I created a frame using NetBeans. The frame has two buttons A and B. Button A is initially disabled. It is to be enabled only when button B is clicked.
public newFrame() { //newFrame is the name of the frame that has buttons A&B
initComponents();
btn_A.disable();
}
private void btn_BActionPerformed(java.awt.event.ActionEvent evt)
{
btn_A.enable();
}
The problem is that button A becomes active/enabled when the mouse is moved over it ie inspite of whether button B is clicked or not. How can i fix this?
I want button A to be enabled only after button B is clicked and not as a result of any other event.
Use btn_A.setEnabled(false) instead of btn_A.disable()
btn_A.enable() is a deprecated method.
To do this task, you could replace it by btn_A.setEnabled(false); to disable the button and btn_A.setEnabled(true); to enable the button.
Also, one more suggestion is, add statements like the following in your method if you feel something wrong happening:
System.out.println("Some statement relevant to the method");
The main aim of those extra statements being you know when the method was actually executed.
Try the following code:
button. addMouseListener(new MouseAdapter() {
public void mouseEntered(MouseEvent me) {
button.setEnable(true);
}
public void mouseExited(MouseEvent me) {
button.setEnable(false);
}
});
Related
I am designing Reversi game in java, and the structure is as follows:
a. A JFrame with 64 buttons in it. The buttons are stored in an array.
b. The JButtons will have black circles or white circles.
So whenever a move is to be made, the program will highlight those boxes where a move can be made, but how can I know which button (I want to know the index of that button) has been clicked when all are highlighted the same way?
From my understanding, you are attempting to detect when a specific JButton is pressed.
The simplest way to do this is by implementing an ActionListener.
public class ExampleClass implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == buttonNameOne)
System.out.println("Button One was pressed");
else if (e.getSource() == buttonNameTwo)
System.out.pringln("Button Two was pressed);
}
}
Detecting an action
The actionPerformed(ActionEvent e) method will activate whenever any button is pressed.
Recording source of action
When it is pressed, it automatically detects the source of this action (the button) and stores it in parameter "e".
Using recorded source of action
By simply doing e.getSource() you are able to get the component which invoked this method and compare it to pre-existing components in your program.
Customized arguments
With each if statement, you are able to customize and personalize the result of the condition (which is if the button being pressed is equal to a specific button). Do this by putting arguments within the body of each conditional statement:
if (e.getSource == sayHiButton)
System.out.println("Hi");
You probably have one ActionListener added to all buttons. Then the ActionEvent getSource passed to performAction has info. That is ugly, like testing the button text.
What is more normal is to use Action (take a look) and setting different actions bearing the 64 states.
public BoardAction extends AbstractAction {
public BoardAction(int x, int y) { ... }
#Override
public void actionPerformed(ActionEvent e) {
...
}
}
JButton button = new JButton(new BoardAction(x, y));
In an Action you can also specify the button caption, and an Action can also be (re)used in a JMenuItem and such.
Because of the extra indirection needed, most examples use an ActionListener,
but swing interna use Action quite often. For instance having an edit menu with cut/copy/pase and a toolbar with cut/copy/paste icons, context menus.
I have this strange problem when I add buttons to the toolbar. I added action listener to one button added before the frame is shown and it works fine:
btn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
toolbar.add(new JButton("new button"));
}
});
I also added a piece of code that is supposed to add a new button after some plugins are loaded, and for some reason that piece of code does not work.
#Override
public void handle() {
System.out.println("Button added");
MainFrame frame = Application.getInstance().getMainFrame();
frame.getToolbar().add(new JButton("Plugin button"));
frame.getToolbar().revalidate();
frame.getToolbar().repaint();
System.out.println(frame.getToolbar().getComponents().length); // It is definitely being added, just not shown
}
The button is definitely being added, just not shown.
I would really appreciate any help since this thing is blocking me from progressing any further.
I found out what the problem was. The problem was that I instantiated MainFrame twice, first by calling Application constructor in main and then when calling Application.getInstance(), so all components added to the MainFrame were removed.
