I am working on a FLEX / AIR Spark list which lists a collection of images with differing width and height.
I am using a custom layout which works this way:
decide how many images can be fit in the current row based on their widths.
justify them in such a way that first image in the row obeys the "left" margin and the last image in the row obeys "right" margin, so with the "top" and "bottom" as specified by the user, let us say 10 pixels.
As an example, assuming that the current row has 4 images, the images 1 & 4 will have 10 pixels each as "left" margin "right" margin respectively. But the left and right gaps between 1-2, 2-3 & 3-4 will be equally divided based on the varying widths.
now i would like to draw a background that will fill the dynamic area. Please see the image below to get an idea:
Layout requirement Image
** In the image, The grey area is the background I would like to draw, and the colored rectangles represent images of differing widths and heights.**
the "rowHeight" is variable based on the maximum height of individual images within the row.
Issues:
a) Now I would like to draw a background (see the grey area in the pic) that fills the background area of the list. I know the current item's width & height, but I don't know the rowHeight decided by the layout, left and right margins between the images.
Something like:
bgRect:Rectangle = new rectangle ( 0, 0, (imgWidth + (LeftMargin/2) + (Right Margin/2) ), rowHeight)
b) How / where should the background be implemented? if i add the BG area within the item renderer based on the layout, again the layout will be relaid.
Children should be added in the createChildren method. Drawing (painting) the background should happen in updateDisplayList method.
You can pass data to your itemrenderers via an itemrenderer factory. See - Flex - Sending a parameter to a custom ItemRenderer?.
var productRenderer:ClassFactory = new ClassFactory(ProductRenderer);
productRenderer.properties = { showProductImage: true };
myList.itemRenderer = productRenderer;
Related
I have a tableview cell that contains a horizontal UIStackView. Inside it is an UIImageView (on the left, 100x100 dimensions) and a vertical UIStackView (on the right) that contains 4 labels. The vertical UIStackView is constrained to the UIImageView's top and bottom anchors. But the bottom constraint is "less than or equal to".
I am setting the text property on these labels but if the text is nil I hide that label. Stack View than sets the height of that label to 0 and it doesn't appear in the Stack View. Now the idea is if some labels are hidden, the combined intrinsic content size's of the remaining labels will define the height of the vertical UIStackView and it will decrease in height based on that "less than or equal to" bottom constraint.
This doesn't work though. Take the case where the 2nd and 4th labels have been hidden. The 1st label is normal height. But the 3rd label stretches all the way down to the bottom of the UIImageView. This is in contrast to my expectation that the intrinsic content sizes of the labels would be less and the label's UIStackView would shrink.
I'm guessing there is some priorities that might need to be tuned to get this working properly. This whole view hierarchy is contained in a UITableViewCell and that has dynamic height applied which I hope doesn't cause any problems.
So if the intended behavior is that when I hide labels the vertical UIStackView shrinks, what constraints must I add/delete or which priorities must be set?
For exemple, I want the value of the layoutLeftMargin property to be equal to 1/3 of the parent widget. So when I will resize the windows, the ratio of the widget will still stay the same.
Else, if it's not possible with QtDesigner, how can I do it with code ?
No, Margins are specified in pixels, they can't be relative to the parent widget's size.
However, You can do that in the designer by putting your whole current layout in a Horizontal Layout, add a Horizontal Spacer to the left of it, assign suitable layoutStretch values in the horizontal layout (In your example, this should be 1,2, meaning the original layout will take up twice the space taken up by the spacer, so that the spacer gets 1/3 of the parent widget).
I'm developing an app with a complex hierarchy of widgets and layouts, but in short it has a central widget with a formulary as upper widget and a QScrollArea as buttom widget (by means of a QVBoxLayout).
That QScrollArea represents a list (grid layout indeed) of QPushButtons which can contain a huge number of buttons (or not).
I want my app fits the following constraints:
Both (form and list) consume all available horizontal space, redistributing its contents to fill all horizontal space (nor SpaceItems neither contents margins).
Both must save as vertical space as possible, in order to make "lines" close to each other.
I've solve partially my problem making use of setSizeConstraint(QLayout::SetFixedSize) on the form, which shrinks it vertically, but also horizontally, causing that both, list and form, have different widths, wich doesn't look like very well.
How can I achieve that? I mean, how can specify something like grow horizontally to fill the widget but shrink vertically has much as possible?
Add a spacer as the last item to the layout:
gridLayout->addItem(new QSpacerItem(10, 10, QSizePolicy::Expanding, QSizePolicy::Expanding), lastrow, 0);
I think this is what you want:
If you know how many columns you will have (and it doesn't change), insertStretch() in the last column (although it might give you the same effect as using a spacer).
int columnCount = gridLayout()->columnCount();
gridLayout->insertStretch( columnCount(), 1 ); // Default stretch for other
Note that this will resize your buttons to the size Qt thinks they should be unless you are explicitly changing their widths.
I had a layout all nicely designed in Qt, but as soon as I clicked on the parent window and set it to a grid layout, things got all wonky. I've read every tutorial I can find as well as the Qt designer manual and just cannot figure out why this is happening. I have attached a screenshot to show the problem:
As you can see, the vertical layout on the left insists on being wider than the children it contains. Both the label and the treeview are set to sizePolicy maximum, and the maximum width is set to 260px. The children themselves stay the correct size, but the vertical layout that contains them doesn't.
The vertical layout in the middle is set to expanding, and the one on the far right is setup the same as the one on the left, only that one appears to work. How do I make the first vertical layout conform to it's children's width?
Also, if I may sneak a second question in, I have a QTextEdit inside the tab widget in the lower right, but it will not fill to take up the space of the full tab view. You can't see that in the screenshot, but if I pull the tabview up, the textedit within it doesn't stretch with it. How do I make it conform to the size of the tab? It's already set to sizePolicy expanding, but that doesn't seem to help.
The problem is most likely that you need to experiment with "stretching" the layout. Stretch sets the size of layout cells in relation to each other. The default is 0, which means no stretching occurs.
In your case, I believe you want to set the stretch of the first column (column 0) to 0, and the stretch of the second and third columns to 1. This means that the first column will always be as small as possible, and the second and third columns will try to be equally wide.
You can set the stretch programmatically quite easily; for example, to set the first column to stretch 0:
layout->setColumnStretch(0, 0);
In Qt Designer you can access column and row stretches as any normal properties.
I'm having trouble using the layout manager system with Qt. This is going to be a Symbian app, so it should resize to different devices.
This is done by using the Layouts.
On the image below I used the Vertical Layout, but I don't understand how I can decide how much each cell should take in width and height.
I want the blue to be a top label background, but I don't want it to be as high as it is now.
Does anyone know how I can do this? (I'm new to Qt :))
You can set the maximum size for a widget by right clicking it and selecting 'Size Constraints'. Under that menu you can find actions that allow you to set the current displayed size as the maximum / minimum size for vertical / horizontal or both directions.
You can also set the numbers by hand by selecting the widget and by setting the number in the 'Property Editor'. They should be under the QWidget properties.
You cannot set the Height of a vertical layout directly, but you can set the height of the widget in which the vertical layout is.
If you want to split your Widgets so that the top widget takes 33.33% of the space, use the Stretch values. Set the top widget to 1 and the bottom widget to 2.