I have a for loop editing an array of model objects, some of which require user input and some of which do not. I would like to be able to open a second window as needed to display multiple choices to the user, receive the user's selection, close the second window, and then return to the place I was in the original loop. In AppleScript, this could be done simply with a "choose from list" dialog. But I haven't figured out how to do it in Cocoa since the NSNotificationCenter architecture requires me to process the second window's response in a different selector. Thus the loop is broken and I can't process the rest of the array. I also tried doing it with delegation to no avail. Are panels and alerts the only way to do this?
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I have a Cocoa app that presents a folder structure to the user and allows basic file system operations such as move/copy/rename.
I perform all file system access on a background queue and use file coordination via NSFileCoordinator.
Let's imagine the user drags the file "Notes.txt" into the folder "Project B". Here is what I do:
I schedule the file operation of moving the file on the background queue.
Once that's done, it calls a block on the main queue where I update the outline view
Let's assume the background operation moving the file takes some time. I need to prevent that the user continues to move files around or performs other actions until the first operation completes.
Hence I would like to:
Disable all user interaction with the window
Disable most menu items and keyboard shortcuts
Keep certain menus such as [Quit Cmd-Q] working
Don't block the main thread
One solution that comes to mind: use a modal sheet?.
I don't want to do this, because most of the time, the operation will finish quickly and the sheet would only be shown for a fraction of a second, which is distracting.
I keep track of how long the operation takes would switch from "interaction blocked mode" to "modal sheet" if it takes more than 500 ms.
The question is: how can I implement such a "user interaction blocked mode" without actually presenting a modal sheet?
Alternative idea: disabling all controls
I considered setting isEnabled = false for all controls, but that's not an option, because the UI can be arbitrarily complex and it won't prevent actions via the menu or keyboard shortcuts.
You may find helpful The Responder Chain article in Apple's Documentation. Proper solution depends on what you exactly need. Overriding NSMenu's - (BOOL)validateMenuItem:(NSMenuItem *)menuItem; let you control over enable menu items and its shortcuts. You may also put transparent NSView over the area you want to prevent from user's interactions.
I'm working on a custom cross platform UI library that needs a synchronous "ShowPopup" method that shows a popup, runs an event loop until it's finished and automatically cancels when clicking outside the popup or pressing escape. Keyboard, mouse and scroll wheel events need to be dispatched to the popup but other events (paint, draw, timers etc...) need to be dispatched to their regular targets while the loop runs.
Edit: for clarification, by popup, I mean this kind of menu style popup window, not an alert/dialog etc...
On Windows I've implemented this fairly simply by calling GetMessage/DispatchMessage and filtering and dispatching messages as appropriate. Works fine.
I've much less experience with Cocoa/OS X however and finding the whole event loop/dispatch paradigm a bit confusing. I've seen the following article which explains how to implement a mouse tracking loop which is very similar to what I need:
http://stpeterandpaul.ca/tiger/documentation/Cocoa/Conceptual/EventOverview/HandlingMouseEvents/chapter_5_section_4.html
but... there's some things about this that concern me.
The linked article states: "the application’s main thread is unable to process any other requests during an event-tracking loop and timers might not fire". Might not? Why not, when not, how to make sure they do?
The docs for nextEventMatchingMask:untilDate:inMode:dequeue: states "events that do not match one of the specified event types are left in the queue.". That seems a little odd. Does this mean that if an event loop only asks for mouse events then any pressed keys will be processed once the loop finishes? That'd be weird.
Is it possible to peek at a message in the event queue without removing it. eg: the Windows version of my library uses this to close the popup when it's clicked outside, but leaves the click event in the queue so that clicking outside the popup on a another button doesn't require a second click.
I've read and re-read about run loop modes but still don't really get it. A good explanation of what these are for would be great.
Are there any other good examples of implementing an event loop for a popup. Even better would be pseudo-code for what the built in NSApplication run loop does.
Another way of putting all this... what's the Cocoa equivalent of Windows' PeekMessage(..., PM_REMOVE), PeekMessage(..., PM_NOREMOVE) and DispatchMessage().
Any help greatly appreciated.
