I have a JLabel that has keybinded actions on it. I have defined some code for some of the Actions but, alas, there are other JLabels, a JPanel, and other things within the method (this is in main()) that I want my Actions to fool with.
I tried to change the Actions into taking parameters, but was not successful, how can I get my actions to take in parameters to manipulate? Is there any way? I have looked about but this is pretty specific and I see few good examples.
Here is a nice slab of my code:
/*Bunch of stuff I want my actions to interact with above - another JLabel, a JPanel*/
ImageIcon cursor = new ImageIcon("cursor.gif");
JLabel cursorlbl = new JLabel("", cursor, JLabel.CENTER);
Action goRight = new AbstractAction() {
#Override
public void actionPerformed(ActionEvent arg0) {
System.out.println("lol");
}
};
Action goLeft = new AbstractAction() {
#Override
public void actionPerformed(ActionEvent arg0) {
System.out.println("lol2");
}
};
Action goUp = new AbstractAction() {
#Override
public void actionPerformed(ActionEvent arg0) {
}
};
Action goDown = new AbstractAction() {
#Override
public void actionPerformed(ActionEvent arg0) {
System.out.println("lol2");
}
};
cursorlbl.setFocusable(true);
cursorlbl.getInputMap().put(KeyStroke.getKeyStroke("RIGHT"),
"pressed right");
cursorlbl.getInputMap().put(KeyStroke.getKeyStroke("LEFT"),
"pressed left");
cursorlbl.getActionMap().put("pressed right", goRight);
cursorlbl.getActionMap().put("pressed left", goLeft);
You can declare each action as a subclass (this starts to separate MVC anyways), and each item you want to manipulate a field in the parent class. Example:
// Parent Class
public class ParentClass{
//Field you want to mess with in your action
JLabel cursorlbl = new JLabel("");
// Action that does things
public class MoveAction extends AbstractAction{
char direction;
//Constructor for action
public MoveAction(char direction){
this.direction = direction;
}
#Override
public void actionPerformed(ActionEvent arg0) {
int change = 0;
// Figure out how you'll be changing the variable
if(direction == 'u' || direction == 'r'){
change = 1;
} else{
change = -1;
}
// Apply the change to the correct variable
if(direction == 'u' || direction =='d'){
cursy += change;
} else{
cursx += change;
}
//Example how you can access the parent class's fields
cursorlbl.setLocation(cursx, cursy);
}
}
}
Then to set your actions, you just create instances of your subclass:
contentArea.getActionMap().put("pressed right", new MoveAction('r'));
contentArea.getActionMap().put("pressed left", new MoveAction('l'));
Declare other components you wish to see in your actions as final. That will make actions see them.
More info here
You should be able to pass them in like this:
// note that the JLabel is now final
final JLabel cursorlbl = new JLabel("", cursor, JLabel.CENTER);
Action goRight = new AbstractAction() {
#Override
public void actionPerformed(ActionEvent arg0) {
System.out.println(cursorlbl.getText()); // has access to JLabel because it's scoped to the method/class
}
};
Note that doing this can cause some maintenance issues and you should try to document things that might be unclear for future developers (and yourself two weeks from now!)
Related
I'm making a small game involving a grid of JButtons (MxN) and the main premise is to click on buttonA and then on buttonB, coloring buttonB and adjacent buttons of the same color as buttonB with the color of buttonA. I have made it so you are able to choose 3 possible difficulties. The colors are randomly generated. The main problem is getting the colors to change.
This is the method that I call after selecting the difficulty of the game:
public static void gameMechanics(int m, int n) {
final String[] pickedColour = {""};
final String[] placedColour = {""};
JButton[][] picked = new JButton[m][n];
JButton[][] placed = new JButton[m][n];
picked[m][n].addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
pickedColour[0] = picked[m][n].getText();
}
});
placed[m][n].addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
placedColour[0] = placed[m][n].getText();
}
});
if (pickedColour[0] == "R" && placedColour[0] != "R") {
placed[m][n].setBackground(Color.RED);
placed[m][n].setText("R");
}
else if (pickedColour[0] == "G" && placedColour[0] != "G") {
placed[m][n].setBackground(Color.GREEN);
placed[m][n].setText("G");
}
else if (pickedColour[0] == "B" && placedColour[0] != "B") {
placed[m][n].setBackground(Color.BLUE);
placed[m][n].setText("B");
}
}
I would consider using JPanels and painting them, using a MouseListener instead.
However, if you're set on using JButtons, try this:
button.setBackground(Color.GREEN);
button.setOpaque(true);
Note that this might not work if you're setting the look and feel using UIManager.
Also, you're doing a ton of extra work to map the color to the button - it could get confusing and cause errors down the road. Instead, you might try creating your own class:
class ColoredButton extends JButton {
private static final long serialVersionUID = 3040767030924461426L;
private Color color;
public ColoredButton(Color c) {
this.color = c;
this.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
changeColor();
}
});
}
public void changeColor() {
this.setBackground(this.color);
this.setOpaque(true);
}
}
Now, you can construct a new ColoredButton:
// Now, this button will turn green when clicked
ColoredButton temp = new ColoredButton(Color.GREEN);
I'd like to change value of my variable "name" when I select right button and click "ok" on my JRadio Frame.
