I have a subclass of NBox that I would like to drag around a canvas called dragBox. I don't understand why draggingEntered isn't being fired on the following code. I get a nice slideback image, but none of the destination delegates are getting fired. Why?
-(void) awakeFromNib
{
[[self superview] registerForDraggedTypes:[NSArray arrayWithObject:NSFilenamesPboardType]];
}
-(void) mouseDown:(NSEvent *)theEvent
{
[self dragImage:[[NSImage alloc] initWithContentsOfFile:#"/Users/bruce/Desktop/Untitled-1.png"] at:NSMakePoint(32, 32) offset:NSMakeSize(0,0) event:theEvent pasteboard:[NSPasteboard pasteboardWithName:NSDragPboard] source:self slideBack:YES];
}
-(NSDragOperation)draggingUpdated:(id <NSDraggingInfo>)sender // validate
{
NSLog(#"Updated");
return [sender draggingSourceOperationMask];
}
- (NSDragOperation)draggingEntered:(id <NSDraggingInfo>)sender {
NSLog(#"Drag Entered");
return [sender draggingSourceOperationMask];
}
- (BOOL)performDragOperation:(id <NSDraggingInfo>)sender {
NSLog(#"Move Box");
[self setFrameOrigin:[sender draggingLocation]];
return YES;
}
-(BOOL) prepareForDragOperation:(id<NSDraggingInfo>)sender
{NSLog(#"Prepared");
return YES;
}
In your mouseDown method you are not putting anything in the pasteboard before you initiate the drag operation. The documentation for NSView states you need to add your data on the pasteboard before sending it to that message.
Whatever destination views you have are, or should be, registering for a certain drag type. If your pasteboard does not have any matching data for that type, the destinations will not fire any of the NSDraggingProtocol messages.
Solved!
I was using the NSBox as both a destination and source. The events weren't being fired when this was the case. I moved registerDragTypes to the superview, the canvas, and implemented the draggingEntered and performDrag there. It works now...
Bruce
Related
I'm trying to understand how best to impliment drag and drop of files from the Finder to a NSTableView which will subsequently list those files.
I've built a little test application as a proving ground.
Currently I have a single NSTableView with FileListController as it's datasourse. It's basically a NSMutableArray of File objects.
I'm trying to work out the best / right way to impliment the drag and drop code for the NSTableView.
My first approach was to subclass the NSTableView and impliment the required methods :
TableViewDropper.h
#import <Cocoa/Cocoa.h>
#interface TableViewDropper : NSTableView
#end
TableViewDropper.m
#import "TableViewDropper.h"
#implementation TableViewDropper {
BOOL highlight;
}
- (id)initWithCoder:(NSCoder *)aDecoder {
self = [super initWithCoder:aDecoder];
if (self) {
// Initialization code here.
NSLog(#"init in initWithCoder in TableViewDropper.h");
[self registerForDraggedTypes:#[NSFilenamesPboardType]];
}
return self;
}
- (BOOL)performDragOperation:(id < NSDraggingInfo >)sender {
NSLog(#"performDragOperation in TableViewDropper.h");
return YES;
}
- (BOOL)prepareForDragOperation:(id)sender {
NSLog(#"prepareForDragOperation called in TableViewDropper.h");
NSPasteboard *pboard = [sender draggingPasteboard];
NSArray *filenames = [pboard propertyListForType:NSFilenamesPboardType];
NSLog(#"%#",filenames);
return YES;
}
- (NSDragOperation)draggingEntered:(id <NSDraggingInfo>)sender
{
highlight=YES;
[self setNeedsDisplay: YES];
NSLog(#"drag entered in TableViewDropper.h");
return NSDragOperationCopy;
}
- (void)draggingExited:(id)sender
{
highlight=NO;
[self setNeedsDisplay: YES];
NSLog(#"drag exit in TableViewDropper.h");
}
-(void)drawRect:(NSRect)rect
{
[super drawRect:rect];
if ( highlight ) {
//highlight by overlaying a gray border
[[NSColor greenColor] set];
[NSBezierPath setDefaultLineWidth: 18];
[NSBezierPath strokeRect: rect];
}
}
#end
The draggingEntered and draggingExited methods both get called but prepareForDragOperation and performDragOperation don't. I don't understand why not?
