I'm new to Mac programming and I want to fire events when the cursor enters or exits the main window. I read something about NSTrackingArea but I don't understand exactly what to do.
Apple provides documentation and examples for NSTrackingAreas.
The easiest way to track when a mouse enters or exits a window is by setting a tracking area in the window's contentView. This will however not track the window's toolbar
Just as a quick example, in the custom content view's code:
- (void) viewWillMoveToWindow:(NSWindow *)newWindow {
// Setup a new tracking area when the view is added to the window.
NSTrackingArea* trackingArea = [[NSTrackingArea alloc] initWithRect:[self bounds] options: (NSTrackingMouseEnteredAndExited | NSTrackingActiveAlways) owner:self userInfo:nil];
[self addTrackingArea:trackingArea];
}
- (void) mouseEntered:(NSEvent*)theEvent {
// Mouse entered tracking area.
}
- (void) mouseExited:(NSEvent*)theEvent {
// Mouse exited tracking area.
}
You should also implement NSView's updateTrackingAreas method and test the event's tracking area to make sure it is the right one.
Answer by Matt Bierner really helped me out; needing to implement -viewWillMoveToWindow: method.
I would also add that you will also need to implement this if you want to handle tracking areas when the view is resized:
- (void)updateTrackingAreas
{
// remove out-of-date tracking areas and add recomputed ones..
}
in the custom sub-class, to handle the view's changing geometry; this'll be invoked for you automatically.
Related
This is for a Mac app written with Cocoa and Objective-C.
I have a custom NSView class that essentially works as a collection of buttons and stores the value of the selected button. Sort of like an NSSlider that snaps to the tick marks but with buttons instead of a slider. The image below on the left is what it looks like.
Now what I want to do is make it so that when the mouse moves over each button, it covers that button with a semi-transparent blue color that then stays there when it is clicked. I've made a few attempts and you can see the latest result in the image on the right:
This is what happens after mousing over all the buttons. For some reason it draws using the window's origin instead of drawing inside the MyButtonView. Also, it is not semi-transparent. I haven't yet worried about redrawing the normal button when the mouse leaves the rectangle since this part isn't working yet anyway.
Now here's the pertinent code.
Inside the initWithFrame method of the MyButtonView class:
for (int i = 0; i < 12; i++) {
yOrigin = kBorderSize + (buttonHeight * i) + (kSeparatorSize * i);
NSRect newRect = { {xOrigin, yOrigin}, {buttonWidth, buttonHeight} };
[buttonRectangles addObject:NSStringFromRect(newRect)];
[self addTrackingRect:newRect owner:self userData:NULL assumeInside:NO];
}
The methods that draw the blue rectangles:
- (void)mouseEntered:(NSEvent *)theEvent {
NSRect rect = [[theEvent trackingArea] rect];
[self drawHoverRect:rect withColor:hoverBlue];
}
- (void)drawHoverRect:(NSRect)rect withColor:(NSColor *)color {
[color set];
NSRectFill(rect);
[self displayRect:rect];
}
I have no idea how to do this. I've been poring over Apple's documentation for a few hours and can't figure it out. Obviously though, I'm no veteran to Cocoa or Objective-C so I would love some help.
One fundamental problem you have is that you are bypassing the normal drawing mechanisms and trying to force the drawing yourself. This is a common mistake for first timers. Before you go any further, you should read Apple's View Programming Guide:
https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/CocoaViewsGuide/Introduction/Introduction.html#//apple_ref/doc/uid/TP40002978
If you have trouble with that, then you might need to back up and start with some of the more fundamental Objective-C/Cocoa guides and documentation.
Back to your actual view, one thing that you are going to have to do in this view is do all your drawing in the drawRect: method. You should be tracking the state of your mouse movements via some kind of data structure and then drawing according to that data structure in your drawRect: method. You will call
[self setNeedsDisplay:YES];
in your mouse tracking method(s), after you've recorded whatever change has occurred in your data structure. If you only want to ever draw one button highlighted at a time, then your data structure could be as simple as an NSInteger whose value you set to the index of your selected button (or -1 or whatever to indicate no selection).
For the sake of learning, the reason your blue boxes are currently drawing from the window's origin is that you are calling drawing code outside of the "context" that's normally setup for your view when drawRect: is called by the system. That "context" would include a translation to move the current origin to the origin of your view, rather than the origin of the window.
I'm very new with iOS Development and I have just created one of my first apps, in my .xib file I have a UINavigationBar that I want to hide/show when a part of the screen is tapped by the user (like in the Photo app). I've found some snippets online but I don't know where and how to use those.
I'd appreciate a lot if somebody could give me detailed informations about how to do this.
Add this toggle method anywhere in your UIViewController. This hides on first tap and shows again in second tap.
