Develop Reference

Why is the mousedrag and mousepress being used together in the same time ? I want to stop the mouse drag when I'm using mouse press and vice versa

When I press the free button I can draw in the bottom pane but when I press the rectangle button I can draw a rectangle in the panel but I can also draw anything in the same time. My goal is that when I press one of the functions I want the other to stop functioning.
public class MyFrame extends JFrame implements ActionListener, MouseListener , MouseMotionListener{
JPanel top;
JPanel bottom ;
JButton btn1,btn4;
int freebtn,rectanglebtn;
Graphics g;
public MyFrame(){
this.setTitle("car");
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setSize(700,700);
this.setLayout(null);
this.setResizable(false);
top = new JPanel();
bottom = new JPanel();
top.setBounds(0, 0, 700, 100);
top.setBackground(Color.blue);
bottom.setBounds(0, 100, 700, 600);
bottom.setBackground(Color.white);
btn1 = new JButton("free");
btn4 = new JButton("rectangle");
btn1.addActionListener(this);
btn4.addActionListener(this);
top.add(btn1);top.add(btn4);
this.add(top);
this.add(bottom);
bottom.addMouseMotionListener(this);
bottom.addMouseListener(this);
this.setVisible(true);
g=bottom.getGraphics();
}
// action listener-------------------------------
#Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
if(e.getActionCommand() =="free") {
System.out.println("free button");
freebtn=11;
}
else if(e.getActionCommand() =="rectangle") {
System.out.println("rectangle button");
rectanglebtn=12;
}
}
// mouse listener-----------------------------
#Override
public void mouseClicked(MouseEvent e) {
// TODO Auto-generated method stub
}
#Override
public void mousePressed(MouseEvent e) {
// TODO Auto-generated method stub
System.out.println(rectanglebtn);
if(rectanglebtn==12) {
g.setColor(Color.BLUE);
g.drawRect(e.getX(),e.getY(), 100, 50);
}
}
#Override
public void mouseReleased(MouseEvent e) {
// TODO Auto-generated method stub
}
#Override
public void mouseEntered(MouseEvent e) {
// TODO Auto-generated method stub
}
#Override
public void mouseExited(MouseEvent e) {
// TODO Auto-generated method stub
}
// mouse motion listener---------------------------
#Override
public void mouseDragged(MouseEvent e) {
// TODO Auto-generated method stub
System.out.println(freebtn);
if(freebtn==11) {
g.setColor(Color.BLUE);
g.fillOval(e.getX(),e.getY(),20,20);
}
}
#Override
public void mouseMoved(MouseEvent e) {
// TODO Auto-generated method stub
}
}
I tried to to set one of them to null when I'm using the other but it didnt work

Let's start with...
#Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
if(e.getActionCommand() =="free") {
System.out.println("free button");
freebtn=11;
}
else if(e.getActionCommand() =="rectangle") {
System.out.println("rectangle button");
rectanglebtn=12;
}
}
Apart from the fact that you are using e.getActionCommand() =="rectangle" instead of "rectangle".equals(e.getActionCommand()) (see How do I compare strings in Java?, for more details) , once either freebtn or rectanglebtn are actioned, the values they set never change.
So, for example, if I press the rectangle button, rectanglebtn is set to 12. If I then press free button, rectanglebtn is still 12
Instead of using two different (and somewhat unrelated) variables, you should be using a single "state" variable. Now, if you have more than two states, I would use a enum, for example...
enum State {
FREE, RECTANGLE, CIRCLE
}
And then update the action handler to something like...
private State state = null;
// action listener-------------------------------
#Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
if ("free".equals(e.getActionCommand())) {
System.out.println("free button");
state = State.FREE;
} else if ("rectangle".equals(e.getActionCommand())) {
System.out.println("rectangle button");
state = State.RECTANGLE;
}
}
Now, whenever either button is actioned, the state is changed to a single state.
Then your mouse listener begins to look something more like...
#Override
public void mousePressed(MouseEvent e) {
// TODO Auto-generated method stub
System.out.println(state);
if (state == State.RECTANGLE) {
g.setColor(Color.BLUE);
g.drawRect(e.getX(), e.getY(), 100, 50);
}
}
// mouse motion listener---------------------------
#Override
public void mouseDragged(MouseEvent e) {
// TODO Auto-generated method stub
System.out.println(state);
if (state == State.FREE) {
g.setColor(Color.BLUE);
g.fillOval(e.getX(), e.getY(), 20, 20);
}
}
and there is no way that they could become cross wired.
Now, onto the "other" issues... g = bottom.getGraphics(); is NOT how custom painting works. At best, this will return a "snapshot" of what was last painted and at worst, it will return null.
You need to look at Painting in AWT and Swing and Performing Custom Painting to get a better understanding of how painting in Swing works and how you should work with it.

