I've never dealt much with NSViews so I am at a loss on this. I have a custom class that contains an NSImage ivar. I also have a subclass of NSView that contains an array of instances of my custom class. The NSImage from the custom class gets drawn at the center of the NSView upon creation. I need to be able to drag that NSImage around the NSView freely.
I have implemented the following methods to get started:
-(void)mouseDown:(NSEvent *)theEvent
{
[self beginDraggingSessionWithItems: /* I don't know what to put here */
event:theEvent
source:self];
}
I have tried placing the NSImage object from my custom class in an array as the item to drag but an exception is raised. I also tried creating an NSDraggingItem to place in there but it could not write the object to the pasteboard and raised an exception.
-(void)draggingSession:(NSDraggingSession *)session willBeginAtPoint:(NSPoint)screenPoint
{
NSLog(#"began");
}
-(void)draggingSession:(NSDraggingSession *)session movedToPoint:(NSPoint)screenPoint
{
NSLog(#"moved");
}
-(void)draggingSession:(NSDraggingSession *)session endedAtPoint:(NSPoint)screenPoint operation:(NSDragOperation)operation
{
NSLog(#"ended");
}
These methods get called properly as I click and drag my mouse around my subclass of NSView however they are useless until I can get the object to move.
I believe the answer may be to create an NSDraggingItem for each image and use that to move them freely around the view however I could not get it to work with even one object and do not know how to properly implement this idea. Any help is appreciated.
Went through a lot of headache on this one but finally figured it out. Instead of using beginDraggingSessionWithItems:event:source I used dragImage:at:offset:event:pasteboard:source:slideBack:. I keep track of the coordinates of each image in the view and can tell whether a specific image was clicked on or not by utilizing the following method I wrote in mouseDown:
-(BOOL)clickedAtPoint:(NSPoint)point InsideRect:(NSRect)rect
{
if ((point.x < (rect.origin.x + rect.size.width) &&
point.y < (rect.origin.y + rect.size.height)) &&
point.x > rect.origin.x && point.y > rect.origin.y) {
return YES;
}
return NO;
}
Related
I have an animation using two views where I would call lockFocus and get at the graphics context of the second NSView with [[NSGraphicsContext currentContext] graphicsPort], and draw. That worked fine until macOS 10.14 (Mojave).
Found a reference here:
https://developer.apple.com/videos/play/wwdc2018/209/
At 22:40 they talk about the "legacy" backing store that has changed. The above lockFocus and context pattern was big on the screen, saying that that won't work any more. And that is true. lockFocus() still works, and even gets you the correct NSView, but any drawing via the context does not work any more.
Of course the proper way to draw in a view is via Nsview's drawRect. So I rearranged everything to do just that. That works, but, drawRect has already automatically cleared the "dirty" area for you, prior to calling your drawRect. If you used setNeedsDisplayInRect: it will even clear only those areas for you. But, it will also clear areas made up of more than one dirty rectangle. And, it clears rectangular areas, while I draw roundish objects, so I end up with too much cleared away (black area):
Is there a way to prevent drawRect to clear the background?
If not I will have switch to using the NSView's layer instead, and use updateLayer, or something.
Update: I am playing around with using the layers of NSView, returning TRUE for wantsLayer and wantsUpdateLayer, and implementing:
- (void)drawLayer:(CALayer *)layer inContext:(CGContextRef)ctx
That is only called when I do:
- (BOOL) wantsLayer { return YES; }
- (BOOL) wantsUpdateLayer { return NO; }
and use setNeedsDisplayInRect: or setNeedsDisplay:
Which indeed makes drawRect no longer called, but the same automatic background erase has already taken place by the time my drawLayer: is called. So I have not made any progress there. It really is the effect of setNeedsDisplayInRect, and not my drawing. Just calling setNeedsDisplayInRect causes these erases.
If you set:
- (BOOL) wantsLayer { return YES; }
- (BOOL) wantsUpdateLayer { return YES; }
the only thing that is called is:
- (void) updateLayer
which does not provide me with a context to draw.
