NSTableView + Delete Key - objective-c

I'm looking for an easy solution to delete NSTableView rows by pushing the delete key.
All I have seen when searching in Google were answers like this:
http://likethought.com/lockfocus/2008/04/a-slightly-improved-nstableview/
This seems to me an Engineering solution, but I would like to know if this is the best way. Does any one know a better answer?

What I usually do is create a new menu item in your application's menu bar. Something like:
File -> Delete ${Name of Item}
Then you can link that NSMenuItem in Interface Builder to point to an IBAction method defined somewhere on either your app delegate or some other controller. The implementation for this method should delete the item from your model, and refresh the NSTableView.
The advantage to making an NSMenuItem out of the action is that:
You can give the item a keyboard shortcut in Interface Builder. (Like the delete key.)
Users who are not familiar with your application, afraid to press the delete key, or do not have access to a keyboard for whatever reason, can still make use of this functionality.

I've implemented something similar to LTKeyPressTableView. However, I use array controllers, so in my subclass I added IBOutlet NSArrayController * relatedArrayController. Instead of handling delete request in a delegate, I handle it directly in the subclass since my subclass specifically deals with adding handling of Delete key. When I detect keypress for delete key, I'm just calling [relatedArrayController delete:nil];.
IRTableView.h:
#import <Cocoa/Cocoa.h>
#interface IRTableView : NSTableView {
IBOutlet NSArrayController * relatedArrayController;
}
#end
and IRTableView.m:
#import "IRTableView.h"
#implementation IRTableView
- (void)keyDown:(NSEvent *)event
{
// Based on LTKeyPressTableView.
//https://github.com/jacobx/thoughtkit/blob/master/LTKeyPressTableView
id delegate = [self delegate];
// (removed unused LTKeyPressTableView code)
unichar key = [[event charactersIgnoringModifiers] characterAtIndex:0];
if(key == NSDeleteCharacter)
{
if([self selectedRow] == -1)
{
NSBeep();
}
BOOL isEditing = ([[self.window firstResponder] isKindOfClass:[NSText class]] &&
[[[self.window firstResponder] delegate] isKindOfClass:[IRTableView class]]);
if (!isEditing)
{
[relatedArrayController remove:nil];
return;
}
}
// still here?
[super keyDown:event];
}
#end
End result is quite IB-friendly for me, and a quite simple solution for use in a Cocoa Bindings+Core Data application.

There is no need to subclass and catch keyDown in NSViewController.
The Delete menu item in the menu Edit is connected to the selector delete: of First Responder. If there is no Delete menu item, create one and connect it to delete: of First Responder (red cube).
Assign a key equivalent to the Delete menu item (⌫ or ⌘⌫)
In the view controller implement the IBAction method
Swift: #IBAction func delete(_ sender: AnyObject)
Objective-C: -(IBAction)delete:(id)sender
and put in the logic to delete the table view row(s).

After 10.10, NSViewController is part of the responder chain. So the easiest way is to implement keyDown in your subclassed NSViewController

Related

NSWindow, press key ENTER: how to limit the key listening to the focused NSControl?