What exactly is a "popup" as you're using the term? That term means different things in different GUI APIs. Is it just a modal dialog window?
Update for edits to question:
It seems you just want to implement a custom menu. Apple provides a sample project, CustomMenus, which illustrates that technique. It's a companion to one of the WWDC 2010 session videos, Session 145, "Key Event Handling in Cocoa Applications".
Depending on exactly what you need to achieve, you might want to use an NSAlert. Alternatively, you can use a custom window and just run it modally using the -runModalForWindow: method of NSApplication.
To meet your requirement of ending the modal session when the user clicks outside of the window, you could use a local event monitor. There's even an example of just such functionality in the (modern, current) Cocoa Event Handling Guide: Monitoring Events.
All of that said, here are (hopefully no longer relevant) answers to your specific questions:
The linked article states: "the application’s main thread is unable to process any other requests during an event-tracking loop and
timers might not fire". Might not? Why not, when not, how to make
sure they do?
Because timers are scheduled in a particular run loop mode or set of modes. See the answer to question 4, below. You would typically use the event-tracking mode when running an event-tracking loop, so timers which are not scheduled in that mode will not run.
You could use the default mode for your event-tracking loop, but it really isn't a good idea. It might cause unexpected re-entrancy.
Assuming your pop-up is similar to a modal window, you should probably use NSModalPanelRunLoopMode.
The docs for nextEventMatchingMask:untilDate:inMode:dequeue:
states "events that do not match one of the specified event types are
left in the queue.". That seems a little odd. Does this mean that if
an event loop only asks for mouse events then any pressed keys will be
processed once the loop finishes? That'd be weird.
Yes, that's what it means. It's up to you to prevent that weird outcome. If you were to read a version of the Cocoa Event Handling Guide from this decade, you'd find there's a section on how to deal with this. ;-P
Is it possible to peek at a message in the event queue without removing it. eg: the Windows version of my library uses this to close
the popup when it's clicked outside, but leaves the click event in the
queue so that clicking outside the popup on a another button doesn't
require a second click.
Yes. Did you notice the "dequeue:" parameter of nextEventMatchingMask:untilDate:inMode:dequeue:? If you pass NO for that, then the event is left in the queue.
I've read and re-read about run loop modes but still don't really get it. A good explanation of what these are for would be great.
It's hard to know what to tell you without knowing what you're confused about and how the Apple guide failed you.
Are you familiar with handling multiple asynchronous communication channels using a loop around select(), poll(), epoll(), or kevent()? It's kind of like that, but a bit more automated. Not only do you build a data structure which lists the input sources you want to monitor and what specific events on those input sources you're interested in, but each input source also has a callback associated with it. Running the run loop is like calling one of the above functions to wait for input but also, when input arrives, calling the callback associated with the source to handle that input. You can run a single turn of that loop, run it until a specific time, or even run it indefinitely.
With run loops, the input sources can be organized into sets. The sets are called "modes" and identified by name (i.e. a string). When you run a run loop, you specify which set of input sources it should monitor by specifying which mode it should run in. The other input sources are still known to the run loop, but just ignored temporarily.
The -nextEventMatchingMask:untilDate:inMode:dequeue: method is, more or less, running the thread's run loop internally. In addition to whatever input sources were already present in the run loop, it temporarily adds an input source to monitor events from the windowing system, including mouse and key events.
Are there any other good examples of implementing an event loop for a popup. Even better would be pseudo-code for what the built in
NSApplication run loop does.
There's old Apple sample code, which is actually their implementation of GLUT. It provides a subclass of NSApplication and overrides the -run method. When you strip away some stuff that's only relevant for application start-up or GLUT, it's pretty simple. It's just a loop around -nextEventMatchingMask:... and -sendEvent:.
I have a windows application which has several sub-forms. i have to navigate through 5 or 6 forms to reach the form i need. this is time consuming since i have to open it several times through the day and i do it daily.
my need: i dont have the source project for this application, i got it as an executable program, but i need to create some application that does these steps for me automatically. In other words i need to find a way to automatically click the buttons that navigate through the forms and opens the form i need from step one.
is there any way i can do this ?