I had some hope for:
self.layerContentsRedrawPolicy = NSViewLayerContentsRedrawNever;
The NSView doc says:
Leave the layer's contents alone. Never mark the layer as needing
display, or draw the view's contents to the layer. This is how
developer created layers (layer-hosting views) are treated.
and it does exactly that. It doesn't notify you, or call delegates.
Is there a way to have complete control over the content of an NSView/layer?
UPDATE 2019-JAN-27:
NSView has a method makeBackingLayer that is not there for nothing, I guess. Implemented that, and it seems to work, basically, but no output shows on screen. Hence the followup question: nsview-makebackinglayer-with-calayer-subclass-displays-no-output
Using NSView lockFocus and unlockFocus, or trying to access the window's graphics contents directly not working in macOS 10.14 anymore.
You can create an NSBitmapImageRep object and update drawing in this context.
Sample code:
- (void)drawRect:(NSRect)rect {
if (self.cachedDrawingRep) {
[self.cachedDrawingRep drawInRect:self.bounds];
}
}
- (void)drawOutsideDrawRect {
NSBitmapImageRep *cmap = self.cachedDrawingRep;
if (!cmap) {
cmap = [self bitmapImageRepForCachingDisplayInRect:self.bounds];
self.cachedDrawingRep = cmap;
}
NSGraphicsContext *ctx = [NSGraphicsContext graphicsContextWithBitmapImageRep:cmap];
NSAssert(ctx, nil);
[NSGraphicsContext setCurrentContext:ctx];
// Draw code here
self.needsDisplay = YES;
}
You can try overriding method isOpaque and return YES from there. This will tell OS that we draw all pixels ourselves and it do not need to draw the views/window at the back of our view.
- (BOOL)isOpaque {
return YES;
}
A bit of context first. Essentially I have a window that is covering the desktop. On it I have a few WebKit WebView views which allow user interaction. By deafult, as one would expect, when another application is active it does not receive these events (such as hovering, mouse entered, and clicking). I can make it work by clicking my window first, then moving the mouse, but this is not good for usability. I've also managed to make it activate the window when the cursor enters, but it's far from ideal and rather hacky.
So instead I'm trying to use a tracking area. At the moment on the WebViews superview I have this tracking area:
NSTrackingArea *trackingArea = [[NSTrackingArea alloc] initWithRect:[self visibleRect]
options:NSTrackingMouseEnteredAndExited | NSTrackingMouseMoved | NSTrackingInVisibleRect | NSTrackingActiveAlways
owner:self
userInfo:nil];
This works as I want it to, I'm receiving the all the mouse events. However, the WebViews don't seem to be responding as intended. JavaScript mouse move events only fire when I hold and drag, not just hover and drag.
I've tried using hitTest to get the correct view, but nothing seems to work. Here's an example method, I'm using the isHandlingMouse boolean because without it an infinite loop seemed to be created for some reason:
- (NSView *)handleTrackedMouseEvent: (NSEvent *)theEvent{
if(isHandlingMouse)
return nil;
isHandlingMouse = true;
NSView *hit = [self hitTest: theEvent.locationInWindow];
if (hit && hit != self) {
return hit;
}
return nil;
}
- (void)mouseMoved:(NSEvent *)theEvent{
NSView *hit = [self handleTrackedMouseEvent: theEvent];
if (hit){
[hit mouseMoved: theEvent];
}
isHandlingMouse = false;
}
The 'hit' view, is a WebHTMLView, which appears to be a private class. Everything seems like it should be working,but perhaps there's something I'm doing that's breaking it, or I'm sending the event to the WebHTMLView incorrectly.
Post a sample Xcode project to make it easier for people to test solutions to this problem.
I was doing something similar and it took a lot of trial and error to find a solution. You will likely need to subclass NSWindow and add - (BOOL)canBecomeKeyWindow { return YES; }, then whenever you detect the mouse is over your window, you might call [window orderFrontRegardless] just so it can properly capture the mouse events.
I am creating a tableview where I will have an UIImageViewinside a UITableViewCell that I would like to allow the user to zoom into. I have been able to create this effect inside a UIScrollView but have struggled to get it right for zooming into a single UITableViewCell.
