Is there a better way to create an actionListener to JButtons in a for-loop?
Question
I want to create a number of JButton s which symbolize a specific time-intervall. All JButton s share basically the same actionListener : They mark their specific intervall as "free" ("Frei") or "not free" ("Belegt"). To do that, they not only just have to change text, but they have to call a method of another class, which uses their intervall as @parameter . I create the JButton s with naming JLabel s like this:
for (int i = 1; i <= numberOfIntervalls; i++) {
String toolTextString;
if(controller.getCalendar(calendarName).isFree(i, controller.getDayString(year, month, day))) {
buttonText = "Frei";
toolTextString = "Belegt";
}else {
buttonText = "Belegt";
toolTextString = "Frei";
}
if(i%5 == 0) {
gridx = 1;
buttonGridy += 2;
textGridy += 2;
}else if(i < 5){
gridx = (i%5);
}else {
gridx = (i%5) + 1;
}
intervallButtons[i-1] = new JButton(buttonText);
intervallButtons[i-1].addActionListener((ActionListener) this);
intervallLabels[i-1] = new JLabel(intervallLabelBuilder(i));
intervallButtons[i-1].setToolTipText(String.format("als %s markieren", toolTextString));
GridBagConstraints gbc_btnNewButton = new GridBagConstraints();
gbc_btnNewButton.insets = new Insets(0, 0, 0, 5);
gbc_btnNewButton.gridx = gridx;
gbc_btnNewButton.gridy = buttonGridy;
contentPane.add(intervallButtons[i-1], gbc_btnNewButton);
GridBagConstraints gbc_labels = new GridBagConstraints();
//gbc_lblNewLabel.insets = new Insets(0, 0, 5, 5);
gbc_labels.gridx = gridx;
gbc_labels.gridy = textGridy;
contentPane.add(intervallLabels[i-1], gbc_labels);
}
}
my actionListener -method is this because I know that numberOfIntervalls = 12 , for quik ajustments, the numberOfIntervalls should be a variable, but it s static and final`:
public void actionPerformed (ActionEvent e){
System.out.println("-----------");
if(e.getSource() == intervallButtons[0]){
if(!controller.getCalendar(calendarName).isLoaded(controller.getDayString(year, month, day)))
controller.getCalendar(calendarName).summonDay(controller.getDayString(year, month, day));
if(controller.getCalendar(calendarName).isFree(1, controller.getDayString(year, month, day))) {
controller.getCalendar(calendarName).setFree(1, false, controller.getDayString(year, month, day));
buttonText = "Belegt";
intervallButtons[0].setToolTipText("Als Frei markieren");
}else {
controller.getCalendar(calendarName).setFree(1, true, controller.getDayString(year, month, day));
buttonText = "Frei";
intervallButtons[0].setToolTipText("Als Belegt markieren");
}
intervallButtons[0].setText(buttonText);
intervallButtons[0].setEnabled(false);
intervallButtons[0].setEnabled(true);
}else if(e.getSource() == intervallButtons[1]){
if(!controller.getCalendar(calendarName).isLoaded(controller.getDayString(year, month, day)))
controller.getCalendar(calendarName).summonDay(controller.getDayString(year, month, day));
if(controller.getCalendar(calendarName).isFree(2, controller.getDayString(year, month, day))) {
controller.getCalendar(calendarName).setFree(2, false, controller.getDayString(year, month, day));
buttonText = "Belegt";
intervallButtons[1].setToolTipText("Als Frei markieren");
}else {
controller.getCalendar(calendarName).setFree(2, true, controller.getDayString(year, month, day));
buttonText = "Frei";
intervallButtons[1].setToolTipText("Als Belegt markieren");
}
intervallButtons[1].setText(buttonText);
intervallButtons[1].setEnabled(false);
intervallButtons[1].setEnabled(true);
}
else if (e.getSource() == intervallButtons[2]){
if(!controller.getCalendar(calendarName).isLoaded(controller.getDayString(year, month, day)))
controller.getCalendar(calendarName).summonDay(controller.getDayString(year, month, day));
if(controller.getCalendar(calendarName).isFree(3, controller.getDayString(year, month, day))) {
controller.getCalendar(calendarName).setFree(3, false, controller.getDayString(year, month, day));
buttonText = "Belegt";
intervallButtons[2].setToolTipText("Als Frei markieren");
}else {
controller.getCalendar(calendarName).setFree(3, true, controller.getDayString(year, month, day));
buttonText = "Frei";
intervallButtons[2].setToolTipText("Als Belegt markieren");
}
intervallButtons[2].setText(buttonText);
intervallButtons[2].setEnabled(false);
intervallButtons[2].setEnabled(true);
}else if (e.getSource() == intervallButtons[3]){