Next I thought I'll subclass the ClipView of the NSTableView instead. So using the same code as above and just chaging the class type in the header file to NSClipView I find that prepareForDragOperation and performDragOperation now work as expected, however the ClipView doesn't highlight.
If I subclass the NSScrollView then all the methods get called and the highlighting works but not as required. It's very thin and as expected round the entire NSTableView and not just the bit below the table header as I'd like.
So my question is what is the right thing to sublclass and what methods do I need so that when I peform a drag and drop from the Finder, the ClipView highlights properly and prepareForDragOperation and performDragOperation get called.
And also when performDragOperation is successful how can this method call a method within my FileListController telling it to create a new File object and adding it to the NSMutableArray?
Answering my own question.
It seems that subclassing the NSTableView (not the NSScrollView or the NSClipView) is the right way to go.
Including this method in the subclass :
- (NSDragOperation)draggingUpdated:(id <NSDraggingInfo>)sender {
return [self draggingEntered:sender];
}
Solves the problem of prepareForDragOperation and performDragOperation not being called.
To allow you to call a method within a controller class, you make the delagate of your NSTextView to be the controller. In this case FileListController.
Then within performDragOperation in the NSTableView subclass you use something like :
NSPasteboard *pboard = [sender draggingPasteboard];
NSArray *filenames = [pboard propertyListForType:NSFilenamesPboardType];
id delegate = [self delegate];
if ([delegate respondsToSelector:#selector(doSomething:)]) {
[delegate performSelector:#selector(doSomething:)
withObject:filenames];
}
This will call the doSomething method in the controller object.
Updated example project code here.
I have the following code:
-(void)textFieldDidBeginEditing:(UITextField *)textField
{
CGRect textFieldRect = [self.view.window convertRect:textField.bounds fromView:textField];
CGRect viewRect = [self.view.window convertRect:self.view.bounds fromView:self.view];
...
}
As you can see it passes in a UITextField. I also have this code duplicated in the same ViewController but passing in a UITextView.
I want to be able to refactor this into a single method which passes in either the UITextField or UITextView? How can I do this?
Also this code appears in other View Controllers, so ideally I'd like to place it in a helper class, very new to iOS so not sure where to go from here.
I've removed most of the code from the method for brevity, but what it does is it slides the UI controls into view when the iOS keyboard appears.
You can expect UIView, as it seems you don't use any special text properties from those views.
-(void)textFieldDidBeginEditing:(UIView *)textField
{
CGRect textFieldRect = [self.view.window convertRect:textField.bounds fromView:textField];
CGRect viewRect = [self.view.window convertRect:self.view.bounds fromView:self.view];
// ...
}
Call a helper methods, that expects a UIView, the common super class.
-(void)textFieldDidBeginEditing:(UITextField *)textField
{
return [self textBeginEditing:textField];
}
-(void)textViewDidBeginEditing:(UITextView *)textView
{
return [self textBeginEditing:textView];
}
-(void)textBeginEditing:(UIView *)view
{
//and if you need to do something, where you need to now, if it is a textView or a field, use
if([view isKindOfClass:[UITextField class]]){
//…
} else if([view isKindOfClass:[UITextView class]]){
//…
}
}
I have an UIImageView with a method to change the image it displays. It works fine, if the method is triggered from a touch event received by the UIImageView itself, but the same method fails to update the UIImageView, if called from another object, which triggered the touch event. I have an NSLog call in the method in question and thus can see, that the method is called in both cases. But only in one case I can see the actual change of the image in the other case the view is not updated.
When it works, I do not need to setNeedsDisplay or setNeedsLayout, but that is what I tried to fix the problem. Setting needsDisplay and needsLayout in the UIImageView as well as its superview. To no avail. I can see, that the image is actually changed, if I rotate the device, which causes a refresh and I see, that the UIImageView indeed changed.
