This means that whenever the user changes the selection in the table view, the popup button is updated. However, when the user changes the selection in the popup button, nothing is changed in the table view.
I have a small NSTableView with a checkbox. Whenever the checkbox is not checked, I want one of the adjacent NSCells to be grayed out and inaccessible.
However, I can't figure out how to address only one specific cell. -dataCellForRow of NSTableColumn always changes the template cell for the whole table column.
How can I access one single cell?
Edit: I fill the table view using the NSTableViewDataSource protocol.
You don't "access a cell". NSTableView asks for data only when necessary, you don't populate it or control it directly.
Instead, you create a controller object which implements the NSTableViewDatasource and optionally NSTableViewDelegate protocols. The table view then sends the datasource messages to your controller and your controller supplies the appropriate data.
You can allow editing for an object displayed in the table view by implementing the ‑tableView:setObjectValue:forTableColumn:row: datasource method. This method will be called on your controller object when the user clicks the checkbox. It is your controller's responsibility to update the model appropriately.
When the model is updated, your controller should tell the table view to reload. The table view will then ask your controller for the value of any cell that requires display using the ‑tableView:objectValueForTableColumn:row: datasource method. This will include the cell that you need to disable. Your controller needs to supply the appropriate value for the cell.
If you need more control of the cell, you can implement the
‑tableView:willDisplayCell:forTableColumn:row: delegate method. This is called just before a cell is displayed, and you can modify the cell appropriately.
More info about using data sources is in the docs.
The other option (instead of using a datasource) is to use Cocoa Bindings and an NSArrayController that you bind to your collection of model objects. In that case, you can bind the Enabled binding of the table column to some property of your model object that controls the cell's enabled state. It is your responsibility to ensure that the state of that property is correct.
If you need to make the property dependent on the value of another property, you can use the dependent key mechanism outlined in the Key-Value Observing documentation.
Could you bind the editability of that column to the value that is being displayed in the checkbox? i.e. if it is checked, it is editable, otherwise it isn't?
I am trying to remember the exact editor interface, and I am not next to my Mac at home, so I am not able to do a total walk through on it - hope this can point you in the right direction.
Since SDK Version 10.7, there's -viewAtColumn:row:makeIfNecessary: on NSTableView. The majority of information I found on the web don't take the new methods into account, so here it is for all the others looking for an answer to this question.
From Mouse Event to Cell Selection
First, add a protocol for your controller to handle cell selection from a table view, like this:
#protocol XYZCellSelectionDelegate <NSObject>
- (void)cellViewWasSelectedAtRow:(NSInteger)row column:(NSInteger)column;
#end
Then subclass NSTableView and override -mouseDown:
// In your Custom Table View subclass:
- (void)mouseDown:(NSEvent *)event
{
NSPoint point = [self convertPoint:[event locationInWindow] fromView:nil];
NSInteger selectedRowIndex = [self rowAtPoint:point];
NSInteger selectedColumnIndex = [self columnAtPoint:point];
if ([self.calendarViewDelegate respondsToSelector:#selector(cellViewWasSelectedAtRow:column:)])
{
[self.calendarViewDelegate cellViewWasSelectedAtRow:selectedRowIndex column:selectedColumnIndex];
}
[super mouseDown:event];
}
Afterwards, you can use -viewAtColumn:row:makeIfNecessary: like this in the delegate/controller object:
- (void)cellViewWasSelectedAtRow:(NSInteger)row column:(NSInteger)column
{
NSView *selectedView = [self.tableView viewAtColumn:column row:row makeIfNecessary:YES];
// Do something with the cell to the right
NSInteger nextColumn = column + 1;
NSView *cellNextToIt = [self.calendarTableView viewAtColumn:nextColumn row:row makeIfNecessary:YES];
}
Note: Nowadays, I'd pass the table view to the delegate as a parameter instead of relying on the delegate to keep a reference to the table view.