I have an existing .xib that needs to be displayed as the main page in a Xamarin.Mac application. If I set the "Main Interface" as this existing .xib, it does display but it's not done by the time my DidFinishLaunching override gets called. This is where I expect to do some initialization, but the outlets I specified are all null.
I am new to Xamarin and I'm trying to figure out if I need to override a different call that lets me know that the main page is done loading or if the issue lies elsewhere.
I did see that an NSWindowController has a WindowDidLoad override, but if I set the Main Interface in the info.plist, how does it know what the ViewController is for that view so that my override WindowDidLoad gets called?
I'm thinking I probably need to create the main window manually in DidFinishLaunching, but I can't find any documentation on how to create the main window through an .xib. There is documentation on how to get a storyboard from a nib, but I am not seeing anything on loading a .xib. If someone can find a good reference on how the main window gets initialize (with all the plumbing included) in a Xamarin.Mac application, that may be enough.
Thank you in advance for your time.
The chain of events is roughly:
Main invokes NSApplication.Main
Reads Info.plist to determine what xib/storyboard to load.
Storyboard is loaded and inflated. The view controller has a custom class that points to "ViewController"
Your ViewController is spun up, and WindowDidLoad get called.
DidFinishLaunching is not exactly what you are looking for.
May I suggest take a look at the documentation in question to get a better understand of the full process:
https://developer.xamarin.com/guides/mac/getting_started/hello,_mac/#Anatomy_of_a_Xamarin.Mac_Application
Related
I would like to know what the established procedure is for initializing the controls within a Qt custom dialog box. In the code I am writing, the dialog would present a QListView containing directories from an object passed (by reference) to the dialog class during construction. When the dialog is displayed, I obviously want the list to display the directories currently configured in the object.
Where should this be done though? Perhaps in the overridden showEvent() method?
Background: I used to do a lot of MFC programming back in the day, and would have done this sort of stuff in the OnCreate method, or some such, once the window object had been created.
Thankfully Qt doesn't require you to do any hooking to find the moment to create things (unless you want to). If you look over the Qt examples for dialogs, most do all the constructing in the constructor:
http://doc.qt.io/archives/qt-4.7/examples-dialogs.html
The tab dialog example--for instance--doesn't do "on-demand" initializing of tabs. Although you could wire something up via the currentChanged signal:
http://doc.qt.io/archives/qt-4.7/qtabwidget.html#currentChanged
Wizard-style dialogs have initializePage and cleanupPage methods:
http://doc.qt.io/archives/qt-4.7/qwizardpage.html#initializePage
http://doc.qt.io/archives/qt-4.7/qwizardpage.html#cleanupPage
But by and large, you can just use the constructor. I guess the main exception would be if find yourself allocating the dialog at a much earlier time from when you actually display it (via exec), and you don't want to bear the performance burden for some part of that until it's actually shown. Such cases should be rare and probably the easiest thing to do is just add your own function that you call (like finalizeCreationBeforeExec).
ok so I have a TitleWindow that I open up... and I have 6 states defined. I am using the Presentation model pattern for all of my views. I have discovered a frustrating nuance. When I tell my window to go to XXX state, the controls have to initialize since the states in flex use lazy loading. so... my PM code that says myTextArea.text bombs out and say "cannot access..." so as a work around, I made some creationComplete events on my controls to register the control with the PM. So when the state changes, the textarea finally initializes and on creationComplete calls PM.registerTextArea() which sets a reference to it. then in that function I run my code... myTextArea.text.. etc.
This seems like such a ugly hack that I hate it. Is there any way to wait until the entire state in created then call code on the PM? I have tried enterstate... but this event seems to fire before the state controls are ready.
I tried to add a comment, but I guess editing is the only way I can do this...
to everyone: thanks for the great feedback. I am doing something slightly off straight PM. Every view has a viewController (as I call them). Its kinda my own hybrid of a delegate / dataprovider. But this is moot. It's the flex component lifecycle when dealing with states that is the pain. if you change state.. there is no event to say "all my components in this state are ready". only event to say "we changed state". so my code that fires on state change is trying to talk to components that aren't ready yet. So from what I see, there seems to be no design pattern or perfect way to ensure that all components are created in a state unless using creationComplete on every component in the state to register it is ready... if you don't, you get a race condition. Regardless of frameworks or design patterns, this seems to be a root issue.
The textarea is an easy PM fix.. just bind it to the pm value. But there are other times I can't.
Specifically, I am trying to attach video to a display once I get to that state. This is done via addchild. regardless of where I do it.. I need to know that the videoDisplay is done loading before I call addchild. I even tried currentStateChange event since docs say that fires last... but alas.. the components in the state are still initializing. So it seems that creationComplete is my only option. Maybe the only sane way to keep to clean code is to create the entire thing (videodisplay and video) using as once the state is entered. I just hoped the flex framework had events to ehlp me here rather than buiilding everything on the fly in as.