The superview calls the method eventAtLocation: on an OutletCollection using makeObjectsPerformSelector:withObject:
It sure looks like an embarrassing mistake on my part, but I can't figure it out since hours. I am running out of ideas what to try :-(
Here's the code in question:
- (void)eventAtLocation:(NSValue *)location
{
CGPoint loc = [self.superview convertPoint:[location CGPointValue] toView:self];
if ([self pointInside:loc withEvent:nil]) {
if (!self.isAnimating) {
[self autoSwapImage];
}
}
else{
if (self.isAnimating) {
[self cancelAnimation];
}
}
}
- (void)cancelAnimation
{
self.isAnimating = NO;
[NSObject cancelPreviousPerformRequestsWithTarget:self];
}
- (void) swapImage
{
currentImage++;
if (currentImage > numberOfImages)
currentImage = 1;
NSLog(#"set image to %i", currentImage);
self.image = [UIImage imageNamed:[NSString stringWithFormat:#"img_%i.jpg", currentImage]];
[self setNeedsDisplay];
}
- (void) autoSwapImage
{
self.isAnimating = YES;
[self swapImage];
[self performSelector:#selector(autoSwapImage) withObject:self afterDelay:0.1];
}
// The following works, but if eventAtLocation: is called form the superview swapImage gets called (-> NSLog output appears), but the view is not updated
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
//[self autoSwapImage];
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
//[NSObject cancelPreviousPerformRequestsWithTarget:self];
}
#end
It looks like you aren't actually setting the UIImageView's image, you are just setting self.image. You need to do something like
self.myImageView.image = [UIImage imageNamed:[NSString stringWithFormat:#"img_%i.jpg", currentImage]];
Also you'll want to put a check in that [UIImage imageNamed:] actually is returning an image, and that its not nil.
UIImage* image = [UIImage imageNamed:#"someImage"];
if(!image){
NSLog(#"%#",#"Image Not Found");
}
I have set up an NSCollectionView in a cocoa application. I have subclassed the collection view's NSCollectionViewItem to send me a custom NSNotification when one of its views it selected / deselected. I register to receive a notification within my controller object when this notification is posted. Within this method I tell the view that has just been selected that it is selected and tell it to redraw, which makes it shade itself grey.
The NSCollectionViewItem Subclass:
-(void)setSelected:(BOOL)flag {
[super setSelected:flag];
[[NSNotificationCenter defaultCenter] postNotificationName:#"ASCollectionViewItemSetSelected"
object:nil
userInfo:[NSDictionary dictionaryWithObjectsAndKeys:(ASListView *)self.view, #"view",
[NSNumber numberWithBool:flag], #"flag", nil]];}
The Controller Class (in the -(void)awakeFromNib Method):
//Register for selection changed notification
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(selectionChanged:)
name:#"ASCollectionViewItemSetSelected"
object:nil];
And the -(void)selectionChanged:(NSNotification *)notification method:
- (void)selectionChanged:(NSNotification *)notification {
// * * Must get the selected item and set its properties accordingly
//Get the flag
NSNumber *flagNumber = [notification.userInfo objectForKey:#"flag"];
BOOL flag = flagNumber.boolValue;
//Get the view
ASListView *listView = [notification.userInfo objectForKey:#"view"];
//Set the view's selected property
[listView setIsSelected:flag];
[listView setNeedsDisplay:YES];
//Log for testing
NSLog(#"SelectionChanged to: %d on view: %#", flag, listView);}
The application that contains this code requires there to be no empty selection within the collection view at any time. This is where i get my problem. I've tried checking when a view's selection is changed and reselecting it if there is no selection, and manually selecting the views using NSCollectionView's
-(void)setSelectionIndexes:(NSIndexSet *)indexes
But there is always a situation which occurs that causes there to be an empty selection in the collection view.
So I was wondering if there is an easier way to prevent an empty selection occurring in an NSCollectionView? I see no checkbox in interface builder.
Thanks in advance!