KeyListener on a disabled button

I have a series of buttons in my code. I have added key listeners to individual buttons to listen to keys, so that when user presses RIGHT, LEFT,UP DOWN, I can transfer focus to the next button.
Note: I know that TAB can be used
now everything works really great! but when the focus is at a disabled button. I am not able to listen to it.
Any suggestions, as to how I can go around the problem?
Please pardon me before hand for amateur coding style!
addEntry.addKeyListener(new KeyListener() {
#Override
public void keyTyped(KeyEvent e) {
// TODO Auto-generated method stub
}
#Override
public void keyReleased(KeyEvent e) {
// TODO Auto-generated method stub
}
#Override
public void keyPressed(KeyEvent e) {
if(e.getKeyCode()==KeyEvent.VK_RIGHT)
{calPeriod.setFocusable(true);
calPeriod.grabFocus();
}if(e.getKeyCode()==KeyEvent.VK_LEFT)
{
getTime.setFocusable(true);
getTime.grabFocus();
}
if(e.getKeyCode()==KeyEvent.VK_DOWN)
{
genChart.setFocusable(true);
genChart.grabFocus();
}
}
});

JTabbedPane click event

I need to be able to process a click on the tabs in a JTabbedPane. I'm not using this to change tabs, and this isn't going to trigger on tab change. What I'm attempting to do is close the tab when it is right clicked. However, I'm not sure how I can access the tab to add a click event on it. Most of the questions related to clicking on JTabbedPanes suggest using a ChangeListener, but that won't work, since the tabs aren't going to be changed on right click.
Is there any way for me to add a click event to a JTabbedPane's tab?

Is there any way for me to add a click event to a JTabbedPane's tab?
Read the section from the Swing tutorial on How to Use TabbedPanes for a working example on how to close a tab with a mouse click.
Keep a link to the tutorial handy for Swing basics.

Sorry for late answer, but I found this very usefull for me and for avoid extra clicks detected by stateChanged (with this you can detect all you want in "click tab"):
myJTabbedPane.addMouseListener(new MouseListener()
{
#Override
public void mouseClicked(MouseEvent e) {
// TODO Auto-generated method stub
System.out.println("Panel 1 click");
}
#Override
public void mousePressed(MouseEvent e) {
// TODO Auto-generated method stub
}
#Override
public void mouseReleased(MouseEvent e) {
// TODO Auto-generated method stub
}
#Override
public void mouseEntered(MouseEvent e) {
// TODO Auto-generated method stub
}
#Override
public void mouseExited(MouseEvent e) {
// TODO Auto-generated method stub
}
});
Finally, if you want to detect right click on tab you can see next tutorial (search getModifiers() in next page):
https://docs.oracle.com/javase/tutorial/uiswing/events/mouselistener.html