Since your PM has a reference to a visual component (myTextArea), this isn't a completely pure form of a presentation model. It appears to be more of a supervising presenter / controller type of setup.
That being said, the way I would fix your problem would be to use a complete presenter outright ( no knowlege of the view at all ) or use a complete controller ( view implements an interface through which the controller communicates ). The advantage of using a presenter in Flex is that you can create a bindable value such as text or selectedItem, and the view will bind to that variable whenever it comes online so the issues dealing with the lifecycle of Flex components go away.
I would like to know the correct way to close an AIR application programmatically.
In my Spark WindowedApplication I have:
this.addEventListener( Event.CLOSING, shutdownApp );
and of course an implementation of the shutdownApp method (which basically tidies up temporary files).
This works fine for the top-right close button of the window. However I also have functionality which needs to shutdown the application. Within the code I have called:
NativeApplication.nativeApplication.exit();
However this doesn't trigger the Event.CLOSING method, and so my temporary files are not cleared up. Should I not be calling nativeApplication.exit ? If so, what should I call instead? I'd rather not have to call my shutdownApp method before the NativeApplication.exit() as this doesn't feel quite so elegant.
Can anyone shed any light on the correct way of doing this?
Thanks,
Phil
I know this question has been answered and accepted, but thought I'd share, I use.
stage.nativeWindow.close();
The documentation looks a bit ambiguous on this and I would have the same interpretation that you did. Did you try the close or exit methods on the WindowedApplication?
Something like this, with FlexGlobals and topLevelApplication:
(FlexGlobals.topLevelApplication as WindowedApplication).close();
or
(FlexGlobals.topLevelApplication as WindowedApplication).exit();
Just give an answer here because I searched for a related question and was not able to find sth.
I wanted to do something similar and close an AIR application when the native close button of the document window (spark.components.Window) is pressed thought that the spark WindowedApplication container (the applications main window) is still active to hold and manage the native menu (at application startup it is also used to display a splash screen. It has to stay open since if it is closed the native menu won't show up or be accessible anymore so its visible property is just set to false).
My main problem was the window closing event. Registering it with ActionScript like
this.addEventListener(Event.Closing, windowClosed);
does not work: No closing event was dispatched.
The only way was to register an event handler directly in the s:Window element at start of the MXML file. I just throw in the closing attribute:
closing="window1_closingHandler(event)"
The event was dispatched then and in window1_closingHandler-function I called
NativeApplication.nativeApplication.exit();
That works for me and shuts down the whole application.
this is a very basic question but I could not figure out.
My flex application gets some parameters from URL when the application opens for the first time(ex: layout=<1,2,3,4> ). Based on layout(1,2,3,4) value I have to change the layout. However the problem is the application is already drawn(Layout is initialized) by the time the control reaches the point where it reads the values from the URL.
I was wondering how can I redraw once I read the values from URL. Some thing like refresh.
Or is there a better approach to my problem.
thank you
I am not sure if this is the right approach but I fixed my problem my calling the function which is responsible for layout in applicationComplete.
It works great now.
The better approach would be to wait for the URL to be parsed and then create your view based on that value.
This means that your Main.mxml should be empty when the application loads and when you parse the URL add your MainView to the application.
Something like
- CreationComplete
- ParseURL
- AddMainViewElement
According to the adobe documentation:
"After all components are created and drawn, the Application object dispatches an applicationComplete event. This is the last event dispatched during an application startup."
( http://help.adobe.com/en_US/flex/using/WS2db454920e96a9e51e63e3d11c0bf69084-7ee6.html)
so "applicationComplete" event fired after all the components created.
I am naive to Qt and GUI programming.
Qt jpg image display
The procedure given for displaying an image is working fine and thank you for providing that. But I want to display an image when I click on radiobutton.
I created a slot, and I connected the button click event to the slot (dispImage is my slot). My slot consists only the code which is working to display an image (First answer in this link).
I am able to compile it and run it. But the o/p is not as we desire.
On button click, image window flashes for a sec and disappears.
One more point to share is, I tried the same with windowsflags example present in qt examples.
In this example I want to display the image on the preview window created by us. Even this is also not worked for me.
Please provide me the solution.
Thanks in advance.
This is happening because the method that you're connecting to the slot is creating all of the objects needed to display the image on the stack and they're going out of scope and being destroyed when that method returns. The linked example has the event loop running at the end of the method, so the objects don't go out of scope until the program exits.
You can fix this by making the necessary objects member variables of a class that has application lifetime.
Stu's answer above is correct.
If you don't understand what he's talking about, you may want to get a little bit more familiar with C++ before jumping into Qt. The example you are citing is different from what you are trying to do. It's a main() function whose stack variables aren't going to go out of scope until the process exits (that's when main() returns). The stack variables in a method go out of scope as soon as the method returns.
Using the example you cite as a template for your method, you need to declare the QGraphicsView object as a class variable in the header file for your radioslot object. This will make it so it stays in scope until your radioslot object is destroyed.