Ben
Update
I ended up just subclassing my NSCollectionView, and overriding the - (void)mouseDown:(NSEvent *)theEvent method. I only then sent the method [super mouseDown:theEvent]; if the click was in one of the subviews. Code:
- (void)mouseDown:(NSEvent *)theEvent {
NSPoint clickPoint = [self convertPoint:theEvent.locationInWindow fromView:nil];
int i = 0;
for (NSView *view in self.subviews) {
if (NSPointInRect(clickPoint, view.frame)) {
//Click is in rect
i = 1;
}
}
//The click wasnt in any of the rects
if (i != 0) {
[super mouseDown:theEvent];
}}
I ended up just subclassing my NSCollectionView, and overriding the - (void)mouseDown:(NSEvent *)theEvent method. I only then sent the method [super mouseDown:theEvent]; if the click was in one of the subviews. Code:
- (void)mouseDown:(NSEvent *)theEvent {
NSPoint clickPoint = [self convertPoint:theEvent.locationInWindow fromView:nil];
int i = 0;
for (NSView *view in self.subviews) {
if (NSPointInRect(clickPoint, view.frame)) {
//Click is in rect
i = 1;
}
}
//The click wasnt in any of the rects
if (i != 0) {
[super mouseDown:theEvent];
}}
I also wanted to avoid empty selection in my collection view.
The way I did it is also by subclassing, but I overrode -hitTest: instead of -mouseDown: to return nil in case the click wasn't on an item :
-(NSView *)hitTest:(NSPoint)aPoint {
// convert aPoint in self coordinate system
NSPoint localPoint = [self convertPoint:aPoint fromView:[self superview]];
// get the item count
NSUInteger itemCount = [[self content] count];
for(NSUInteger itemIndex = 0; itemIndex < itemCount; itemIndex += 1) {
// test the point in each item frame
NSRect itemFrame = [self frameForItemAtIndex:itemIndex];
if(NSPointInRect(localPoint, itemFrame)) {
return [[self itemAtIndex:itemIndex] view];
}
}
// not on an item
return nil;
}
Although I'm late to this thread, I thought I'd just chime in because I've had the same problem recently. I got around it using the following line of code:
[_collectionView setValue:#NO forKey:#"avoidsEmptySelection"];
There is one caveat: the avoidsEmptySelection property is not part of the official API although I think that it's pretty safe to assume that its the type of property that will stick around for a while.
I'm trying to figure out how this is done the right way. I've tried to depict the situation:
I'm adding a UITableView as a subview of a UIView. The UIView responds to a tap- and pinchGestureRecognizer, but when doing so, the tableview stops reacting to those two gestures (it still reacts to swipes).
I've made it work with the following code, but it's obviously not a nice solution and I'm sure there is a better way. This is put in the UIView (the superview):
-(UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
if([super hitTest:point withEvent:event] == self) {
for (id gesture in self.gestureRecognizers) {
[gesture setEnabled:YES];
}
return self;
}
for (id gesture in self.gestureRecognizers) {
[gesture setEnabled:NO];
}
return [self.subviews lastObject];
}
I had a very similar problem and found my solution in this SO question. In summary, set yourself as the delegate for your UIGestureRecognizer and then check the targeted view before allowing your recognizer to process the touch. The relevant delegate method is:
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer
shouldReceiveTouch:(UITouch *)touch
The blocking of touch events to subviews is the default behaviour. You can change this behaviour:
UITapGestureRecognizer *r = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(agentPickerTapped:)];
r.cancelsTouchesInView = NO;
[agentPicker addGestureRecognizer:r];
I was displaying a dropdown subview that had its own tableview. As a result, the touch.view would sometimes return classes like UITableViewCell. I had to step through the superclass(es) to ensure it was the subclass I thought it was:
-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch
{
UIView *view = touch.view;
while (view.class != UIView.class) {
// Check if superclass is of type dropdown
if (view.class == dropDown.class) { // dropDown is an ivar; replace with your own
NSLog(#"Is of type dropdown; returning NO");
return NO;
} else {
view = view.superview;
}
}
return YES;
}
Building on #Pin Shih Wang answer. We ignore all taps other than those on the view containing the tap gesture recognizer. All taps are forwarded to the view hierarchy as normal as we've set tapGestureRecognizer.cancelsTouchesInView = false. Here is the code in Swift3/4:
func ensureBackgroundTapDismissesKeyboard() {
let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(handleTap))
tapGestureRecognizer.cancelsTouchesInView = false
self.view.addGestureRecognizer(tapGestureRecognizer)
}
#objc func handleTap(recognizer: UIGestureRecognizer) {
let location = recognizer.location(in: self.view)
let hitTestView = self.view.hitTest(location, with: UIEvent())
if hitTestView?.gestureRecognizers?.contains(recognizer) == .some(true) {
// I dismiss the keyboard on a tap on the scroll view
// REPLACE with own logic
self.view.endEditing(true)
}
}
One possibility is to subclass your gesture recognizer (if you haven't already) and override -touchesBegan:withEvent: such that it determines whether each touch began in an excluded subview and calls -ignoreTouch:forEvent: for that touch if it did.