if(!controller.getCalendar(calendarName).isLoaded(controller.getDayString(year, month, day)))
controller.getCalendar(calendarName).summonDay(controller.getDayString(year, month, day));
if(controller.getCalendar(calendarName).isFree(4, controller.getDayString(year, month, day))) {
controller.getCalendar(calendarName).setFree(4, false, controller.getDayString(year, month, day));
buttonText = "Belegt";
intervallButtons[3].setToolTipText("Als Frei markieren");
}else {
controller.getCalendar(calendarName).setFree(4, true, controller.getDayString(year, month, day));
buttonText = "Frei";
intervallButtons[3].setToolTipText("Als Belegt markieren");
}
intervallButtons[3].setText(buttonText);
intervallButtons[3].setEnabled(false);
intervallButtons[3].setEnabled(true);
}else if (e.getSource() == intervallButtons[4]){
if(!controller.getCalendar(calendarName).isLoaded(controller.getDayString(year, month, day)))
controller.getCalendar(calendarName).summonDay(controller.getDayString(year, month, day));
if(controller.getCalendar(calendarName).isFree(5, controller.getDayString(year, month, day))) {
controller.getCalendar(calendarName).setFree(5, false, controller.getDayString(year, month, day));
buttonText = "Belegt";
intervallButtons[4].setToolTipText("Als Frei markieren");
}else {
controller.getCalendar(calendarName).setFree(5, true, controller.getDayString(year, month, day));
buttonText = "Frei";
intervallButtons[4].setToolTipText("Als Belegt markieren");
}
intervallButtons[4].setText(buttonText);
intervallButtons[4].setEnabled(false);
intervallButtons[4].setEnabled(true);
}else if (e.getSource() == intervallButtons[5]){
if(!controller.getCalendar(calendarName).isLoaded(controller.getDayString(year, month, day)))
controller.getCalendar(calendarName).summonDay(controller.getDayString(year, month, day));
if(controller.getCalendar(calendarName).isFree(6, controller.getDayString(year, month, day))) {
controller.getCalendar(calendarName).setFree(6, false, controller.getDayString(year, month, day));
buttonText = "Belegt";
intervallButtons[5].setToolTipText("Als Frei markieren");
}else {
controller.getCalendar(calendarName).setFree(6, true, controller.getDayString(year, month, day));
buttonText = "Frei";
intervallButtons[5].setToolTipText("Als Belegt markieren");
}
intervallButtons[5].setText(buttonText);
intervallButtons[5].setEnabled(false);
intervallButtons[5].setEnabled(true);
}else if (e.getSource() == intervallButtons[6]){
if(!controller.getCalendar(calendarName).isLoaded(controller.getDayString(year, month, day)))
controller.getCalendar(calendarName).summonDay(controller.getDayString(year, month, day));
if(controller.getCalendar(calendarName).isFree(7, controller.getDayString(year, month, day))) {
controller.getCalendar(calendarName).setFree(7, false, controller.getDayString(year, month, day));
buttonText = "Belegt";
intervallButtons[6].setToolTipText("Als Frei markieren");
}else {
controller.getCalendar(calendarName).setFree(7, true, controller.getDayString(year, month, day));
buttonText = "Frei";
intervallButtons[6].setToolTipText("Als Belegt markieren");
}
intervallButtons[6].setText(buttonText);
intervallButtons[5].setEnabled(false);
intervallButtons[5].setEnabled(true);
}else if (e.getSource() == intervallButtons[7]){
if(!controller.getCalendar(calendarName).isLoaded(controller.getDayString(year, month, day)))
controller.getCalendar(calendarName).summonDay(controller.getDayString(year, month, day));
if(controller.getCalendar(calendarName).isFree(8, controller.getDayString(year, month, day))) {
controller.getCalendar(calendarName).setFree(8, false, controller.getDayString(year, month, day));
buttonText = "Belegt";
intervallButtons[7].setToolTipText("Als Frei markieren");
}else {
controller.getCalendar(calendarName).setFree(8, true, controller.getDayString(year, month, day));
buttonText = "Frei";
intervallButtons[7].setToolTipText("Als Belegt markieren");
}
intervallButtons[7].setText(buttonText);
intervallButtons[7].setEnabled(false);
intervallButtons[7].setEnabled(true);
}else if (e.getSource() == intervallButtons[8]){
if(!controller.getCalendar(calendarName).isLoaded(controller.getDayString(year, month, day)))
controller.getCalendar(calendarName).summonDay(controller.getDayString(year, month, day));
if(controller.getCalendar(calendarName).isFree(9, controller.getDayString(year, month, day))) {
