LongListSelector - Changing the colour of the current selected item - windows-phone-7

I have a weird situation.
I have a longlistselector with MVVM databinding. When one item get's selected, I change the colour of the text to the phone accent colour. But the item doesn't change its colour on the screen. ( even not when I scroll in the list )
If I then just switch to another page and come back, the item colour is changed if I scroll to it if it is not visible. If it is visible, it still hasn't changed colour until I scroll it out of view and back into view, then the colour will also change.
Anyone the same experience?

If you're changing a bound value but it's not being reflected in the UI then this will typically indicate that you're not correctly notifying of the change. Make sure you're implementing INotifyPropertyChanegd on the viewmodel and calling RaisePropertyChanged appropriately.

Related

Xcode invisible elements

I don't know what happened. Elements items like buttons or segmented control are invisible in main storyboard. Cellphone is the same.
I put the image, of what I mean
It looks like you accidentally changed the view's (or window's) Tint Color to white. (Or you could even have turned it to Clear color, or no color at all.)
This would cause the text of the button or segmented control to be invisible, because it is white on white. The segmented control has a border but it would turn white too. So you wouldn't be able to see anything.
There are two places to look to fix this. Look at the Tint popup of your view controller's View in the Attributes inspector.
Also look at the Global Tint popup in the File inspector for the whole storyboard.
[EDIT It turned out to be the Global Tint.]

change ListView item image at runtime (firemonkey)

I need the ability for a user to press and set an ListView item's checkbox independently of clicking on the item. If they press on the checkbox I will add/remove the checkmark and take some action. If they press on the item text I can take another action.
I can do this with a ListBox no problem with built in functionality. I can't figure out how to do it with a ListView. How is it done?
I can put the following code in the ListView1ItemClickEx to know when the user is clicking on the image. Maybe I can just change the image to a checkmark?
if (ItemObject->Name == "I") {
ShowMessage("Item Image clicked");
}
But I don't know how to change that particular items image (e.g. I could just toggle between a checkmark image and an unchecked image) at runtime.
The picture below is for clarity. Clicking anywhere in the red box will change the items checkbox. For the ListBox clicking anywhere in the blue box will fire the OnClick event and not change the checkbox. I want that same behavior in the ListView.
Ok, Remy answered this related question and it helped me solve this issue. Now I can make the ListView have a checkbox that functions like that of the ListBox. I do it by toggling the item image whenever the user presses (or clicks on) the image area of an item.
When the user clicks an items image I trap it (per Remy's code in the ListView1ItemClickEx event) and toggle it from 0->1 or 1->0 in a vector at reference ItemIndex (e.g. myVector[ItemIndex] = 0) and then I completely rebuild the ListView (clear it and build from scratch).
I thought I'd have to remember where in the list I had scrolled down to and after refreshing the ListView I'd have to scroll to that point in code - but, that isn't the case. I don't know why but after the refresh I'm still at the point in the list where I clicked an item image. It makes it work and feel exactly like a check box.
It works great in iOS, Android, and Windows.
p.s. I forgot to mention that you need to treat any Header's like they are items in your vector that keeps up with each items' image (0 or 1). Otherwise adding headers gets you out of sync and clicking an item's image will toggle some other item's image.

How to mimic the item highlight behavior of NSTableView in NSCollectionView?

I have NSCollectionView with custom items which contain NSTextField and NSImageView.
I realized highlight behavior of collection view items manually (ie. redefined the setSelected: method in my NSCollectionViewItem descendant class).
I successfully change the background color of selected items, but I miss one small but important thing: the text color of the selected item doesn't change.
I know that the NSTableView item highlighting changes the text color along with the background color, but I cannot mimic it since I don't know the algorithm of color's change.
The text color of my NSCollectionViewItems can be different. When I highlight the item in NSTableView, the gray text becomes lightgray, black becomes white and so on.
Does anybody know how they do that? Maybe there's a ready solution in the Cocoa API that I missed? Please help.

Set ListItem foreground dynamically

I have an array that populates a ListBox in my app. At first I need to set the foreground of each listboxItem to gray, and that's easy enough through Binding the foreground color to the listboxItem.
The problem comes in where I then have to seperately (based other back end factors) set specific listboxItems foreground to black. The trick being to select a specific item on the already populated listbox and re-set the foreground without having to re-render the entire listbox.
The objects that I bind to the listbox each does have a guid/unique-id. So if I could just select the item on the listbox ('where id=1635135;?), and then set that items foreground to black..
It's quite difficult to explain this a bit more clearly, but if you have any questions please ask! Thanks!
If you implement the INotifyPropertyChanged in your ViewModel, just change the Foreground property to black for the items you want and they will automaticaly change from gray to black in your UI.

NSWindow and text smoothing in NSTableView cell view

I'm writing an OS X app and have a problem with font smoothing in separate window.
I have a text field where you put text and suggestion window which pops up with a list of suggestions according to what you wrote. I'm using View-cell based NSTableView to display those suggestions and SFBPopoverWindowController to display it as a "popup" window (tried other classes with the same effect). When rows are first drawn they look fine but after I select them (keyboard or mouse) the font changes it's weight. It's only visual - like you would change smoothing method on the font, not it's bold setting.
"Music note" is the selected cell here
What's even more strange is that after I hide and show the window 3 times everything works fine from that point on.
Again - "Music note" is the selected cell.
The selection is done by overwriting NSTableRowView class and its drawSelectionInRect: method but I tried with drawing everything inside custom NSTableCellView class and it didn't help. The text is standard NSTextField - nothing's changed there.
The SFBPopoverWindow (and it's controller) are created once and reused with styleMask NSBorderlessWindowMask, backing NSBackingStoreBuffered, defer set to YES. The only change in SFBPopoverWindowController I made was to turn off window becoming key window but it doesn't change anything.
It might be related to the way a table view draws it's selected cells (setSelectionHightLightStyle:). Try to set the style to None/ NSTableViewSelectionHighlightStyleNone in your code or IB / Storyboard-file and draw the selection yourself (in a NSTableRowView subclass).
Background: When you use NSTableViewSelectionHighlightStyleRegular or NSTableViewSelectionHighlightStyleSourceList the table view assumes that you use the standard selection behaviour and appearance and does some magic to support that.
==========
UPDATE
==========
My previous answer is still valid but since it only describes the problem and hints at a workaround, I wanted to add a real solution. If you want to use NSTableViewSelectionHighlightStyleRegular for your table view (with custom font and colors), you need a way to 'disable' the system magic that comes into place once your row is highlighted. One proposed solution is to decline the first responder status. It has a lot of drawbacks and isn't a good solution at all.
So, let's have a closer look at the system 'magic' that kicks in as soon as the row will be highlighted: NSTableRowView has a property interiorBackgroundStyle that is – according to the documentation – 'an indication of how the subviews should draw'. Furthermore 'This value is dynamically computed based on the set of properties set for the NSTableRowView. Subclassers can override this value when they draw differently based on the currently displayed properties. This method can also be called to determine what color a subview should use, or alternatively, NSControls can have the -backgroundStyle set on their cell to this value.'
I assume that this style will be handed down the subview hierarchy and causes your text fields to look odd. The system assumes that a highlighted cell has a dark background and changes the interiorBackgroundStyle to dark. Other controls try to adapt accordingly.
I think there are two solutions to this problem:
1) Override interiorBackgroundStyle in your NSTableRowView subclass and return the style that fits your interface (in my case it's .light because my highlight color is a very bright blue). This worked for me.
2) If changing the whole style is a bit too much because you only want certain elements to not change their style, you may only need to adjust these subclasses. I haven't tried this yet.

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