Dynamic JList implementation - java

I have a list of entities where each entity render into widget based on JPanel. Widgets have dynamic behaviour - once placed on panel it can be changed by underlying entity. This happens automaticaly. Moreover some widgets can be resized by different actions, on button click for example.
The question is how to organise them into something like JList but without rubber stamp technics. In other words I wanna JList where each item rendered with cellrenderer stay "alive".
Right now I have implemented quick-and-dirty component based on JPanel with vertical BoxLayout, it uses JList's renderer component and it's model... but my implementation is too dirty...
Um.. yeah, using JTable is not suitable too.
Do you have some ideas?

If you don't want rubber stamping to take place then you'll have to create your own JList implementation that uses actual components.
You could try and work around the rubber stamping effect by caching each component for each row in your renderer and bind values into it and return that instance when JList asks the renderer for it. This is pretty risky because if you have 20 rows being displayed you'll have to cache 20 instances in your renderer, and only when the row isn't visible can you reuse one. That would mean if you had 5 unique configurations (A,B,C,D,E) of components you might have 10 of type A, 5 of type B, 2 of type C, and 3 of type D, and 0 of type E being displayed. However, you can't simply reuse one of those components without knowing if its being displayed or not. So you'd have to take into account if the row is being displayed and if it's the right type for the row you are rendering. And you'll have to clean up after the row is hidden.
Another option is make a single component for the row that encapsulates all X variations you have and put those on a CardLayout. Then you can simply cache one per row being displayed, and simply swap the card being displayed upon rendering that row. I think that might be the simplest option for you.
The harder part is going to be routing events click mouse clicks, keyboard events, etc to those active components to have them respond like normal components. Re-rendering the buttons when the user clicks them, and so forth is going to be challenging. Not impossible, but tedious.
Finally, variable row height JList is a pain. Especially in your calculations to figure out if a row is displayed or not because you can't simply do easy math like: int rowHeight = jlist.getHeight / model.size(). It doesn't work. You have to calculate each row's height and them up to figure out if a row is visible or not.
Doing what you're talking about is a lot of work, and very tricky coding to work around some of the assumptions of JList to make it work. In the end you might find it easier just to implement your own List control that makes different design decisions. Either way its going to require you are good at Swing to get it to work.

Ok. I don't find any implementation of such component. Let it be first one.
https://github.com/wertlex/JActiveList
P.S. I don't think this is proper way implementation... but it works.

use JList and ActionListener XD

Related

Creating set of JButtons according to retrieved database values

I'm working on a POS system for a fast food restaurant. I've developed Adding, updating and deleting products using a MySQL Database. Now I need to create the POS GUI (using SWING) which the cashier uses to create the bill. The interface I have in mind is like what MacDonald's uses, there's a set of buttons with the product images. (I have stored BLOBS of products successfully)
example image :
I have no idea on how to accomplish this, it would be awesome if its possible to generate a set of dynamic Jbuttons which gets the image of a product along with the name and price. Is this the best way to accomplish this? and how do I achieve this? A few details to put me on the correct path will be greatly appreciated!
Thanks.
You have at least four containers, the top row, the bottom row and each row containing a separate container in the middle (for the buttons).
The basic layout for the rows might be a GridLayout, each row would probably use a BorderLayout with the nav buttons in the WEST and EAST positions. CENTER container could use a GridLayout, but won't give you the look you're after. You could use a FlowLayout and even a GridBagLayout, but you'd need to ensure the size of the buttons where correct for your needs
On the left I see a JTable and two JPanels, containing the buttons, held together with a GridBagLayout.
On the right I see a JList. See How to Use Lists for more details. You'll probably also want to have a look at Concepts: Editors and Renderers and Writing a Custom Cell Renderer for details about how you could customise the look of the cells and How to Write a List Selection Listener for details about how to determine when the user changes the selection
Together, they are probably maintained by a GridBagLayout within a single container for ease of use
Along the button is probably another container using a GridBagLayout.
Altogether, they are probably held together by a GridBagLayout
Have a look at Laying Out Components Within a Container, How to Use GridBagLayout, How to Use BorderLayout and How to Use FlowLayout for more details
You will need to look into the GridLayout.
In your case, it might be a little bit more complex since you have multiple grids, some of which seem to be nested within each other.
You should be able to allocate the grid dynamically and then leave it to the layout manager to distribute things evenly over the page.
Depending on the complexity of your layout, it might also be a good idea to look into the GridPane provided by JavaFX.
Hi I look for you this problem and I find this solution ;
http://www.javasrilankansupport.com/2012/06/create-dynamic-jbutton-with-image-and.html