At the bottom I have included the code that has worked for me for the UIScrollView. The challenge starts with what to return for the viewForZoomingInScrollView. If I try to give this method the UIImageView from the cell It throws an errors as it appears the viewForZoomingInScrollView is called before the table is loaded thus it can not find the cell I am referencing. If I pass the entire view itself self.view I can scroll but the entire tableview is zoomed (where I would like to zoom just the UIImageView inside the cell) and when I release the zoom I get an error Terminating app due to uncaught exception 'CALayerInvalidGeometry', reason: 'CALayer bounds contains NaN: [nan nan; 375 667] which is clearly not the correct path to take.
Any help or guidance here would be appreciated.
- (UIView*)viewForZoomingInScrollView:(UIScrollView *)scrollView {
return self.imageView;
}
- (void)scrollViewDidZoom:(UIScrollView *)scrollView {
[self centerScrollViewContents];
}
- (void)centerScrollViewContents {
CGSize boundsSize = zoomTable.bounds.size;
CGRect contentsFrame = self.imageView.frame;
if (contentsFrame.size.width < boundsSize.width) {
contentsFrame.origin.x = (boundsSize.width - contentsFrame.size.width) / 2.0f;
} else {
contentsFrame.origin.x = 0.0f;
}
if (contentsFrame.size.height < boundsSize.height) {
contentsFrame.origin.y = (boundsSize.height - contentsFrame.size.height) / 2.0f;
} else {
contentsFrame.origin.y = 0.0f;
}
self.imageView.frame = contentsFrame;
}
It sounds to me as though you want something like what Facebook or Twitter have, where you tap on an image and it zooms to fit the screen.
What you need to do is to consider that as a navigational step -- i.e. conceptually similar to what happens if you select a row in a standard table view and it pushes a new view controller onto the navigation controller stack, except that you probably want to present modally using a custom transition.
In the simple case, this would mean adding a tap gesture recogniser to the cell's image view; for the full effect you would add a pinch gesture recogniser to make an interactive transition.
I'd recommend watching the following WWDC videos:
2013 Session 218 "Custom Transitions Using View Controllers"
2014 Session 214 "View Controller Advancements in iOS 8"
2014 Session 228 "A Look Inside Presentation Controllers"
From your question What I understand is that you wanted to implement the functionality of Zoom in and Zoom out for ImageView. You first implemented that in a sample where you had a ScrollView Inside a ViewController and then ImageView inside that ScrollView. Things worked for you as expected. But then when you wanted the same functionality inside the TableViewCell, things didn't work for you.
So, I am suggesting you to use a View inside ScrollView as a ZoomView, and that ZoomView should have the ImageView as subview. And return that ZoomView in the method:
- (UIView*)viewForZoomingInScrollView:(UIScrollView *)scrollView { return self.ZoomView; }
No matter what, it seems that my NSScrollViews always appear on top of any other view, even if the other view has been added more recently and should appear on top.
What can I do to get another view (say just a plain NSView) to appear above an NSScrollView?
I finally solved this by setting setWantsLayer to YES (true in this case since I'm using RubyMotion) on the NSScrollView, the NSScrollView's content view and the external view that I want to appear above the NSScrollView.
That solved my problem and allowed other views to appear above the NSScrollView.
So check your xib, and make sure your scrollview is at the topmost of your view hierarchy ("Document Outline"). However, when loaded this doesn't necessarily 100% guarantee that the scrollview will be drawn first. A way to manually force the order you'd like for your views is to programmatically move them around based off tags.
In Interface Builder, in the Attributes Inspector, go to the bottom and find the "View" section. Add a tag to the view, with 0 being the bottom most view you'd like, and going up from there.
Then in your controller, add this method definition & a call to it:
NSComparisonResult compareViews(id firstView, id secondView, void *context) {
NSInteger firstTag = [firstView tag];
NSInteger secondTag = [secondView tag];
if (firstTag == secondTag) {
return NSOrderedSame;
} else {
if (firstTag < secondTag) {
return NSOrderedAscending;
} else {
return NSOrderedDescending;
}
}
}
[self.view sortSubviewsUsingFunction:(NSComparisonResult (*)(id, id, void*))compareViews context:nil];
This will ensure that you have your views in the correct order you'd like
I have an NSMenu popping out of an NSStatusItem using popUpStatusItemMenu. These NSMenuItems show a bunch of different links, and each one is connected with setAction: to the openLink: method of a target. This arrangement has been working fine for a long time. The user chooses a link from the menu and the openLink: method then deals with it.