Obviously, you'll also need to add a property to keep track of the excluded subview, or perhaps better, an array of excluded subviews.
It is possible to do without inherit any class.
you can check gestureRecognizers in gesture's callback selector
if view.gestureRecognizers not contains your gestureRecognizer,just ignore it
for example
- (void)viewDidLoad
{
UITapGestureRecognizer *singleTapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(handleSingleTap:)];
singleTapGesture.numberOfTapsRequired = 1;
}
check view.gestureRecognizers here
- (void)handleSingleTap:(UIGestureRecognizer *)gestureRecognizer
{
UIEvent *event = [[UIEvent alloc] init];
CGPoint location = [gestureRecognizer locationInView:self.view];
//check actually view you hit via hitTest
UIView *view = [self.view hitTest:location withEvent:event];
if ([view.gestureRecognizers containsObject:gestureRecognizer]) {
//your UIView
//do something
}
else {
//your UITableView or some thing else...
//ignore
}
}
I created a UIGestureRecognizer subclass designed for blocking all gesture recognizers attached to a superviews of a specific view.
It's part of my WEPopover project. You can find it here.
implement a delegate for all the recognizers of the parentView and put the gestureRecognizer method in the delegate that is responsible for simultaneous triggering of recognizers:
func gestureRecognizer(UIGestureRecognizer, shouldBeRequiredToFailByGestureRecognizer:UIGestureRecognizer) -> Bool {
if (otherGestureRecognizer.view.isDescendantOfView(gestureRecognizer.view)) {
return true
} else {
return false
}
}
U can use the fail methods if u want to make the children be triggered but not the parent recognizers:
https://developer.apple.com/reference/uikit/uigesturerecognizerdelegate
I was also doing a popover and this is how I did it
func didTap(sender: UITapGestureRecognizer) {
let tapLocation = sender.locationInView(tableView)
if let _ = tableView.indexPathForRowAtPoint(tapLocation) {
sender.cancelsTouchesInView = false
}
else {
delegate?.menuDimissed()
}
}
You can turn it off and on.... in my code i did something like this as i needed to turn it off when the keyboard was not showing, you can apply it to your situation:
call this is viewdidload etc:
NSNotificationCenter *center = [NSNotificationCenter defaultCenter];
[center addObserver:self selector:#selector(notifyShowKeyboard:) name:UIKeyboardDidShowNotification object:nil];
[center addObserver:self selector:#selector(notifyHideKeyboard:) name:UIKeyboardWillHideNotification object:nil];
then create the two methods:
-(void) notifyShowKeyboard:(NSNotification *)inNotification
{
tap.enabled=true; // turn the gesture on
}
-(void) notifyHideKeyboard:(NSNotification *)inNotification
{
tap.enabled=false; //turn the gesture off so it wont consume the touch event
}
What this does is disables the tap. I had to turn tap into a instance variable and release it in dealloc though.