Custom Collection View is not showing up - xamarin.ios

I'm working on an app that'll have a range of images and the collectionview is not showing up at all. I was following this article, which I translated to C#.
here is an example app I made to show a minimal example of what I'm trying to do.
When I run through the code, GetCell in the collection source isn't firing which I know is the problem, but I don't know why it's not firing and I'm simply at a lost on what I'm missing.

I test it again today and I can make sure that the problem is caused by the MosaicCollectionLayout.
What I did today is that I removed your collectionView and add a new collectionView, then I add Constrains to it with a fixed height and width(to make sure it appears even if there is no data), then I change the layout to FlowLayout, it works, here is the screenshot:
After that, I changed the layout back to MosaicCollectionLayout, I get an exception in the line _cachedAttributes.Reverse(lastIndex.Row, firstMatchIndex.Value); inside the method LayoutAttributesForElementsInRect.
I checked the article and did not find a solution yet. Maybe there is some mistakes in the codes translated from swift to C#. So the problem is not related to the xib, please check the code in the method LayoutAttributesForElementsInRect.You can also try add Constrains to your collectionView. Hope these information helps you.

Related

WKWebView migration issues

Further to my earlier question
Migrating iOS Hybrid App from UIWebView to WKWebview
I have made good progress and only have a few loose ends to tidy up. The overall performance improvement over UIWebView is outstanding.
In UIWebView it was possible to set the focus on a text field programatically using
webView.keyboardDisplayRequiresUserAction = NO ;
However this is not available in WKWebView and ever since 2016 programmers have been developing an updating work arounds (swizzles) to overcome this.
I have tried implementing the latest of these I could find on Stack Overflow, which I found at https://stackoverflow.com/a/55344531/5948260
However as I am very inexperienced at coding in XCode please could someone tell me exactly how I add the above solution to my project. I have tried in vain to find examples of how exactly to do this i
on GitHub or elsewhere but to no avail.
So far I have tried copying the code provided in the above answer into a .m file and adding it to my project, but I got 20 or so errors, I then added an import statement for Foundation and most of these went away but XCode complained that it did not know what class WebViewInjection is. Also must there be a corresponding header file?. Must there be a corresponding interface statement? How does the method defined in the answer get invoked?
As I could not answer any of these, I also tried adding the method into my ViewController class. Whilst this was accepted with no errors, it had no effect on my app, ie. the keyboard did not come up automatically.
I would also want the webview to resize to appear above the keyboard and not to scroll to where the text field is as this seems a very messy solution to me.
All help very gratefully received.
I have now managed to get the keyboard displayed by adding
[self allowDisplayingKeyboardWithoutUserAction];
to viewDidLoad
I kept the allowDisplayingKeyboardWithoutUserAction method declaration inside my ViewController but changed the + infront of the method declaration to a - and this seems to have worked.
I still do not know how to resize the webview when the keyboard is displayed.

Questions about Citymaps

1、I want to create a circle and set an image that customized to fill the circle,use this as a marker on the map, not only could change the image but also the color of circle anytime,what can I do to implements this function? Please look at the picture below!
2、Like your CityMaps app show,when I enlarge the map, some business icon that hide are show on the map,which are hide again while shrink the map, How to achieve this effect?
3、After I initialization the Object Marker and called the method marker.setFadeTime(3000),the software give my tips the method is no exist and I see the class Marker.java but really not find the method,Why is it so?
4、I want to add some stars beside the marker like this:
What can I do to add the stars?the label only can set the text beside the marker.
5、I want to load your maps at the fragment,not the activity that extends FragmentActivity,I found the SupportCitymapsMapFragment is no use,What I can do to complete this requirement?
6、In your apps,it is locate that place after input New York in the search box,What can i do to complete this function whatever i input?
7、During I develop the apps about the Citymaps,I found a serious problem so that your apps had happend too. When I run the apps, the program force flash back all of a sudden and I run your apps Citymaps at this time,the problems are same of the front,I found some error in logical view that is follows:15327-15374/com.map.maplbs A/libc﹕ Fatal signal 11 (SIGSEGV) at 0xdeadbaad (code=1), thread 15374 (Thread-1819).
To solve the problem,I must restart my device. Why is it so?
I am a developer on the Citymaps SDK, I will do my best to answer your questions.
1) I recommend using the Android Canvas API to construct the images, and then use a Marker to display it on the map. See the documentation for details: http://developer.citymaps.com/markers
2) This is built into the Citymaps BusinessLayer. This functionality is not exposed through an API. If you wish to use the Citymaps BusinessLayer, you should create a CitymapsMapView or CitymapsMapFragment/SupportCitymapsMapFragment and it will automatically be added to your map.
3) At this time, there appears to be a known issue with the fadeTime API. Thank you for bringing this to our attention. We will fix it in an upcoming release. For now, you can animate the alpha property of the Marker.
4) Once again, the functionality of the BusinessLayer is not directly exposed. If you wish to create similar markers, I recommend you construct the image using Android's Canvas and then adding it as a Marker to the map.
5) If you wish to load the map inside of a fragment, you can accomplish this using child fragments (check Android documentation for more details). You can also accomplish this by instantiating CitymapsMapView or MapView directly and adding it to your view hierarchy either in XML or in code. However if you do this, remember to call the lifecycle methods on your map instance, or else the map will not behave properly.
6) If you wish to have a search in your app, it is up to you to implement this feature. We do not currently provide a search API out of the box.
7) Thank you for the bug report. We will investigate this issue and fix it in a future release.
If you have any more questions, feel free to ask, and thank you for using the Citymaps SDK.