controller.getCalendar(calendarName).setFree(9, false, controller.getDayString(year, month, day));
buttonText = "Belegt";
intervallButtons[8].setToolTipText("Als Frei markieren");
}else {
controller.getCalendar(calendarName).setFree(9, true, controller.getDayString(year, month, day));
buttonText = "Frei";
intervallButtons[8].setToolTipText("Als Belegt markieren");
}
intervallButtons[8].setText(buttonText);
intervallButtons[8].setEnabled(false);
intervallButtons[8].setEnabled(true);
}else if (e.getSource() == intervallButtons[9]){
if(!controller.getCalendar(calendarName).isLoaded(controller.getDayString(year, month, day)))
controller.getCalendar(calendarName).summonDay(controller.getDayString(year, month, day));
if(controller.getCalendar(calendarName).isFree(10, controller.getDayString(year, month, day))) {
controller.getCalendar(calendarName).setFree(10, false, controller.getDayString(year, month, day));
buttonText = "Belegt";
intervallButtons[9].setToolTipText("Als Frei markieren");
}else {
controller.getCalendar(calendarName).setFree(10, true, controller.getDayString(year, month, day));
buttonText = "Frei";
intervallButtons[9].setToolTipText("Als Belegt markieren");
}
intervallButtons[9].setText(buttonText);
intervallButtons[9].setEnabled(false);
intervallButtons[9].setEnabled(true);
}else if (e.getSource() == intervallButtons[10]){
if(!controller.getCalendar(calendarName).isLoaded(controller.getDayString(year, month, day)))
controller.getCalendar(calendarName).summonDay(controller.getDayString(year, month, day));
if(controller.getCalendar(calendarName).isFree(11, controller.getDayString(year, month, day))) {
controller.getCalendar(calendarName).setFree(11, false, controller.getDayString(year, month, day));
buttonText = "Belegt";
intervallButtons[10].setToolTipText("Als Frei markieren");
}else {
controller.getCalendar(calendarName).setFree(11, true, controller.getDayString(year, month, day));
buttonText = "Frei";
intervallButtons[10].setToolTipText("Als Belegt markieren");
}
intervallButtons[10].setText(buttonText);
intervallButtons[10].setEnabled(false);
intervallButtons[10].setEnabled(true);
}else if (e.getSource() == intervallButtons[11]){
if(!controller.getCalendar(calendarName).isLoaded(controller.getDayString(year, month, day)))
controller.getCalendar(calendarName).summonDay(controller.getDayString(year, month, day));
if(controller.getCalendar(calendarName).isFree(12, controller.getDayString(year, month, day))) {
controller.getCalendar(calendarName).setFree(12, false, controller.getDayString(year, month, day));
buttonText = "Belegt";
intervallButtons[11].setToolTipText("Als Frei markieren");
}else {
controller.getCalendar(calendarName).setFree(12, true, controller.getDayString(year, month, day));
buttonText = "Frei";
intervallButtons[11].setToolTipText("Als Belegt markieren");
}
intervallButtons[11].setText(buttonText);
intervallButtons[11].setEnabled(false);
intervallButtons[11].setEnabled(true);
}
}
it's incredibly long and barely ajustable with just one variable, so all I want is following code standing in the creating for -loop:
if(!controller.getCalendar(calendarName).isLoaded(controller.getDayString(year, month, day)))
controller.getCalendar(calendarName).summonDay(controller.getDayString(year, month, day));
if(controller.getCalendar(calendarName).isFree(1, controller.getDayString(year, month, day))) {
controller.getCalendar(calendarName).setFree(i, false, controller.getDayString(year, month, day));
buttonText = "Belegt";
intervallButtons[i-1].setToolTipText("Als Frei markieren");
}else {
controller.getCalendar(calendarName).setFree(i, true, controller.getDayString(year, month, day));
buttonText = "Frei";
intervallButtons[i-1].setToolTipText("Als Belegt markieren");
}
intervallButtons[i-1].setText(buttonText);
intervallButtons[i-1].setEnabled(false);
intervallButtons[i-1].setEnabled(true);
but it doesn't work, because the actionListener can only handle non-local Variables... Do you have any ideas?
1 answers
solution1
1 ACCPTED 2020-06-28 14:24:50
and int i is different for every JButton, because it needs to be the int i from that for-loop.
One way is to set the "action command" for the button.
When you create the button you use:
JButton button = new JButton(...);
button.setActionCommand("" + i);
Then in the ActionListener you use:
int index = Integer.parseInt( event.getActionCommand() );
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