I have an NSWindow with a main "OK" button. This button has as "key equivalent" property in interface builder, the key ENTER i.e ↵.
It works good, but now I have a new NSComboBox, which is supposed to invoke a method when the user selects a list item, or he preses Enter / ↵.
However, when I press Enter, the main Button receive the notification and the window close. How to prevent this?
This is the normal behavior what you are getting, but you can hack a bit, by removing and adding the key-equivalent.
Add following delegates of NSComboBox:
- (void)comboBoxWillPopUp:(NSNotification *)notification;{
[self.closeButton setKeyEquivalent:#""];
}
- (void)comboBoxWillDismiss:(NSNotification *)notification;{
[self.closeButton setKeyEquivalent:#"\r"];
}
One way you can workaround for prevent enter notification is like that below:-
//Connect this action method to your combobbox and inside that set one BOOL flag to yes
- (IBAction)comBoxItm:(id)sender
{
self.isEnterCalled=YES;
}
//Now check this flag to your some method where close window is called
-(void)someMethod
{
//Check the flag value if it is yes then just ignore it
if (!self.isEnterCalled)
{
//Close window logic
}
self.isEnterCalled=NO;
}
Ran into the same problem. Had "hot key" which I'd like to switch off while editing some text fields. I found solution for myself. There's no need in override lots of NSTextField base methods.
Firstly, I removed all the "key equivalents". I used to detect Enter key down with the + (void)addLocalMonitorForEventsMatchingMask:(NSEventMask)mask handler:(NSEvent *(^)(NSEvent *))block class method of NSEvent. You pass block as a parameter, where you can check for some conditions. The first parameter is the event mask. For your task it would be NSKeyDownMask, look for other masks at the NSEvent Reference Page
The parameter block will perform each time the user pushes the button. You should check if it is right button pushed, and - generally - if the current window first responder isn't some editable control. For that purposes we need NSWindow category class just not to implement this code each time we deal with NSKeyDownMasked local monitors.
NSWindow+Responders class listing:
#interface NSWindow (Responders)
- (BOOL)isEditableFirstResponder;
#end
#implementation NSWindow (Responders)
- (BOOL)isEditableFirstResponder
{
if (!self.firstResponder)
return NO; // no first responder at all
if ([self.firstResponder isKindOfClass:[NSTextField class]]) // NSComboBox is NSTextField subclass
{
NSTextField *field=(NSTextField *)self.firstResponder;
return field.isEditable;
}
if ([self.firstResponder isKindOfClass:[NSButton class]]) // yep, buttons may be responders
return YES;
return NO; // the first responder is not NSTextField or NSButton subclass - not editable
}
#end
Don't know if there's another way to check if we are now editing some text field or combo box. So, there's at least the part you add the local monitor somewhere in your class (NSWindow, NSView, some controller etc.).
- (void)someMethod
{
id monitor=[NSEvent addLocalMonitorForEventsMatchingMask:NSKeyDownMask handler:(NSEvent *)^(NSEvent *theEvent){
if (theEvent.keyCode==/*Enter key code*/ && ![self.window.isEditableFirstResponder]) // you should check the key modifiers too
{
// your code here
}
return theEvent; // you may return the event to pass the key to the receiver
}];
}
Local monitors is safe remedy about the Apple rules. It works only inside your application. For global key down events you may use addGlobalMonitor but Apple may reject your app from the AppStore.