MFC SDI Application, how to change caption of menu item?

The whole day I am trying to solve this simple issue, but without any success.
I found a lot of hints in internet, but seems, that none of them is valid for my problem.
My issue is quite simple: I want to change the caption of a menue item while runtime
But it seems, that all solutions I found are very specific.
My requirements are this:
- it is a MFC application (VS2010)
- It is a SDI application, not MDI
- I want to change the caption of a main menu item (like "File"), not an entry of a submenue.
Because of main entry item, there is no ID for the menu item. Therefore solutions with ON_UPDATE_COMMAND_UI will not work!
My problems are:
- either the code I tried, is generating an assertion or exception
- or the function call returns with false
- or the function seems to work well, but I do not see any result (the caption is still unchanged)
Maybe I am using the wrong functions, or the wrong place for calling the functions.
Has anybody an example, which would work within my application pre-conditions?
Many, many thanks!
Richard
Windows cleverly hides the function to modify a menu under the arcane name of ModifyMenu. I hate it when they do things like that. Really makes me wish for Linux/Unix, with nice clear names like shmdt and mvwaddchnstr. Anyway, getting off my soap box for the moment, you'd call it something like this:
GetParentFrame()->GetMenu()->ModifyMenuW(1, MF_BYPOSITION, 0, L"New Item");
GetParentFrame()->Invalidate();

Wrong View shown (Catel)

I'm trying to open a View with a ViewModel from my MainWindowViewModel.
It works, but all I get is a blank window. It binds the correct title but every other control is missing.
Did anyone have the same problem and found a solution?
You forgot the call to InitializeComponent in your code-behind. Just a tip: create a base class with the Catel behaviors, then use that as a base view. It will keep your actual window code-behind much cleaner.

Core data dirty flag not being set

I have a core data document based cocoa app that is working well except for one slightly odd problem.
For some reason, if I make a change to any of my fields the menu/window don't seem to recognize it - ie. the red close button doesn't get the black 'dirty' indicator and the File/Save menu item isn't enabled. However, if I attempt to close the application (via command-Q), I do get the popup asking me if I want to save my changes.
It seems that the document's dirty flag is being set, but the window/menu items aren't reacting to it. I am curious as to where I might look to see why this might be the case. I suspect that it may have something to do with my window not knowing about my ManagedObjectContext...
The only slightly atypical behaviour is that my document's makeWindowControllers method has been overridden and I am adding my window controllers using a call to my document's [self addWindowController:xxx] method. My window controllers subclass from NSWindowController so I had to add my own instance variable to each window controller to hold the ManagedObjectContext, but I suspect that this isn't getting passed to the window/menu. Not sure what the normal pattern is here...
Anyway, any thoughts would be much appreciated. Thanks
From the description it sounds like your UI elements are not actually bound to the document itself. If so, then the UI elements are not observing the document and are not reacting to changes in the document. Check the bindings.
Thanks in part to TechZen, and also re-reading my own question (in particular, where I said "I suspect that it may have something to do with my window not knowing about my ManagedObjectContext") I started to look at the bindings for my WindowController subclass.
As it turned out, I hadn't bound the window outlet for the File's Owner to my actual NSWindow. As soon as I did that, the black dirty dot and the window's menus started behaving correctly.

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