I'm writing a diagram editor in Qt with Graphics View Framework.
Currently I'm just trying to create a simple Node (QGraphicsItem) on GraphScene (QGraphicsScene). I created a Canvas (QGraphicsView) and added a grid to it. I can even add Nodes and move them around on scene. My final goal is to have different working modes, editing and styling options, etc. For now I just want to know how can I setup selection for Nodes already present on scene. I tried doing it with mouse events but noticed that event calls for selection and Node insertion overlap... When I try to select something a new Node is created... This is my first Qt application so I don't fully understand how the functionality I want to achieve should be designed.
How the Selection Rectangle should be properly drawn?
How should I manage mouse events that conflict with each other?
You can use a checkable button/action(that's a QPushButton/QAction with a checkable property set to 'true) to switch between Edit & Insert mode. Then you check the state in your mouse event and insert a new item only if you're in Insertion mode.
You can also distinct between mouse buttons - insert item when dragged with the right button for example
Or use QKeyboardModifiers - for example: on drag + Ctrl - insert item.
Hope this helps.
In case of the overlapping mouse events, you should have a single place (like QGraphicsView to handle the mouse clicking/moving events) and create a state machine and then handle the events according to the state you are in. You need to plan your architecture well and that can be really complex task.
set your state enum/constants
refer to the current machine state in your events in your if conditions
keep your "business logic" on a single place
Like it's shown in these two NodeEditor tutorials #11 and #12: https://www.youtube.com/watch?v=pk4v2xuXlm4 and https://www.youtube.com/watch?v=-VYcQojkloE)
If you still want more in depth explanation of the functionality and events of Qt, here is a full list of tutorials with implementing all possible features like dragging edges to nodes, selecting them and deleting them, cutting edges, serialization, etc., you can have a look on the whole list of 50 tutorials I've recorded here: https://www.blenderfreak.com/tutorials/node-editor-tutorial-series/.
I'm putting a link to the whole list, since it's not possible to write all the code on this page...
Related
I'm new to flutter and I'm looking for a way to implement a simple feature. A draggable container.
I have two groups of UI elements wrapped in a Container widget. I want to be able to go from one group to another by dragging or swiping in different directions.
How would I go about doing this?
Here are sample images of my UI design to help you understand what I want to achieve:
Image #1
Image #2
As you can see, Image #1 and Image #2 are only different in the bottom part of my design. I have already created all the necessary UI elements and wrapped them in the Container widget. Now the only thing I need is the ability to go from one group to another. It would also be nice if there was a callback method that could update the buttons above upon transitioning from one group to another.
Thanks in advance!
There are many possibilities to achieve this, depends on your exact wishes, here are 3 ideas:
Using a TabBarView to swipe the entire screen, Tab1 will be the first screen you showed, and Tab2 will be second screen - only the contents. (you probably did not want that, but just putting it out there).
Dividing the container into 2 pieces (vertically), and placing the TabBarView on the bottom part, having 2 tabs: 1 with the Today part and one with the Weekly part. (there are a few examples out there, for instance: divide screen into two equal parts in flutter).
You can also customize the build method to change anything (for example the top indicator) based on the current tab index (as asked and answered here: How to get current tab index in Flutter)
For a more custom solution you can use:
GestureDetector wrapped around your container, and handle OnHorizontalDragX (where X is Start, End etc.) to do any custom stuff - maybe changing the state and trigger a rebuild with the new image
I am looking for a control many of us probably know, but I don't know it's name and don't have a real screenshot by hand, just this sketch:
In the left box one can select an operation or whatever, which then is moved to the right side. With the up/down arrows on the right, one can move this operation (or whatever kind of meaning the entry has) up or down in the order of execution.
How is this kind of control called? Or is it normally build by developers out of single controls? Is this control available in JavaFX 2? If not, I don't need exactly this control, but a control with the following features:
User can select multiple operations (duplicates allowed) out of all available operations
The user can arrange their order of execution
Thanks for any hint :-)
You need to use multiple controls to build up your interface. Use two ListViews with a MultipleSelectionModel for each (or at least the left one) and add a couple of buttons, that copy selected items from one list to the other and another couple of buttons which modify the position of selected items in the right list view by modifying the view's underlying item list.
listView.getSelectionModel().setSelectionMode(SelectionMode.MULTIPLE);
I need to implement a threaded view of sorts in an old VB6 app. It should look similar to this:
So, it's like a TreeView of sorts but there are buttons on the right (for each row) that could be pressed. The view does not need to collapse - it always stays in the expanded mode. The users should be able to respond to each node (via the comment button on the far right). And, of course, users should be able to scroll through the entries.
What are some of the ways I could implement this? I am open to 3rd party controls, paid or not.
VSFlexGrid has an outline mode. You can set the indent per row via the RowOutlineLevel property. It supports word wrap, images, etc within its cells/columns so you should be able to get pretty close to what you want. It also supports owner-drawn which lets you fully customize the cell painting (for example, to get those rounded corners).
I'm sure there are other controls out there as well...
I have a project that I'm working on that has a TreeView Control in it. For everything underneath Level 1, those nodes are being used as a bookmark function, so we want a Tri-State CheckBox there. I found a control that I'm using here.
However, as the top two levels in the TreeView do not need bookmarking, the customer wants an Image there. I found this page who's response gets CheckBoxes to disappear on specific Nodes. Unfortunately, the API calls clash with the ones used in the above Tri-State TreeView and they both can't work at the same time.
Basically, what I'm looking for is how to get Images in nodes on the top two levels, and Tri-State CheckBoxes on the lower levels. I'd be more than willing to try another Tri-State CheckBox if necessary.
Also, when the user clicks on the Image in the top two levels, the image shouldn't change. I found this page which does keep the image from changing, but removes the PlusMinus, Lines, and RootLines from the control.
Sorry in advance that this is such a ridiculous and specific request.
Ok, I finally got this figured out. Using the Tri-State Treeview Control, I am able to still have access to the AfterClick event on the Treeview.
I had added a series of Checkbox icons to the ImageList, and after determining which CheckState (of the 3) my underlying object was in. Then I set the ImageIndex, SelectedImageIndex, and StateImageIndex (probably don't need the last one, but I was being thorough) to the proper index of the ImageList.
I won't post any code for now, but if you are trying to do the same thing, let me know and I'll upload until it becomes clear.
I've found many answers, here or inside MS' UI guidelines, regarding button positioning, but none about how to position (in which order) buttons when you have three actions to do, New, Edit and Delete.
I have a simple UI, in the upper part I placed a grid listing some data. Beneath, these three buttons. Following what I see around, I have to place them in this order:
New - Edit - Delete
But it seems to me that the delete button is more prevalent and easier to reach and click than the others (it falls on the lower-right corner of my window).
Any suggestion?
I think the order you cite (New - Edit - Delete) is most common because you would logically tab order from left to right when using the keyboard. New would arguably be the most used button (possibly edit depending on the application, but rarely delete) and therefore you wold want the fewest tabs to get to the New button.
Column layouts are always good for these kind of buttons, as one has to move the cursor into the button area, which is horizontally slight and therefore less likely to be accidentally clicked.
Also it provides a perceived division from the main GUI widgets, instead of spanning their length, which tends to create less of a perceived division in the user's mind.
But if you do not wish to change the overall layout, I would say that your current layout is good. Maybe add a delete confirmation box if one is not already present.