And don't forget to remove the monitor when there's no need in it.
- (void)viewControllerShutdownMethod
{
[NSEvent removeMonitor:monitor];
}
Good luck.

How to get a reference to the view controller of a superview?

Is there a way to get a reference to the view controller of my superview?
There were several instances that I needed this on the past couple of months, but didn't know how to do it. I mean, if I have a custom button on a custom cell, and I wish to get a reference of the table view controller that controls the cell I`m currently in, is there a code snippet for that? Or is it something that I should just solve it by using better design patterns?
Thanks!
Your button should preferably not know about its superviews view controller.
However, if your button really needs to message objects that it shouldn't know the details about, you can use delegation to send the messages you want to the buttons delegate.
Create a MyButtonDelegate protocol and define the methods that everyone that conforms to that protocol need to implement (the callback). You can have optional methods as well.
Then add a property on the button #property (weak) id<MyButtonDelegate> so that any class of any kind can be set as the delegate as long as it conforms to your protocol.
Now the view controller can implement the MyButtonDelegate protocol and set itself as the delegate. The parts of the code that require knowledge about the view controller should be implemented in the delegate method (or methods).
The view can now send the protocol messages to its delegate (without knowing who or what it is) and the delegate can to the appropriate thing for that button. This way the same button could be reused because it doesn't depend on where it is used.
When I asked this question I was thinking of, in a situation where I have custom cells with buttons on them, how can the TableViewController know which cell's button was tapped.
More recently, reading the book "iOS Recipes", I got the solution:
-(IBAction)cellButtonTapped:(id)sender
{
NSLog(#"%s", __FUNCTION__);
UIButton *button = sender;
//Convert the tapped point to the tableView coordinate system
CGPoint correctedPoint = [button convertPoint:button.bounds.origin toView:self.tableView];
//Get the cell at that point
NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint:correctedPoint];
NSLog(#"Button tapped in row %d", indexPath.row);
}
Another solution, a bit more fragile (though simpler) would be:
- (IBAction)cellButtonTapped:(id)sender
{
// Go get the enclosing cell manually
UITableViewCell *parentCell = [[sender superview] superview];
NSIndexPath *pathForButton = [self.tableView indexPathForCell:parentCell];
}
And the most reusable one would be to add this method to a category of UITableView
- (NSIndexPath *)prp_indexPathForRowContainingView:(UIView *)view
{
CGPoint correctedPoint = [view convertPoint:view.bounds.origin toView:self];
return [self indexPathForRowAtPoint:correctedPoint];
}
And then, on your UITableViewController class, just use this:
- (IBAction)cellButtonTapped:(id)sender
{
NSIndexPath *pathForButton = [self.tableView indexPathForRowContainingView:sender];
}
If you know which class is the superview of your view controller, you can just iterate through the subviews array and typecheck for your superclass.
eg.
UIView *view;
for(tempView in self.subviews) {
if([tempView isKindOfClass:[SuperViewController class] ])
{
// you got the reference, do waht you want
}
}