Java mouse listener lacking responsiveness

I made a little color selector using JPanels and mouse listeners, but for some reason the result isn't as responsive as expected and I don't know why.
in order to do so I created a modified JPanel I called ColorPanel, to add it a few properties like color and color name, built in mouse listener, background color defined when instanciated etc:
public class ColorPanel extends JPanel{
private Color color;
private String sColor;
public ColorPanel(Color color, String sColor){
this.color = color;
this.sColor = sColor;
this.setBackground(color);
this.setBorder(BorderFactory.createLineBorder(Color.white));
this.addMouseListener(new appMouseListener());
ColorSelector.panSelector.add(this);
ColorSelector.vPanel.add(this);
}
public Color getColor(){
return this.color;
}
public String getScolor(){
return this.sColor;
}
class appMouseListener implements MouseListener {
#Override
public void mouseClicked(MouseEvent e) {
// TODO Auto-generated method stub
ColorSelector.select((ColorPanel)e.getSource());
}
#Override
public void mouseEntered(MouseEvent arg0) {
// TODO Auto-generated method stub
}
#Override
public void mouseExited(MouseEvent arg0) {
// TODO Auto-generated method stub
}
#Override
public void mousePressed(MouseEvent arg0) {
// TODO Auto-generated method stub
}
#Override
public void mouseReleased(MouseEvent arg0) {
// TODO Auto-generated method stub
}
}
}
this is linked to another object I made meant to instanciate all the panels I need and their countainer, as well as the method to change the selected colorpanels border color and store its coulour into a global variable.
While it works, every so often I got to click several times to select a colorpanel. The program had no responsiveness problem before and that selector is the only thing behaving this way.
public static void select(ColorPanel colorPanel) {
IhmMap.SelectedColor = colorPanel.getColor();
IhmMap.SelectedScolor = colorPanel.getScolor();
for(int i = 0 ; i<vPanel.size(); i++ ){
vPanel.elementAt(i).setBorder(BorderFactory.createLineBorder(Color.white));
}
colorPanel.setBorder(BorderFactory.createLineBorder(Color.red.darker().darker()));
}
This is the method, all the panels are added to a vector upon creation, so I can manipulate them easily.

MouseClicked event only fires if you didn't move the mouse at all between pressing and releasing the mouse. That way if you press the mouse button and move the mouse slightly just by 1 pixel, the mouseClicked won't get called.
I suggest using mouseReleased or a combination of mousePressed, mouseReleased and/or mouseExited. e.g.
private boolean pressed;
#Override
public void mouseExited(MouseEvent arg0) {
pressed = false;
}
#Override
public void mousePressed(MouseEvent arg0) {
pressed = true;
}
#Override
public void mouseReleased(MouseEvent arg0) {
if (pressed) {
//your code here
}
}
That way you can press on the ColorPanel and as long as you don't leave the ColorPanel it will register a click.

Window events for JFrames that are hidden/shown via setVisible?

Which kind of listener do I have to add to a JFrame to detect when it is being hidden or shown via setVisible?
I tried using a WindowListener and the windowOpened and windowClosed methods, but they only work for the first time that a window is opened (windowOpened) or, respectively, when the window is closed using the dispose method (windowClosed). That is not enough for me. I want to be notified every time the window is made visible and invisible on the screen using setVisible.
Is there a standard Swing way to achieve this, or do I need to make my own (by, say, overriding the setVisible method)?

Try a java.awt.event.ComponentListener. You can add one using this code (where window is the name of the JFrame) :
window.addComponentListener(new ComponentAdapter() {
public void componentHidden(ComponentEvent e) {
/* code run when component hidden*/
}
public void componentShown(ComponentEvent e) {
/* code run when component shown */
}
});

1- Create a class that implements ComponentListener Interface, Like the following example:
//---------------------
import java.awt.event.ComponentEvent;
import java.awt.event.ComponentListener;
public class winlistenner implements ComponentListener {
public void componentHidden(ComponentEvent arg0) {
// TODO Auto-generated method stub
System.out.print("Hided\r\n");
}
public void componentMoved(ComponentEvent arg0) {
// TODO Auto-generated method stub
System.out.print("Moved\r\n");
}
public void componentResized(ComponentEvent arg0) {
// TODO Auto-generated method stub
System.out.print("Resized\r\n");
}
public void componentShown(ComponentEvent arg0) {
// TODO Auto-generated method stub
System.out.print("Shown\r\n");
}
}
//------------------------------------------------------------------------
2- Now create a getter for your JFrame like this:
public class JMain {
private JFrame frmNetworkshareMoon;
private JTextField textField;
private JTextField textField_1;
private JTextField textField_2;
public JFrame getFrmNetworkshareMoon() {
return frmNetworkshareMoon;
}
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
JMain window = new JMain();
winlistenner listenner= new winlistenner();
window.getFrmNetworkshareMoon().addComponentListener(listenner);
window.frmNetworkshareMoon.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
//......
// the rest of your class code:
//...
}
3- being your main like the above example, you will set JFrame listener the listener you created, and then run the program, you will see messages coming from the listener:
Moved
Resized
Resized
Moved
Shown
Moved
Moved