- (void)toggleNavBar:(UITapGestureRecognizer *)gesture {
BOOL barsHidden = self.navigationController.navigationBar.hidden;
[self.navigationController setNavigationBarHidden:!barsHidden animated:YES];
}
If there is no navigation controller, link the navigation bar with an IBOutlet and replace with
- (void)toggleNavBar:(UITapGestureRecognizer *)gesture {
BOOL barsHidden = self.navBar.hidden;
self.navBar.hidden = !barsHidden;
}
Then add the following in the method -(void)viewDidLoad {}
UITapGestureRecognizer *gesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(toggleNavBar:)];
[self.view addGestureRecognizer:gesture];
[gesture release];
If the view where you are going to tap is a UIWebViewController, you have to add the protocol to the view controller and set it as delegate gesture.delegate = self; then add the following:
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer
shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
return YES;
}
This is needed because the UIWebViewController already implements its own gesture recognizers.
Ultimately, you want to send the -setHidden: message to your navigation bar. The easiest way to do this is to make an Outlet and an Action in your in your view controller. Then, in your .xib file, connect the navigation bar to the outlet and some button (even a large, full screen one) to the action.
Outlets and Actions are basic techniques used over and over in iOS
(and Mac) programming, so if you don't understand them, best go read
up on them now. Every beginning iOS/Mac programming book covers this
topic as does Apple's own Getting Started guide (pay particular
attention to the Configuring the View section).
Inside your action, send a message to the outlet like so:
-(void)myButtonAction:(id)sender{
[[self myNavigationBarOutlet] setHidden:YES];
}
This will hide the navigation bar whenever your button is tapped.
(This assumes you have a UINavigationBar in your .xib like you say. These directions will be different if you're working with a UINavigationController that manages its own UINavigationBar)
I'm trying to trigger basic functions using NSEvent and mouse clicks. For example close the window when pressing left mouse button. What else do I need in this method?
Thanks.
- (void)mouseDown:(NSEvent *)theEvent {
if ([theEvent type] == NSLeftMouseDown){
[window orderOut:nil];
}
}
Assuming this is in a custom view and the window outlet is connected (or you fill in that variable with [self window] when the view is added to a superview), that should be all you need. I would suggest handling mouseUp: instead of mouseDown:, though, to give the user the opportunity to back out by moving the mouse outside of your view.
You might also consider using an NSButton instead of (or inside of) a custom view. You could hook it up directly to the window's performClose: or orderOut: action.
in my cocoa application, I need a custom NSCell for an NSTableView. This NSCell subclass contains a custom NSButtonCell for handling a click (and two or three NSTextFieldCells for textual contents). You'll find a simplified example of my code below.
#implementation TheCustomCell
- (void)drawWithFrame:(NSRect)cellFrame inView:(NSView *)controlView {
// various NSTextFieldCells
NSTextFieldCell *titleCell = [[NSTextFieldCell alloc] init];
....
// my custom NSButtonCell
MyButtonCell *warningCell = [[MyButtonCell alloc] init];
[warningCell setTarget:self];
[warningCell setAction:#selector(testButton:)];
[warningCell drawWithFrame:buttonRect inView:controlView];
}
The problem I'm stuck with is: what is the best/right way to get that Button (more precisely: the NSButtonCell) inside this NSCell to work properly? "work" means: trigger the assigned action message and show the alternate image when clicked. Out of the box, the button doesn't do anything when clicked.
Information / readings on this topic is hard to find. The only posts I found on the net pointed me to implementing
- (BOOL)trackMouse:(NSEvent *)theEvent inRect:(NSRect)cellFrame ofView:(NSView *)controlView untilMouseUp:(BOOL)untilMouseUp;
Is this the correct way to do it??? Implement trackMouse: in my containing NSCell? And then forward the event to the NSButtonCell? I would have expected the NSButtonCell itself to know what to do when it's being clicked (and I saw the trackMouse: methods more in cunjunction with really tracking mouse movements - not as a training wheel for 'standard' click behaviour). But it seems like it doesn't do this when included in a cell itself...
It seems I haven't grasped the big picture on custom cells, yet ;-)
I'd be glad if someone could answer this (or point me to some tutorial or the like) out of his own experience - and tell me if I'm on the right track.
Thanks in advance,
Tobi
The minimal requirements are:
After left mouse down on the button, it must appear pressed whenever the mouse is over it.
If the mouse then releases over the button, your cell must send the appropriate action message.
To make the button look pressed, you need to update the button cell's highlighted property as appropriate. Changing the state alone will not accomplish this, but what you want is for the button to be highlighted if, and only if, its states is NSOnState.
To send the action message, you need to be aware of when the mouse is released, and then use -[NSApplication sendAction:to:from:] to send the message.
In order to be in position to send these messages, you will need to hook into the event tracking methods provided by NSCell. Notice that all those tracking methods, except the final, -stopTracking:... method, return a Boolean to answer the question, "Do you want to keep receiving tracking messages?"
The final twist is that, in order to be sent any tracking messages at all, you need to implement -hitTestForEvent:inRect:ofView: and return an appropriate bitmask of NSCellHit... values. Specifically, if the value returned doesn't have the NSCellHitTrackableArea value in it, you won't get any tracking messages!