NSTextField not calling delegate when inside an NSTableCellView

I have a fairly vanilla Source List (dragged out from the Object Library) in my app, with an NSTreeController as its data source. I set the NSTextField inside the DataCell to be editable, but I want to be able to turn that off for some cells. The way I figured you would do this, is with a delegate for the NSTextField, but none of the delegate methods I've tried get called. Is there something I'm missing? I have the delegate set with an outlet in my XIB, and it happens to be the delegate to the owner NSOutlineView, as well, implementing both the NSOutlineViewDelegate and NSTextFieldDelegate protocols.
Also, I can't use the old –outlineView:shouldEditTableColumn:item: NSOutlineViewDelegate method either, since that only works with cell-based Outline Views (I'm assuming this is the case - the Outline View documentation doesn't appear to have been updated for Lion, though the analogous NSTableView documentation has, and those methods don't get called either).
Update
I reproduced this in a brand new test project, so it's definitely not related to any of my custom classes. Follow the steps below to create my sample project, and reproduce this problem.
In Xcode 4.1, create a new project, of type Mac OS X Cocoa Application, with no special options selected
Create two new files, SourceListDataSource.m and SourceListDelegate.m, with the contents specified below
In MainMenu.xib, drag a Source List onto the Window
Drag two Objects onto the dock (left side of the window), specifying the SourceListDataSource class for one, and the SourceListDelegate for the other
Connect the Outline View's dataSource and delegate outlets to those two objects
Select the Static Text NSTextField for the DataCell view inside the outline view's column
Turn on its Value binding, keeping the default settings
Connect its delegate outlet to the Source List Delegate object
Set its Behavior property to Editable
Build and Run, then click twice on either cell in the outline view.
Expected: The field is not editable, and there is a "well, should I?" message in the log
Actual: The field is editable, and no messages are logged
Is this a bug in the framework, or am I supposed to achieve this a different way?
SourceListDataSource.m
#import <Cocoa/Cocoa.h>
#interface SourceListDataSource : NSObject <NSOutlineViewDataSource>
#property (retain) NSArray *items;
#end
#implementation SourceListDataSource
#synthesize items;
- (id)init
{
self = [super init];
if (self) {
items = [[NSArray arrayWithObjects:#"Alo", #"Homora", nil] retain];
}
return self;
}
- (id)outlineView:(NSOutlineView *)outlineView child:(NSInteger)index ofItem:(id)item {
if (!item) {
return [self.items objectAtIndex:index];
}
return nil;
}
- (NSInteger)outlineView:(NSOutlineView *)outlineView numberOfChildrenOfItem:(id)item {
return !item ? self.items.count : 0;
}
- (BOOL)outlineView:(NSOutlineView *)outlineView isItemExpandable:(id)item {
return NO;
}
- (id)outlineView:(NSOutlineView *)outlineView objectValueForTableColumn:(NSTableColumn *)tableColumn byItem:(id)item {
return item;
}
#end
SourceListDelegate.m
#import <Foundation/Foundation.h>
#interface SourceListDelegate : NSObject <NSOutlineViewDelegate, NSTextFieldDelegate> #end
#implementation SourceListDelegate
- (NSTableRowView *)outlineView:(NSOutlineView *)outlineView viewForTableColumn:(NSTableColumn *)tableColumn item:(id)item {
return [outlineView makeViewWithIdentifier:#"DataCell" owner:self];
}
- (BOOL)control:(NSControl *)control textShouldBeginEditing:(NSText *)fieldEditor {
NSLog(#"well, should I?");
return NO;
}
#end
Subclass NSTableCellView, with an outlet for the text field, and set the text field delegate in awakeFromNib. After doing that, control:textShouldBeginEditing: gets called. I'm not sure why, but (edit:) if you set the delegate in the xib, the delegate methods aren't called – I had the same experience as you.
Alternatively, you can forego the delegate and conditionally set Editable using a binding, either to a boolean property of the model, or using a value transformer which acts on a model instance and returns a boolean. Use the Editable binding of the text field.
I've encountered this problem, too. Because I didn't want to lose the bindings, I did the following:
Binding editable of the TextField to the objectValue and set up a custom NSValueTransformer subclass.
The other proposed solutions above are not performant and will not work on modern versions of macOS. NSTableView calls acceptsFirstResponder on EVERY textField in the entire table when one is about to be edited. And first responder methods get called while you just scroll around the table. If you put some logging in those calls, you'll see them in action.
Additionally, assigning the textField's delegate anywhere other than IB is not needed and won't actually work because NSTableView (and therefore NSOutlineView) basically "take over" for the views they contain.
The Correct, Modern Approach:
Subclass NSTableView (or NSOutlineView) and do this:
final class MyTableView: NSTableView
{
override func validateProposedFirstResponder(_ responder: NSResponder, for event: NSEvent?) -> Bool
{
// NSTableView calls -validateProposedResponder on cellViews' textFields A METRIC TON, even while just scrolling around, therefore
// do not interfere unless we're evaluating a CLICK on a textField.
if let textField: NSTextField = responder as? NSTextField,
(event?.type == .leftMouseDown || event?.type == .rightMouseDown)
{
// Don't just automatically clobber what the TableView returns; it'll return false here when delays are needed for double-actions, etc.
let result: Bool = super.validateProposedFirstResponder(responder, for: event)
// IF the tableView thinks this textField should edit, now we can ask the textField's delegate to confirm that.
if result == true
{
print("Validate first responder called: \(responder).")
return textField.delegate?.control?(textField, textShouldBeginEditing: textField.window?.fieldEditor(true, for: nil) ?? NSText()) ?? result
}
return result
}
else
{
return super.validateProposedFirstResponder(responder, for: event)
}
}
}
Notes:
This was written against macOS 11.3.1 and Xcode 12.5 for an application targeting macOS 11.
The isEditable property of the NSTextFields in your NSTableCellViews must be set to true. NSTableView's implementation of -validateFirstResponder will check that property first, so you need not do so in your delegate method.