GridBagLayout: changes alignment after adding checkbox

I have two classes which creates two different dialog box. Both the classes have same code, except one has additional lines of code, which creates a checkbox
first Class, with Checkbox
Second Class, without Checkbox
There is slight alignment difference in "save" button. How can I fix this.
Is there a particular reason you're using fixed row and column sizes? One of the great features of GridBagLayout is its ability to center/align and fill. This also tends to make things look better on different screen sizes, different fonts, etc.
To answer your specific question, my guess is that the checkbox is taller than the row you're putting it into, pushing the next row down.
When I debug GBL, I often set row/column background colors to different things and print out (or view in a debugger) sizes of the things I'm trying to fit into the container.
I had to adjust the row height as the checkbox was taller than the row and was pushing the third row downward( Thanks to Ingrid Biery). so I changed the 2nd row height from 25 to 30 and it worked.

Get foreground (font) in a particular JTable cell

There are many answers to how to set the font (use renderer), but I want to get this font. The reason why is for unit-testing: test for the renderer doing its job OK.
The human eye can see whether a component for a given cell is rendered with a red foreground, but how can we do this programmatically?
later Just a word about my comment "get hold of the screen real estate". That's not quite it: each one of these table cells contains something... but what? And is it possible to reference it? It almost seems that each one is the "ghost" of the component (the same one) used successively to render each individual cell. Obviously I don't really know about the "architecture" of the representation of a JTable. Would be interesting to find out... although I suspect strongly that these "ghosts" (or whatever) are inaccessible.
Use the JTable.prepareRenderer(...) method.
This method will return the Component that will be used to do the rendering of the cell. So you can then invoke the getForeground() method on the Component.

Java GUI architecture for larger project

I want to make an app, which will work as interface to several servers.
Why: In web iface provided by default (and we cannot change it) are few things we miss, few could be done better and for sure automation of some stuff would make the job easier.
What do I have: almost finished classes for communication with web interface of a server app.
GUI description:
For some kind of version 0.1: text field for username, radio button to select server and one "go" button. Then several (4-12) action buttons to operate on data, 2x text area with results, one label with some text data - I can manage this.
Then I need to view the data - grid MxN which will load the data, expected size: 7-15 columns, usually 10 rows or less, but rarely it can go over 1k (or even more, but I don't need all to be visible to the user in that case).
What I need: simply an advice.
I wish to start with a simple version (and I'm working on that already, but I'm stuck on too many things - 95% cos and absolutely new to GUI and 5% cos I'm new to java).
I've checked many tutorials, but they're all simple.
Real questions:
1) Verify. In MVC controller should handle all user actions - is it done by view's method which is something like button.addActionListener(param); anotherButton.addActionListener(paramp; ...?
1b) I've seen all implemented via one (nested) class, which was then checking source or smth - is that ok? There will be a lots of buttons etc.
2) How to implement the data grid, when I need to take actions on click / dbl click?
4) First row is header, the rest should be scroll able - should it be in the grid or outside (its own grid):
4a) How to make sure header's size (width) will be the same as in data (I don't want to set up straight size)
4b) I failed to create anything scrollable so far, but thats my bad I guess. How to ensure header will hold on a place and the rest can be scrolled?
5) How should be "data update" implemented? I've got JPanel from which I remove grid component and then I make new one and add data into it (simple, but perhapss there is another way). One of first enhancements will be sorting - use the same way I used for new content?
Thanks a lot for any answer, I know this is not very specific, but example I've found are too simple.
I plan a lots of enhancements, but thats in the future and I don't mind to rework GUI/Controller several times, at least, I'll practise, but I don't want to finish one part of the code and realise I've got to rewrite half of a controller and 1/4 of a view to make it possible.
Note: I plan to use this at work as my tool (if things go right, I could make 25-50% of my work by few clicks :-)
So I really mean this).
Note#2: I'm not new to programing, but I've never created GUI (which is why I've got GUI with menu bar with 2 items and 3 components and almost done web-iface connections).
Note#:3 dragable data header, tabbed data view - thats the plan for the future :-)
MVC in Swing is examined here; use nested classes for ease in prototyping and creating an mcve for future questions; as the need arises, nested classes can be promoted to separate classes having package-private access.
Use JTable; its flyweight implementation of renderers is good for organizing data by row and column.
Item three does not exist, but "always remember to translate cell coordinates" if you plan to drag columns or sort rows.
Use a JScrollPane to keep the table header stationary.
Update the TableModel, and the listening view will update itself in response.
If you are interested not only from the event/messaging architecture, but also on handling mouse/keyboard input, hovering detection, widgets, temporary menus, form re-sizing with widget alignment, dragging and dropping etc. I can advice you to look at this question and my answer with helpful resources.

