Is there a way to get a resize effect between two widgets? Like say I have two QTextEdit boxes next to eachother, I want to get a handle between them so I can move it back and forth. Sort of in the same way that the textarea I'm writing in now has a handle at the bottom for making it larger.
I'm using QT Creator and I can't seem to figure this out. I got something similar to what I want by using a QDockWidget, but that really doesn't seem like the purpose for which it was intended.
What you need is a QSplitter.
Related
I'm writing a messenger, and there is a message feed there. As you all know message feeds usually look like lists and go from bottom to top, the keep the scrolling positions anchored to the bottom when a new element is added, they grow upwards when resized and all kinds of fancy behavior like that.
So, I wanted to use QListView to make the feed, I have a model written elsewhere, it's absolutely under my control. But it doesn't seem like QListView supports this mode. There is a trick of how to do it with QML, but I don't have QML used anywhere else in my project and I'm not sure of how to interact with it, like how to set there my model, how to listen for signals or if it's going to behave well in my QGridLayout where I want it to place.
I can't believe no one ever faced the same situation. I'm trying to find the most standard solution, involving as little of my rookie code as possible, keeping in mind that Qt guys are much more experienced in layouting elements in list view and handling all corner cases. If I'm correct my options are
Use QML for the feed
Try to rotate QListView with QGraphicScene tricks
Reimplement QListView
Which of those you think is a better solution? Or, may be, someone knows some better way to do it?
What is the most efficient way of displaying real time plain text?
If I need to display large amount of changing text with high frequency.
What is the best solution?
I have tried QLabel, QPlaintextEdit and I also tried to rewrite a widget's paintEvent and do painting there. But they all do not work very well.
Due to the platform limitation, I cannot use QGLwidget or openGL support.
And the texts need to be grouped in related widgets where the user can perform some basic interaction(like selecting) with those widgets. The expected thing is something like this:
EDIT:
The data comes from many different vehicles' sensors, you could consider that I store the incoming data simply in several arrays. The method I have tried all resulted in a slow responding GUI thread.
I try to create something, where you can drop different things on it, like the Qt Creator (no, i don't want to create a new one, but i need the function of that).
You drag some elements and drop them anywhere in a tabPane.
My problem now is how to make a grid/raster in the background.
It should look similar to this:
I mean those dots in the background.
If I make them with two for loops, it will take hours and it's not efficient or anything else.
There has to be a more efficient solution and a lot easier one.
I'm programming in c++ with Qt as a Framework. Please give me some links or anything else I can use.
You can:
limit the repainting to region that really needs to be updated as explained in QWidget::paintEvent documentation,
fill a container of QPoint in your loops instead of drawing the points, and draw them all with QPainter::drawPoints after the loop,
cache the result in a QPixmap with transparency and reuse it if the window size didn't change (example from Qt Quaterly).
Of course, you should do some testing to see if you gain anything at all by doing any of these optimizations.
I'm having all sorts of size problems with Qt. I am creating my own widgets and using different layouts (generally, I need my own to make them work properly without spending hours on the "powerful" default layouts... which don't lay things out as intended.)
Once I'm done with a widget and its layout though, it doesn't work right. The size is never getting set properly unless I call widget->resize(1, 1); which finally forces a "resize" and makes the widget look correct (i.e. recompute the geometry.) Even the updateGeometry() call has no effect.
This is a dreadful problem when the resize() needs to be called on the parent widget (yuck!) and from what I'm reading should not be necessary were the layouts properly programmed.
Is there a sample that works and is not several thousand of lines long, or does Qt require several thousand lines to make anything work perfectly, even the simplest widget?
What are the minimal functions to be called to make a widget & its layout work at once?
Thank you.
Alexis
P.S. I tried to implement the sizeHint(), minimumSize(), maximumSize(), others that I'm missing? I was hoping that would be enough. Obviously, I also implement the setGeometry() on the layout to resize the children appropriately.
--- addition 1
There is a sample image with a layout that clearly isn't available as is in Qt. The positioning, functions, and colors of the different keys is XML driven and works for any keyboard in the world.
(note, this sample doesn't show the Enter key displayed on two rows and wider below than at the top; more or less, not doable at all with the regular layouts; of course, it works with my version.)
--- clarification
I'm not too sure how to describe the problem better. I was thinking to write a test widget next to see how I can reproduce the problem and then post that and eventually fix it. 8-)
The default layout function that the internal Qt layouts make use of require a lot of coding. I would like to avoid having to copy/paste all of that because for maintenance, it makes it close to impossible.