Unfortunately, I recently decided to experiment with using NSMenuItem's setView: method to provide a nicer/slicker interface. Basically, I just stopped setting the title, created the NSMenuItem, and then used setView: to display a custom view. This works perfectly, the menu items look great and my custom view is displayed.
However, when the user chooses a menu item and releases the mouse, the action no longer works (i.e., openLink: isn't called). If I just simply comment out the setView: call, then the actions work again (of course, the menu items are blank, but the action is executed properly). My first question, then, is why setting a view breaks the NSMenuItem's action.
No problem, I thought, I'll fix it by detecting the mouseUp event in my custom view and calling my action method from there. I added this method to my custom view:
- (void)mouseUp:(NSEvent *)theEvent {
NSLog(#"in mouseUp");
}
No dice! This method is never called.
I can set tracking rects and receive mouseEntered: events, though. I put a few tests in my mouseEntered routine, as follows:
if ([[self window] ignoresMouseEvents]) { NSLog(#"ignoring mouse events"); }
else { NSLog(#"not ignoring mouse events"); }
if ([[self window] canBecomeKeyWindow]) { dNSLog((#"canBecomeKeyWindow")); }
else { NSLog(#"not canBecomeKeyWindow"); }
if ([[self window] isKeyWindow]) { dNSLog((#"isKeyWindow")); }
else { NSLog(#"not isKeyWindow"); }
And got the following responses:
not ignoring mouse events
canBecomeKeyWindow
not isKeyWindow
Is this the problem? "not isKeyWindow"? Presumably this isn't good because Apple's docs say "If the user clicks a view that isn’t in the key window, by default the window is brought forward and made key, but the mouse event is not dispatched." But there must be a way do detect these events. HOW?
Adding:
[[self window] makeKeyWindow];
has no effect, despite the fact that canBecomeKeyWindow is YES.
Add this method to your custom NSView and it will work fine with mouse events
- (void)mouseUp:(NSEvent*) event {
NSMenuItem* mitem = [self enclosingMenuItem];
NSMenu* m = [mitem menu];
[m cancelTracking];
[m performActionForItemAtIndex: [m indexOfItem: mitem]];
}
But i'm having problems with keyhandling, if you solved this problem maybe you can go to my question and help me a little bit.
Add this to your custom view and you should be fine:
- (BOOL)acceptsFirstMouse:(NSEvent *)theEvent
{
return YES;
}
I added this method to my custom view, and now everything works beautifully:
- (void)viewDidMoveToWindow {
[[self window] becomeKeyWindow];
}
Hope this helps!
I've updated this version for SwiftUI Swift 5.3:
final class HostingView<Content: View>: NSHostingView<Content> {
override func viewDidMoveToWindow() {
window?.becomeKey()
}
}
And then use like so:
let item = NSMenuItem()
let contentView = ContentView()
item.view = HostingView(rootView: contentView)
let menu = NSMenu()
menu.items = [item]
So far, the only way to achieve the goal, is to register a tracking area manually in updateTrackingAreas - that is thankfully called, like this:
override func updateTrackingAreas() {
let trackingArea = NSTrackingArea(rect: bounds, options: [.enabledDuringMouseDrag, .mouseEnteredAndExited, .activeInActiveApp], owner: self, userInfo: nil)
addTrackingArea(trackingArea)
}
Recently I needed to show a Custom view for a NSStatusItem, show a regular NSMenu when clicking on it and supporting drag and drop operations on the Status icon.
I solved my problem using, mainly, three different sources that can be found in this question.
Hope it helps other people.
See the sample code from Apple named CustomMenus
In there you'll find a good example in the ImagePickerMenuItemView class.
It's not simple or trivial to make a view in a menu act like a normal NSMenuItem.
There are some real decisions and coding to do.