So, at a high level, your implementation will look something like:
- (NSUInteger)hitTestForEvent:(NSEvent *)event
inRect:(NSRect)cellFrame
ofView:(NSView *)controlView {
NSUInteger hitType = [super hitTestForEvent:event inRect:cellFrame ofView:controlView];
NSPoint location = [event locationInWindow];
location = [controlView convertPointFromBase:location];
// get the button cell's |buttonRect|, then
if (NSMouseInRect(location, buttonRect, [controlView isFlipped])) {
// We are only sent tracking messages for trackable areas.
hitType |= NSCellHitTrackableArea;
}
return hitType;
}
+ (BOOL)prefersTrackingUntilMouseUp {
// you want a single, long tracking "session" from mouse down till up
return YES;
}
- (BOOL)startTrackingAt:(NSPoint)startPoint inView:(NSView *)controlView {
// use NSMouseInRect and [controlView isFlipped] to test whether |startPoint| is on the button
// if so, highlight the button
return YES; // keep tracking
}
- (BOOL)continueTracking:(NSPoint)lastPoint at:(NSPoint)currentPoint inView:(NSView *)controlView {
// if |currentPoint| is in the button, highlight it
// otherwise, unhighlight it
return YES; // keep on tracking
}
- (void)stopTracking:(NSPoint)lastPoint at:(NSPoint)stopPoint inView:(NSView *)controlView mouseIsUp:(BOOL)flag {
// if |flag| and mouse in button's rect, then
[[NSApplication sharedApplication] sendAction:self.action to:self.target from:controlView];
// and, finally,
[buttonCell setHighlighted:NO];
}
The point of NSCell subclasses is to separate responsibility for rendering and handling common UI elements (the controls) from the visual- and event-hierarchy
responsibilities of the NSView classes. This pairing permits each one to provide greater specialization and variability without burdening the other. Look at the large number of NSButton instances one can create in Cocoa. Imagine the number of NSButton sub-classes that would exist if this split in functionality were absent!
Using design pattern language to describe the roles: an NSControl acts as a façade, hiding details of its composition from its clients and passing events and rendering messages to its NSCell instance which acts as a delegate.
Because your NSCell subclass includes other NSCell subclass instances within its composition, they no longer directly receive these event messages from the NSControl instance which is in the view hierarchy. Thus, in order for these cell instances to receive event messages from the event responder chain (of the view hierarchy), your cell instance needs to pass along those relevant events. You are recreating the work of the NSView hierarchy.
This isn't necessarily a bad thing. By replicating the behavior of NSControl (and its NSView superclass) but in an NSCell form, you can filter the events passed on to your sub-cells by location, event type, or other criteria. The drawback is replicating the work of NSView/NSControl in building the filtering & management mechanism.
So in designing your interface, you need to consider whether the NSButtonCell (and NSTextFieldCells) are better off in NSControls in the normal view hierarchy, or as sub-cells in your NSCell subclass. It's better to leverage the functionality which already exists for you in a codebase than to re-invent it (and continue maintaining it later) unnecessarily.
Normal OSX applications eat the first mouse click when not focused to first focus the application. Then future clicks are processed by the application. iTunes play/pause button and Finder behave differently, the first click is acted on even when not focused. I am looking for a way to force an existing application (Remote Desktop Connection.app) to act on the first click and not just focus.
Check NSView's acceptsFirstMouse, it may be what you're looking for.
acceptsFirstMouse:
Overridden by subclasses to return YES if the receiver should be sent a mouseDown: message for an initial mouse-down event, NO if not.
(BOOL)acceptsFirstMouse:(NSEvent *)theEvent
Parameters
theEvent
The initial mouse-down event, which must be over the receiver in its window.
Discussion
The receiver can either return a value unconditionally or use the location of theEvent to determine whether or not it wants the event. The default implementation ignores theEvent and returns NO.
Override this method in a subclass to allow instances to respond to click-through. This allows the user to click on a view in an inactive window, activating the view with one click, instead of clicking first to make the window active and then clicking the view. Most view objects refuse a click-through attempt, so the event simply activates the window. Many control objects, however, such as instances of NSButton and NSSlider, do accept them, so the user can immediately manipulate the control without having to release the mouse button.
Responding to the first mouse click when not focused is called 'click through'. And its worth is debated heatedly, for instance here and here.
// Assuming you have 1 view controller that's always hanging around. Over ride the loadview. N.B. this won't work pre-yosemite.
- (void)loadView {
NSLog(#"loadView");
self.view = [[NSView alloc] initWithFrame:
[[app.window contentView] frame]];
[self.view setAutoresizingMask:NSViewWidthSizable | NSViewHeightSizable];
int opts = (NSTrackingMouseEnteredAndExited | NSTrackingActiveAlways);
trackingArea0 = [[NSTrackingArea alloc] initWithRect:self.view.bounds
options:opts
owner:self
userInfo:nil];
[self.view addTrackingArea:trackingArea0];
}
- (void)mouseEntered:(NSEvent *)theEvent {
NSLog(#"entered");
if ([[NSApplication sharedApplication] respondsToSelector:#selector(activateIgnoringOtherApps:)]) {
[[NSApplication sharedApplication] activateIgnoringOtherApps:YES];
}
}