I am trying to display multiple icons to the Treeview item but it is not displaying all the icons, it displays only one.
I am using the following code:
CImageList m_imageState;
m_cTree.m_imageState.Create(16, 16, ILC_MASK, 0, 4);
m_cTree.m_imageState.Add(&bm, RGB(255,255,0));
m_cTree.m_imageState.Add(&bm2, RGB(255,0,255));
m_cTree.m_imageState.Add(&bm, RGB(255,255,0));
m_cTree.m_imageState.Add(&bm1, RGB(0,255,255));
m_cTree.SetImageList( &(m_cTree.m_imageState), TVSIL_NORMAL );
But when I see Treeview, item displays only one icon.
Is it possible to display multiple icons with Treeview item?
Please suggest how can I do this.
Correct, only one icon will be displayed per item in a TreeView control. This is by design, a hard limitation of the native control that the MFC library wraps.
The only way you're going to be able to display multiple icons per item is owner drawing. It's a pretty difficult task for a TreeView control, not nearly as easy as owner drawing a button or a label control. Make sure that you really this need this functionality, and consider whether there's a better way of displaying the relevant information to your users.
Alternatively, you could create custom bitmaps that combine multiple images next to one another, and add those to your ImageList. The resulting images will be wider than they are tall, but the control doesn't care: it will display whatever size images you specify, as long as all the images in the image list have the same dimensions. This is definitely a hack, but it might work, depending on your needs.
Related
My app needs to be small in nature so I make it 500 x 100 px in size.
The problem is the ComboBox selection items are also squeezed into that small window size. Of course, I can scroll it, but it doesn't feel right this way.
Here is the picture:
Is it possible to expand the ComboBox selection list so that it exceeds the parent window? Preferably in XAML if possible
Is it possible to expand the ComboBox selection list so that it exceeds the parent window?
No, this is impossible in UWP apps. While using ComboBox class, it displays the drop-down list in PopupRoot, which is a layer has the same view port as its parent window. Anything outside this view port will be clipped, users can't see them. For example, following is a normal ComboBox:
After I give a Margin="-20,-30,0,0" to the drop-down list, it looks like
The part outside the window is clipped.
Besides, The implementation of ComboBox will also make sure the ComboBox's selection list won't exceeds the parent window. The selection list's max height is calculated at runtime, it will be always less than the parent window's height and we can't change its value manually, so it is not possible to expand the ComboBox's selection list.
It's not possible, but you can extend your page to the title bar to have at least some additional space using CoreApplicationViewTitleBar.ExtendViewIntoTitleBar property.
Take a look here and here. (I know the examples are written in C# but it should be similar in C++)
I am in the process of making a Roku channel. The idea is to have a full screen player going, if the user presses a particular button on remote, a small pop up menu will display in a corner of the screen with a list of available channels. I have all working with the following exception: I can't figure out how to populate the area where the menu displays. Currently I have a transparent roImageCanvas on layer 1, the menu box is drawn on layer 2. The problem is that roImageCanvas allows for a text element but only one Item. So if I have a list of 10 channels, I would have to create 10 items on the canvas. The roImageCanvas does not accept arrays. So there is no way to create the pop menu on the fly if the number of channels changes. The number of items on the canvas has to be hard coded as far as I can tell. Ideally the roListScreen is what I would like to pop up but from what I understand all screens are full screen all the time. Does anybody know of a way to populate the targetbox on the canvas or create a screen that is resizable? Thanks for any suggestions
A roImageCanvas layer is an array. There is no technical limitation to you adding >1 elements to a layer and so you can add as many separate text items as you want (not hard-coded!). It seems to me best to have 1 text element per 1 menu item, so you can use their bounding rectangles (or text color) to highlight the choice
I have a collection of images, dynamically generated through QGraphicsView widgets, and i'd like my users to choose between them. For that purpose, i would display inside a custom widget available images in some kind of grid and have users click the one they are interested in.
Multiple questions arise :
is there an existing widget that already fits this purpose ?
should i find a way to disable all mouse event handling by QGraphicsView items, or could i add a transparent widget in front of graphic views which would intercept them ?
is there a performance issue displaying many QGraphicsView widgets (up to a few hundreds) ? Should i export them to plain images first ?
First off, no, there's no widget designed specifically for that purpose.
I don't think you are grasping what QGraphicsView is for. It's for displaying a QGraphicsScene, which is meant to hold many QGraphicsItems. Based on your post, I can't see why you would need multiple QGraphicsViews. You can simply have one QGraphicsView and display many images inside of its scene. For example, see QGraphicsPixmapItem.