UIViewController parentViewController access properties

I know this question has been asked several times and I did read existing posts on this topic but I still need help.
I have 2 UIViewControllers - parent and child. I display the child UIViewController using the presentModalViewController as below:
ChildController *child =
[[ChildController alloc] initWithNibName:#"ChildView" bundle:nil];
[self presentModalViewController:child animated:YES];
[child release];
The child view has a UIPickerView. When user selects an item from UIPickerView and clicks done, I have to dismiss the modal view and display the selected item on a UITextField in the parent view.
In child's button click delegate, I do the following:
ParentController *parent =
(ParentController *)[self.navigationController parentViewController];
[parent.myTextField setText:selectedText];
[self dismissModalViewControllerAnimated:YES];
Everything works without errors. But I don't know how to load the parent view so that it displays the updated UITextField.
I tried
[parent reloadInputViews];
doesn' work. Please help.
Delegation is the way to go. I know some people that may be looking for an easier solution but trust me I have tried others and nothing works better than delegation. So anyone having the same problem, go read up on delegation and follow it step by step.
In your subviewcontroller.h - declare a protocol and declare delegate mthods in it.
#protocol myDelegate
-(void)clickedButton:(subviewcontroller *)subController;
#end
In your subviewcontroller.h, within #interface:
id<myDelegate> delegate;
#property (nonatomic, assign) id<myDelegate> delegate;
NSString *data;
-(NSString *)getData;
In your subviewcontroller.m, synthesize myDelegate. Add the following code to where you want to notify your parentviewcontroller that the subview is done doing whatever it is supposed to do:
[delegate clickedButton:self];
and then handle getData to return whatever data you want to send to your parentviewcontroller
In your parentviewcontroller.h, import subviewcontroller.h and use it's delegate
#import "subviewcontroller.h"
#interface parentviewcontroller : VUIViewController <myDelegate>
{}
In your parentviewcontroller.m, implement the delegate method
- (void)clickedButton:(subviewcontroller *)subcontroller
{
NSString *myData = [subcontroller getData];
[self dimissModalViewControllerAnimated:YES];
[self reloadInputViews];
}
Don't forget memory management!
If a low-memory warning comes in during your modal view's display, the parent's view will be unloaded. Then parent.myTextField is no longer referring to the right text field until the view is reloaded. You can force a reload of the view just by calling parent.view;
However, a better idea might be to have the parent view have a String property that can be set by the child view. Then, when the parent view reappears, put that data into the text field, inside viewWillAppear: for example. You'd want to have the value set to some default value for when the parent view initially shows up too.
-(void) viewWillAppear:(BOOL) animated doesn't get called for me either, exactly when it's a modal view controller. No idea why. Not incorrectly overridden anywhere in this app, and the same problem occurs on the other 2 apps I'm working on. I really don't think it works.
I've used the delegate approach before, but I think that following approach is pretty good as well.
I work around this by adding a private category to UIViewController, like so:
.h file:
#interface UIViewController(Extras)
// returns true if this view was presented via presentModalViewController:animated:, false otherwise.
#property(readonly) BOOL isModal;
// Just like the regular dismissModalViewController, but actually calls viewWillAppear: on the parent, which hasn't been working for me, ever, for modal dialogs.
- (void)dismissModal: (BOOL) animated;
#end
and .m file:
#implementation UIView(Extras)
-(BOOL) isModal
{
return self == self.parentViewController.modalViewController;
}
- (void)dismissModal: (BOOL) animated
{
[self.parentViewController viewWillAppear: animated];
[self dismissModalViewControllerAnimated: animated];
}
#end
which I can now call like this when I want to dismiss the dialog box:
// If presented as a modal view, dismiss yourself.
if(self.isModal)
[self dismissModal: YES];
and now viewWillAppear is correctly called.
And yes, I'm donating a bonus 'isModal' property, so that the modal view can tell how it was being presented, and dismiss itself appropriately.

NSTableView keyDown: and mouseDown:

I've been working on a menubar note-taking application for Mac. It is written in Objective-C and Cocoa, and I'm using BWToolkit with it. My problem is getting keyDown: and mouseDown: events in a BWTransparentTableView which is a subclass of NSTableView. I just can't get it to work. I've tried searching the Internet, and some places say that you must subclass NSTableView. I've tried that, but it still doesn't work. I am pretty new to Objective-C and Cocoa, and I may just be doing something incorrectly.
Items in an NSTableView will automatically begin editing when they are slow double-clicked or when the Return key is pressed. Make sure that the table view, the cell and the array controller (if used) are marked as editable.
If you are not using an NSArrayController, make sure that your table view has a delegate and that it responds to tableView:shouldEditTableColumn:row:.
To handle a double click, you just need to set the doubleAction of the table view:
- (void)awakeFromNib
{
[tableView setTarget:self];
[tableView setDoubleAction:#selector(doubleClickInTable:)];
}
- (void)doubleClickInTable:(id)sender
{
NSInteger rowIndex = [sender selectedRow]; //Use selectedRowIndexes if you're supporting multiple selection
//Handle the double click
}
Note that neither of these methods require you to subclass NSTableView.