--- today's findings
As I needed to tweak one of the widgets, I decided to add a VBoxLayout and make it work.
I actually found the problem... One of the widgets in my tree is a QScrollArea and that sizeHint() returns (-1, -1). Not exactly what I'd expect but... whatever you put inside that widget has better know how to compute its width and height or else... it fails.
Looking at the code closely, I could actually compute the width by using the widest width found. Once I used that, the widget would appear (and it actually resizes itself as things change in the list, kinda cool.)
This being said, my earlier comment about having a tree of widgets that auto-resize themselves stands. From the root up to the parents of the leaves in your tree, all of those widgets will need a valid layout. Once I added one in the top widget it resized itself and its children properly (well... in my case up to the QScrollArea, the rest required a bottom to top resizing. Funny how that works!)
--- ah! ha! moment (or: what you find reading the implementation code!)
Today I bumped in another problem which just needed the correct call... I just couldn't find anything worth it in the documentation.
All the objects have a layout now, but a certain parent would not resize properly. Plain simple.
I had a call to the parent as following:
// changes to the children are changing the geometry
parentWidget()->updateGeometry();
Yeah. The docs says that's what you have to do. Nothing happens at all with that call. No idea what it's supposed to do, I did not look at that function. It never did anything for me anyway.
So... I looked at the layout to try to understand how it would send the info up/down. I did not see much except for one interesting comment:
// will trigger resize
This is said of the SetFixedSize mode. To reach that function you need to make the layout for update. Ah! Yes... the layout, not the parent widget... let's try that instead:
parentWidget()->layout()->update();
And voila! It resizes correctly in all cases I have. Quite incredible that the widget updateGeometry() doesn't trigger the same effect...
Although it's possible to do what you want it sounds like the problems you are having are because you're using Qt in a way that it's not meant to be used. Why do you need separate widgets for each key represented on the keyboard?
I see two options, both of which are better in some way:
Use QGraphicsScene and QGraphicsView.
A single custom widget that uses custom drawing to display the keyboard (and likely uses hover for hints).
The first option is probably better. Your keys could then be represented by QGraphicsSimpleTextItem's or even a QGraphicsSvgItem. It also provides a number of standard layouts or you could choose to write your own layout. By default you can use the keyPressEvent or mouseReleaseEvent to respond to user interactions.
I'd highly recommend you take a look at the QGraphicsView examples to get an idea what you can do.
If you go the second route you'll need to record the different key locations so you can respond accordingly as the user moves the mouse around, clicks, etc.
This won't help you with your immediate issue but I wanted to show you a keyboard I made using standard layouts and buttons. It's not perfect and it still won't help you with an enter key that spans two rows but it's not bad. It's resizable too by resizing the window, although I'm not sure if that will be apparent from the images below as SO may be scaling them. (you can view the actual images by opening them in their own tab)
Anyway, this was done using only Qt Designer with no manual coding. It consists of a top level vertical layout with 5 horizontal layouts in it. The buttons are then inserted into one of the 5 horizontal layouts. The size of the keys can be controlled by setting the horizontal and vertical size policies to "ignored" for most of the buttons and then horizontal "minimum" for buttons that you want to be wider. Things can be tweaked by setting min and max size restrictions to buttons. When resized, the buttons will not maintain their relative proportions though, that would probably take some custom programming.
The styling in your example could be approximated pretty well using css style sheets and background images. Still not a minor effort but you should be able to get most of the way there without custom layouts and buttons.
I'm using QT creator and have all my methods etc designed and trying to design a UI and I'm not sure what widget I should be using to reference my puzzle layout.
I've been reading over the documentation for a while and I still am nowhere closer to finding a solution to what I should be using to display my values. I know what I should like but all I seem to find information on is various layouts of entry boxes that are in no way linked. I have no problem with coding it myself to communicate with my classes if I just knew what to use to start off with.
I need something that can help me create a layout that has up to two numbers with positions specific to the type of hint it is with a slash between the hints, black blocks that are neither hints nor stored values and squares that have values that can take up the whole square.
Layout is something similar to http://www.nikoli.co.jp/en/puzzles/kakuro/
I wish I knew what to pick >.<
Personally I'd use QGraphicsView and handle the drawing myself.
It can draw rectangles, triangles, circles and text without much effort, and that's pretty much everything you need as far as I can see. You just need to add the objects to a QGraphicsScene and you get them on the screen. You can also interact with the objects (you can find which object you're pointing at etc.)