There is indeed, though generic solutions already exist to perform just this kind of function to arbitrary programs.
You can use Spy++ or a resource-editor, like ResHack or ResEdit to look at the program and get the control ids of the navigation buttons.
Once done, you can get a handle to the program itself and then send messages to it's WindowProcedure that would be generated if the user clicked the controls with a mouse,
Another alternative, is to get the position of the running target application, after you've got it's HWND, by using the GetWindowRect function. You could then use this position along with vert/horiz distances to generate mouse events.
The two have more-or-less the same result, though some applications won't work with approach #1.
In one instance, you need to use Spy++ to get the control IDs.
In the other instance, you need to use an image editor to get the pixel offsets of the controls.
In both instances, you'll need to use FindWindow, along with the window's title-text in order to get a HWND handle.
You could use a combination of the two - asking the program itself with GetDlgItem for the handle of the controls you need to click. You could then query the control for its position, before using mouse_event to position the mouse above it and again to click it.
Quite a few ways to skin this cat, actually.
Pre-existing solutions like AutoIt are said to be very easy to use and will be much easier than coding a new program for each target.
I'm working on a applescript to update the content of a document in Microsoft Word. The updating process is quite long (might take more than 5s). So I want to prevent users to change anything during the updating. Do you know whether Microsoft or Applescript a function like that?
In Windows, I can just display a User Form (which is a dialog telling that "we are updating... ") and close that form when it's done. However, I don't know whether I can do the same in Mac (with Applescript alone).
When you say "applescript", I don't know if you mean "plain" applescript or the AppleScriptObjC version. If you mean the latter, then I know ways to do it.
One way I've used during slow processes is to put an overlay view over the whole content view of the window. I make it translucent white to partially obscure the window, and put some kind of message (and maybe a progress indicator) on it. You can just use an NSBox (of the custom type) in IB to make this, and then make a subclass of NSBox to color the view and override mouseDown:. MouseDown:, doesn't need to have any code in it, just by overriding it, you capture any key and mouse events so they don't accumulate on the event queue, and get used by the view below after your overlay goes away. Here's code I've used:
script Overlay
property parent : class "NSBox"
on awakeFromNib()
set overlayColor to current application's NSColor's colorWithCalibratedWhite_alpha_(1,.8)
setFillColor_(overlayColor)
end
on mouseDown_(theEvent)
--log "mouseDown"
end
end script
I have this view as the top most view in the view hierarchy, and set its hidden property to true until I want to show it.
Is it possible to create a dialog ressource with a resource editor and then put this dialog (possibly multiple times) into another dialog?
Here's some background. I need to create a C++ program (Windows). The user needs to input a set of similar data on a dialog. Say, for simplicity's sake, an element of this data-set consist of an edit control and a scrollbar. Since this combination (edit + scrollbar) needs to be put onto the dialog for each element for the data-set, I thought I could create a simple dialog with just one edit control and one scrollbar, and then put this dialog mutliple times onto its "parent" dialog.
So, is this possible at all. Any pointers will be greatly appreciated.
Yes, you can do this.
In the dialog editor, set the "Control Parent" flag on the parent dialog. (This will ensure the tab key works to cycle through items in the child dialogs as if they were part of the parent dialog.)
Make sure the child dialog(s) have the "Child" flag set in the dialog editor. Visually, they'll look like dialogs without any border at all in the editor.
At runtime, create the child dialogs as children of the parent dialog using CreateDialog (or CreateDialogParam, etc.). When calling CreateDialog you specify the dialogproc for each window.
I often make the child dialog procs do little more than forward messages to the main window's dialog proc (calling it directly; not via SendMessage), but you have to be careful, obviously. You have to be especially careful if you are creating multiple copies of the same dialog in a single parent, since obviously the control IDs within that dialog will all be the same and you need to differentiate them (perhaps by the parent's hWnd).
You don't have to forward messages to the parent, though. I just do usually do that so that most of the dialog's logic is in one place instead of spread out.
EDIT: Corrected statements about creating the child dialogs, window classes etc. I was mixing up dialogs and normal windows, making things more complex than they are in this case. Sorry about that!