You definitely should not have hundreds of QGraphicsViews. You probably just want one (although a few could be justified in certain circumstances), in which you display many QGraphicsItems in a QGraphicsScene. You can definitely have hundreds of QGraphicsItems visible at once. In your case, you probably want QGraphicsPixmapItems, which are a subclass of QGraphicsItem. You could even have multiple QGraphicsScenes, and display whichever one is relevant using QGraphicsView::setScene. If you want the user to be able to select an image from a grid, and then work with that image, I would look to the State Pattern.
I can't think of any reason to disable mouse handling in QGraphicsViews, QGraphicsScenes, or QGraphicsItems. Why should these not handle their own mouse events? You can (and should, where necessary) subclass them and reimplement mousePressEvent, mouseMoveEvent, mouseRelease event, etc. to obtain the functionality you want.
Good luck!
I have an instance of QDialog, populated by widgets using code generated by uic. The dialog contains a few labels laid out vertically, and I am popping the dialog from time to time to show some text in these labels. The text can be multi-line and its length is not pre-determined. I set the vertical size policy to fixed, so the user can't drag it (doesn't make sense), but I also want the dialog to change its size before being shown to accomodate for the current size of the labels.
To this end, I was calling QWidget::adjustSize() on the QDialog before displaying it, but it doesn't work as expected. When the dialog is shown, it seems to retain the (wrong) size from the previous displaying, but when I click the mouse in the (disabled) vertical resize mode, the dialog suddenly "snaps" to the (correct) adjusted size.
Is there any way to make my dialog appear correctly?
EDIT: I tied rubenvb's advice, and ended up with this:
QSizePolicy free(QSizePolicy::MinimumExpanding, QSizePolicy::MinimumExpanding);
QSizePolicy fixed(QSizePolicy::MinimumExpanding, QSizePolicy::Fixed);
dialog->setSizePolicy(free);
dialog->adjustSize();
dialog->setSizePolicy(fixed);
dialog->show();
Unfortunately, that didn't seem to change anything.
This isn't the answer you're hoping for, and it may not apply to what you're trying to do, however, the only way that I was able to adjust the dimensions of a QWidget at run-time was by handling the object's resizeEvent(..) method. This allowed me to calc the size of items based upon the font being used, number of lines, available space, etc., and then adjust their size accordingly before passing the 'event' on to the base resizeEvent(..) method.
My approach used a single QWidget container within a window, below a header, above a footer status area, and to the right of a column of menu buttons. The widget container, inside the resizeEvent() call, would look at the objects it was going to display, calculate the font heights being used, and then resize some items according to their dimensions (because of how the style sheet selected fonts and colors, etc) and then adjust the sub-widget dimensions before allowing the container widget to get the resizeEvent() message.
So I wasn't so interested in setting a window size, but I think the container QWidget might work the same way? I was more interested in setting the dimensions to some asthetically pleasing size, depending upon the dimensions of the display.
Hope you find that helpful.
Do everything in the right order:
Dialog is not shown. Dialog is resizeable.
Calculate new size, set new size.
Set dialog to not-resizeable.
Show Dialog.
Hide dialog, go to step one.
Just curious about scrolling complicated content inside web browser - like application. Lets assume i am using Qt and C++. This is not "how to" question, but more like "how does it work"? Completely derived from my curiosity irrational questions.
I did small experiment.
Created large QWidget 800x60000 px.
Added 300 QWidgets 800x200 px that are painting themselves using QPainter. Each widget prints its unique name to console when paintEvent() is called.
Added (1.) to a QScrollArea 800x800.
When scrolling, i notice redrawing only widgets that are not fully displayed on the screen. It is only 1 widget at a time (scene: http://savepic.ru/2670640.jpg).
So QScrollArea (or QWidget? Who deside what widget to repaint?) is smart - we do not have CPU loaded redrawing all the 300 widgets all the time or memory consumption storing 800x60000 pixmap (-;
Lets assume i want to use mouse to select text and other elements on my "webpage". So i want to be able to mark them (by changing background). How would i implement that? How different web browsers do that? Selecting pictures, text, tables... Should i think about tracking the mouse and drawing gray/blue/pink background boxes behind elements and my custom widgets?
I have another experiment - displaying stack of messages. The scheme is the same, except QPainter is not used here - only QLabels, QTextExits, QPushButtons (scene: http://savepic.ru/2632728.jpg). I can set a flag SelectableByMouse for QLabel, but how do i select more than 1 message?
You could suggest me to use some Qt HTML renderer, but this is not the answer for 'how does it work".