Is there any way to create a custom component in swing. By custom I mean say right now I am able to create a circle and do actions like dragging it etc.
But now I also want that along with the circle a text label with its number is also present. Can we combine them into a new type of component where say we can do actions on it collectively?
If yes please give me pointers on how to do so.
Yes, just extend JComponent and handle painting and interaction however you want. If there is a component that already does most of what you want you could extend that class and tweak it slightly.
I would suggest reading some of the tutorials about how JComponent works:
http://download.oracle.com/javase/tutorial/uiswing/components/jcomponent.html
Here is a similar question but I am sure you can find more specific ones that have been asked once you get deeper into it.
How to create a custom Swing Component
The Swing tutorial as a whole if very useful to understand how other components work etc.
http://download.oracle.com/javase/tutorial/uiswing/components/index.html
You can create your own Swing component extending JComponent. Several question here on Stack on the topic like this one.
Personally, I advise you to get this book: Java Swing as it contains an excellent guide on how to create Swing components.
Related
I can make control extending Composite or Canvas.
How to make it selectable? I.e. how to make it behave like Button? Button is disabled for extend. I see a lot of unportable code inside it.
So how to make Button-like control of myself?
Should I process mouse and keyboard events myself or there is some premade functionality to utilize?
You will have to handle the events yourself. I'll give you a couple of hints and references here:
First of all, make sure you read this: Creating Your Own Widgets using SWT
Have a look at SquareButton. It's a custom Button widget and should contain all the code you need.
Here is a very related SO question.
Hope this helps.
Canvas is for drawing from "inside". So, you have to create your own UI input. As here.
I've got a custom component GameViewCanvas extends JPanel that will hold a number of tiles (800x800 textures). Now in GameViewCanvas I've overridden the paint() method, so that it will paint the children on a transformed canvas (zoom, panning and rotation).
I now want to delegate events like MouseEvent and MouseMotionEvent to the respective children - the problem of course being that Swing has no idea where the children are on the actual frame. I thought I might be able to just override a method like getComponentAt in the parent but no such luck - I figure Swing is looping through the children directly?
Maybe I'm going about this all wrong, so please advice.
Thanks in advance.
Take a look at JXLayer. It does exactly what you've just asked.
There are some excellent examples by Piet Blok, which have, unfortunately, disappeared off the net. To this end, I've made them available here.
Take a look at the TestWrapped demo in the pbjar source. It is probably the (among) the best example.
ps - JXLayer is now officially part of Java 7, known as JLayer
In Adobe After Effects there is something called a "pick whip". It allows you to click on a dot on one object and drag a line from that dot to another element, making a connection between the two. I would like to duplicate this feature in my Java program using swing. I honestly have no idea where to start.
If I've done a bad job explaining what I mean, please comment so I can improve it. If there is some way outside of Swing to do this, I'm willing to try it.
Here are some examples of what I am trying to achieve:
LinePanel illustrates how to animate the line as it is rendered, but you'll have to paint on the glass pane or among JLayeredPane instances to see the line above existing components.
I fear I'm just making a ten-times duplicate question, but I've been trying to Google this for quite some time without finding anything, neither in general nor even here on SO, so I'm starting to think it's worth a shot.
I'm wondering, is there a good guide on what is necessary to implement an AWT widget in Java? What needs to be implemented in order to respond to such things as redrawing, resizing, placement, focus behavior and all other such things as widgets may or should do, in a proper manner? All the articles I manage to find describe the process from the perspective of a user of widgets, never from the perspective of the one implementing them.
Also, what would be the primary differences between implementing an AWT widget and implementing a Swing widget? Is there even a difference from the implementer's point of view?
Probably the best way to learn how to write an AWT widget would be to look at the source code for an AWT widget. Here's the source code for the java.awt.Frame class.
I haven't worked with AWT much, but Swing is much better from the GUI developer's point of view. The only difference that I know about from the implementer's point of view is Swing's usage of Listeners.
Again, you can look at the source code to see what's different. Here's the source code for the javax.swing.JFrame class
Not too much difference aside from the fact that AWT widgets are simpler.
You extend one of the 4 classes: Component, Container, Canvas, Panel. The first two are heavyweight, the latter two are lightweight (don't have native window system peers). Override paint(Graphics) (or update()) and getPreferredSize() to make it visible, then look into javadocs for overriding event handling methods.
Sure you know this link, http://docs.oracle.com/javase/6/docs/api/java/awt/Component.html
I'm trying to build a new java swing component, I realise that I might be able to find one that does what I need on the web, but this is partly an exercise for me to learn ow to do this.
I want to build a swing component that represents a Gantt chart. it would be good (though not essential for people to be able to interact with it (e.g slide the the tasks around to adjust timings)
it feels like the best approach for this is to subclass JComponent, and override PaintComponent() to 'draw a picture' of what the chart should look like, as opposed to doing something like trying to jam everything into a custom JTable.
I've read a couple of books on the subject, and also looked at a few examples (most notably things like JXGraph) - but I'm curious about a few things
When do I have to switch to using UI delegates, and when can I stick to just fiddling around in paintcomponent() to render what I want?
if I want other swing components as sub-elements of my component (e.g I wanted a text box on my gantt chart)
can I no longer use paintComponent()?
can I arbitrarily position them within my Gantt chart, or do I have to use a normal swing layout manager
many thanks in advance.
-Ace
I think that the article i wrote a few years ago for java.net is still correct today. Doing everything in one monolithic class gets you going faster in the beginning, but becomes a mess quite fast. I highly recommend doing the separation between the model (in your main class) and the view (UI delegate). The view is responsible for:
interaction with the user - mouse, keyboard etc.
painting
creating "worker" subcomponents as necessary
In the medium and long run this is the approach that has been validated over and over again in the Flamingo component suite, which you can use as an extra reference point (in addition to how core Swing components are implemented).
Using UI delegates is a good idea if you think that your component should look different for different Look And Feels. Also it is generally a good idea from design point of view to separate you presentation from your component
Even when overrding paintComponent you can still put any sub components on it.
Using null layout you arbitrarey position your components. Alternatively you can use layouts too.
Here is a very good starting point for you.