Choosing appropriate layout for this specific situation

I'm trying to figure out how to manage this layout in order for it to work. I have some ideas, but rehauling the whole thing is quite a bit of work to do.
This is how it looks like (in JTextAreas: "component name (parent (parent))"):
I have explaind the structure at the end of the question, if you feel the need to know.
This GUI is supposed to be very dynamic. You should be able to add and remove chapters, pages, questions and answers.
The GUI in the image above is made using nested JPanels (up to six layers on the thickest parts!) which most don't have thier size specified so they can adjust to the changes in the document. However, a lot of time is consumed (about a second per page) when drawing the document because the program keeps recalculating sizes of all the JPanels until they fit. So, unless I can specify the initial size (MigLayout) of a component, this method won't cut it for me.
Only alternative I have come up with is trying to put it all in one layer using MigLayout, which is doable, but I don't know how well does it work with the dynamic part of the whole thing. Removing and readding all the components (document could have over a hundred pages!) doesn't really seem as an option. Since most of the components are nested one onto another and are to move as one, this makes this solution even more difficult.
Also, all widths are fixed, while all of the heights within a page are flexible.
I really don't know how to go about this. Should I modify one of the existing ideas to work, or are there maybe libraries which are used in this type of situations? Is there another way?
Any ideas?
Also, as promised, this is the structure explained:
So, the thing important here is the JPanel inside a tab. It contains the DOCUMENT.
Document itself is made up out of random number of CHAPTERS. Each CHAPTER contains random number of PAGES. PAGES have MARINGS and CONTENT. On the image, pink and red parts are the MARGNIS, while everything within is CONTENT(green). CONTENT contains a single TITLE(blue). TITLE is made out ofa single JTextArea. After the TITLE, CONTENT can contain a random number of QUESTION(orange). QUESTION contains a JLabel(number) and JTextArea in one row, and below is a it's ANSWER PANEL. ANSWER PANEL contains up to five ANSWERS(yellow). Each ANSWER has a JCheckBox, JLabel (letter) and a JTextArea all in the same row.
Here I have some things marked out:
You seem to have the design you need. Break down each section and apply the required layout to achieve that section. Each section should be a self contained component.
So to my mind, start by modelling the data. You need a Document model, which contains a list of Chapters, which contains a list of Pages, which is made up of a list of Titles, which is is made up of a list of questions.
I would then provide a view for each level of the model. This will allow you to concentrate on the individual needs of each view, in isolation and reuse the code logic. It also means if you need to make changes, they will be more easy to make and reflected through the entire program
You seem to have the right idea for the Document/Chapters, being laid out within tabs.
I'd follow through. Each Page would be a self contained component, possibly using something like a GridLayout.
Each Content section would be its own component, consisting of the title editor and then the questions.
Here I'd use a BorderLyout, placing the title editor at the north position and the question panel in the center. You could then use something like a GridLayout for the questions pane.
As for the margins, you can achieve hese through the use EmptyBorders

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