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Passing mouse control to JComponent which is not drawn inside JFrame

I‘m currently trying to render and use JComponents and it’s ancestors in a Custom Java Canvas. Right now, I‘m trying to create a Menu which should be clickable and it displays just fine inside my canvas when drawn with JComponent.draw(g). But the last piece I‘m trying to solve is that it should also react to the mouse-events the canvas generates (like hoovering over a JButton, clicking a JButton, etc etc). I only found listeners for events generated by the component…
So, is there any way I can tell a JComponent to not use its mouse events but instead pass through the events from somewhere else?

How can I change colors of components when the mouse is pressed in a JFrame in Java?

I am coding a piano in java using rectangles from the java.awt.graphics library. I am using a mouselistener to play the sound of each individual key when the mouse clicks a certain area on the JFrame.
How would I add a shape to the panel upon clicking, repaint, then repaint the keyboard back over top when the user releases the mouse?

Consider adding JLabels to a JPanel that uses GridLayout. Give each JLabel a MouseListener and either swap ImageIcons on mousePress/mouseRelease or change the JLabel's background with press and release. If you go the latter route, you'll want to make sure that the JLabels opaque property is set to true so that the background colors show.
Then for the black keys, you can add the above JPanel to a JLayeredPane and on top of this, add another JPanel that holds the black keys that function in the same way.
Also, you'll want to take care to "play" any notes in a background thread, such as can be obtained with a SwingWorker so as not to tie up the Swing event thread and completely freeze your program.

Consider solution: source
It might not be exactly what you're after, but it might give you an idea of how to approach your problem. It took me a long time to figure out how to use JLayeredPane without setting a null layout, but in the end this was the best I could come up with. Also, assumed some naming conventions for your sound files. :p

Clickable images in Java

I'm making a point-and-click escape type of game. I'm wondering, if there's an easy way to make clickable images? I'm going to use photographs as background and also as items that the player has to collect. So, is there an easy way to make the items clickable and also disappear after clicked (player collects it).
Thanks for answers, and if my explanation was complicated, please say and I'll try to fix it.

For making a game I'd recommend bringing all the logic one level lower.
Create an data structure which will contain the state of your game "level". This data structure will be loaded from some kind of XML level configuration file, and I think it should contain:
A Image object containing the level background (photo).
An array of all items. Each item should have an Image, dimensions on the level screen (X,Y,Width,Height) and some kind of state (visible, highlighted, etc.).
Make a class which extends Canvas. This will be the component which will contain and render your whole game screen (with items, and background photo).
Override it's paint method. In this paint method use drawImage method go through your level data object (specified in step 1) and draw the background (room) and all the items in their respective coordinates. If the item has visible = false - don't draw it. If it has selected = true - draw some highlight around it or whatever you want.
Implement a MouseListener. This listener should check if click coordinates are inside the dimensions of one of your "objects" on the screen (loop through all clickable objects). If it is - do appropriate action (for example increase score and set visible = false for that item) and update your canvas with repaint. This will trigger the paint method again drawing all the changes on your canvas.
Register a MouseListener on your Canvas with addMouseListener to tie it all together.

If you're using Swing, simply set the icon of a JButton. This will create a "clickable image".

There are several ways, the most straightforward being using a JButton and setting an icon on it. But you can also add a MouseListener to any Component (like JPanel) and set an image as background (override paint).

You're going to probably do something like this: Draw a JPanel and then position a bunch of JLabels on it, and each label will draw it's own image too.
If you have a specific code question, we can be more help, but you're being very general. Try working through the Swing examples on the java web site and then ask more targeted questions.

You can set the image to a JButton object as background. The key point is that you should listen to the mouse click event and JButton is the first choice to satisfy this requirement.

A simple example on how you can get a clickable image. For more examples and explanations on java Swing and awt you can look at the official java tutorials here.
//a lable holding an image
JLabel label = new JLabel(new ImageIcon("MyImage));
//Add a mouse listener to get the click event
//
label.addMouseListener(new MouseAdapter(){
public void mouseClicked(MouseEvent e) {
System.out.println("Mouse clicked (# of clicks: "
+ e.getClickCount() + ")", e);
}
});

Handle overlapping components in java swing

I am working on an app which when used for loading a file and drawing the contained components, may result into painting of overlapping components. For example, consider a big rectangle box containing text line inside it.
Now because these components are overlapping, it is difficult for the user to select the inner text box in this case as it has been overlapped by the rectangle box.
We were thinking of solving this with allowing the users to actually move any component to a layer below the current one. But this has its own limitations on the usability side, as then for every such case the user will have to move the bigger or the most recently painted component to a layer below and then do the other processing on the inner components like dragging etc. There can be more than 2 components at the same 2d (x & y position) in this app.
I am sure that there should be a better solution for this and could someone please provide some pointers on the implemention part of it.

I am not sure, whether i understand your question. Do you have problems, with the action listeners or because of drawing the components?
This How to Use Root Panes may be helps.
You can create a Glasspane in Java

Here's a simple example of an object drawing program that supports click and drag for multiple selections. More advanced programs often implement z-order functionality (Move Forward, Move Backward, Move to Front, Move to Back) by simply re-ordering the node list.
As an alternative to the layered pane approach, also consider JInternalFrame. This example shows How to Use Actions to manage a menu from which hidden windows may be brought to the fore.

Swing: Floating panel next to the selected item in a JComboBox

I've created an app with a small window (the size of a combo box). I need to create a floating panel that sits outside the window, next to the selected item in a JComboBox. (See attached image).
I've been reading about the JComboBox.setRenderer(customRenderer) etc. But was just wondering before I go down this path, whether it is at all possible to render something outside the window. I suspect it is, as the combobox itself manages to render it's popup list outside the window.
I'm very new to Swing, so any advice would be appreciated.

It's not possible with the custom renderer since Swing components are light weight. That is, Java is given a native window and all the component drawing takes place in that window. In your case, that is the JFrame containing the combo box.
What you can do though is create a new undecorated window and set it's location accordingly and draw whatever you want inside it.
EDIT: When Java needs to paint outside it's window bounds (like the case of pop up messages or combo boxes drop downs) if the component falls inside the bounds it uses the swing light weight mechanism. But if the component falls out side the bounds it is automatically substituted with a awt heavy weight component that has it's own native drawing surface outside the active window.

I've implemented similar idea using combobox renderers and tooltips on them. Content of every item's tooltip can be customized and rendered using HTML. Location of the tooltip can be set outside of the item itself thus creating design very similar to the one presented in your question.
Here is the starting point for you:
http://www.java2s.com/Code/Java/Swing-Components/ToolTipComboBoxExample.htm