I cant seem to find a way to prevent a SwingWorker from being called twice on a double click.
The issue is that simply setting the JButton to setEnabled(false) doesn't prevent someone from double clicking fast enough to run it more than once.
startButton.addMouseListener(new MouseAdapter() {
#Override
public void mouseReleased(MouseEvent arg0) {
makeItSo();
}
});
private void makeItSo () {
startButton.setEnabled(false);
myWorker myW = new myWorker();
myW.execute(); // Executes allot of work. But errors if this is running more than once.
}
Don't use a MouseListener for buttons, you should be using an ActionListener
See How to Use Buttons, Check Boxes, and Radio Buttons and How to Write an Action Listener for more details
Use ActionListener instead of MouseListener
why you use ActionListener, An ActionListener is used to handle the logical click of a button.
A click happens
- when the mouse is pressed then released on a button,
- when the keyboard shortcut of that button is used,
- when the button has the focus and the space bar is pressed,
- when the button is the default button and Enter is pressed,
- when the button's click() method is called programmatically
A MouseListener only handles low-level mouse events.
1> I have a JButton in Jframe.
2> The click of JButton opens new instance of another JFrame.
The problem is when a Key is pressed very fast on the above Jbutton .Two instances of the same JFrame opens up.
I have to open these frames. I knows there are other options also not using the Jframes as I read.
I managed to solve this problem for Doulbl click of Mouce by setMultiClickThreshHold('time in miliseconds'). But it worked only for mouse.
Tried some other stuffs which I got in google, But none worked.
Is there any other way to solve this issue?
For full control of how often/quickly again an Action is triggered, implement it to disable itself in its actionPerformed. Something like:
singlePerform = new AbstractAction("DoSomthing") {
#Override
public void actionPerformed(ActionEvent e) {
setEnabled(false);
doSomething();
}
};
JButton button = new JButton(singlePerform);
When it's safe for doSomething to be triggered again, simply re-enable the Action:
singlePerform.setEnabled(true);
Is it possible, in Java, when you hover over a single button, to make the program think you are hovering over multiple buttons?
I'm using a multi-dimensional array with buttons and want to be able to have 5 buttons be hovered over at a time. (All the buttons near the actual hover).
Any ideas on how to do this?
Note: I'm not using JButtons, just regular buttons. (awt.Button)
EDIT
I obviously wasn't clear enough, and I apologize for that.
Here is a screenshot of what I'm looking for:
So, the cursor is hovering over the first gray space, and all of the space next to it have a different background, however, they are not considered as being hovered over, which if what I need.
Assuming you are using a MouseListener, when the mouseEntered(MouseEvent e) method is called on the master button, explicitly call the same method on all of the listeners of all of the other buttons, passing the event you have been given. Ditto for the mouseExited(MouseEvent e) method.
It's up to you to maintain a reference from the master button to the subordinate buttons.
The subordinate buttons' listeners will receive an event that refers to the master button. If necessary, create your listeners with a reference to the button that they are attached to, so that you can operate on that button when receiving an event.
EDIT:
This is the kind of thing I'm talking about. Does it help?
final List<Button> subordinateButtons = Arrays.asList(new Button(), new Button(), new Button());
Button myButton = new Button();
myButton.addMouseListener(new MouseListener() {
public void mouseEntered(MouseEvent e) {
for (Button subordinateButton : subordinateButtons) {
subordinateButton.setBackground(Color.GRAY);
}
}
public void mouseExited(MouseEvent e) {
for (Button subordinateButton : subordinateButtons) {
subordinateButton.setBackground(Color.LIGHT_GRAY);
}
}
public void mouseClicked(MouseEvent e) {
}
public void mousePressed(MouseEvent e) {
}
public void mouseReleased(MouseEvent e) {
}
});
There's no reason why you can't keep a reference from a MouseListener to a List<Button>. If it's the business of the listener to work on those buttons then design your classes so that it happens.