For example when i select r1 and hit "ok" I'd like to have name=="Fast" in the entire package.
package Snake;
public class Radio extends JFrame {
private int delay = 100;
private String name;
JTextField t1;
JButton b;
JRadioButton r1, r2;
JLabel l;
public void selectSpeed() {
b = new JButton("Ok");
r1 = new JRadioButton("Fast");
r2 = new JRadioButton("Slow");
l = new JLabel("Speed: ");
ButtonGroup bg = new ButtonGroup();
bg.add(r1);
bg.add(r2);
add(b);
add(r1);
add(r2);
add(l);
b.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
if (r1.isSelected()) {
name = "Fast";
} else {
name = "Slow";
}
l.setText("Speed: " + name); // name=="Fast" when r1 is selected
} // name=="Slow" when r2 is selected
});
if (name == "Fast") { // and now name is empty...
delay = 50;
}
if (name == "Slow") {
delay = 500;
}
setLayout(new FlowLayout());
setSize(400, 400);
setVisible(true);
}
public int setSpeed() {
selectSpeed();
return delay;
}
}
If you want to change the delay on button click, You need to write the logic in the ActionListener itself because the code you have written to change the delay will run only once and that too at the start of the execution of your program and at that time, name will be empty.
Then when ever you click the button, It will only execute the ActionListener So delay will not be changed at any time. And other mistake you are making is that you are comparing Strings in wrong way. For more information take a look at it How do I compare Strings in Java?
To change delay dynamically on button click, you need to change it in the ActionListener.
b.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
if (r1.isSelected()) {
name = "Fast";
delay = 50;
} else {
name = "Slow";
delay = 500;
}
l.setText("Speed: " + name); // name=="Fast" when r1 is selected
} // name=="Slow" when r2 is selected
});
You need to do it in your JRadioButton listener. For example, like here, at first you change the variable "name" and later in the current listener you check conditions, but you need remember that to compare the strings you need to use "equals":
b.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
if (r1.isSelected()) {
name = "Fast";
} else {
name = "Slow";
}
l.setText("Speed: " + name); // name=="Fast" when r1 is selected
if (name.equals("Fast")) { // and now name is empty...
delay = 50;
}
if (name.equals("Slow")) {
delay = 500;
}
} // name=="Slow" when r2 is selected
});
Well I see my mistake now, Thank you.
But it still does not work the way I like. I'd like to change the "delay" value every time I select right button on JRadio and hit "ok" and with this changed value I'd like to go to the other class.
There is the code of a class where I need value of "delay":
package Snake;
public class Gameplay extends Paint implements KeyListener, ActionListener {
private Timer timer;
private int q = 0;
Radio radio = new Radio();
public Gameplay() {
addKeyListener(this);
setFocusable(true);
setFocusTraversalKeysEnabled(false);
timer = new Timer(radio.selectSpeed(), this); //here i need flexible "delay" value
timer.start();
}
I'm getting stuck while building a forum like application which has a vote button.
I have vote up and vote down button for each content which are automatically generated. I want this button to only display the up and down arrow but not any text or label.. how can i find out which button is pressed?
Automated content..
ImageIcon upvote = new ImageIcon(getClass().getResource("vote_up.png"));
ImageIcon downvote = new ImageIcon(getClass().getResource("vote_down.png"));
JButton vote_up = new JButton(upvote);
JButton vote_down = new JButton(downvote);
vote_up.addActionListener(voting);
vote_down.addActionListener(voting);
Action voting = new AbstractAction(){
#Override
public void actionPerformed(ActionEvent e){
//What to do here to find out which button is pressed?
}
};
any help is appreciated.
public void a(){
int crt_cnt = 0;
for(ClassA temp : listofClassA)
{
b(crt_cnt);
crt_cnt++;
}
}
public void b(crt_cnt){
//draw button
}
As from above, I have multiple vote_up and vote_down button created by the b function, how can i differentiate which crt_cnt is the button from?
There are multiple ways you might achieve this
You could...
Simply use the source of the ActionEvent
Action voting = new AbstractAction(){
#Override
public void actionPerformed(ActionEvent e){
if (e.getSource() == vote_up) {
//...
} else if (...) {
//...
}
}
};
This might be okay if you have a reference to the original buttons
You could...
Assign a actionCommand to each button
JButton vote_up = new JButton(upvote);
vote_up.setActionCommand("vote.up");
JButton vote_down = new JButton(downvote);
vote_down .setActionCommand("vote.down");
//...
Action voting = new AbstractAction(){
#Override
public void actionPerformed(ActionEvent e){
if ("vote.up".equals(e.getActionCommand())) {
//...
} else if (...) {
//...
}
}
};
You could...
Take full advantage of the Action API and make indiviual, self contained actions for each button...
public class VoteUpAction extends AbstractAction {
public VoteUpAction() {
putValue(SMALL_ICON, new ImageIcon(getClass().getResource("vote_up.png")));
}
#Override
public void actionPerformed(ActionEvent e) {
// Specific action for up vote
}
}
Then you could simply use
JButton vote_up = new JButton(new VoteUpAction());
//...
Which will configure the button according to the properties of the Action and will trigger it's actionPerformed method when the button is triggered. This way, you know 100% what you should/need to do when the actionPerformed method is called, without any doubts.
Have a closer look at How to Use Actions for more details
You can detect by using the method getSource() of your EventAction
Action voting = new AbstractAction(){
#Override
public void actionPerformed(ActionEvent e){
if (e.getSource() == vote_up ) {
// vote up clicked
} else if (e.getSource() == vote_down){
// vote down clicked
}
}
};
hey thanks for all the help and assistance! I've finally got it! I solved it by
assigning a text on the button, +/- for vote up or down, followed by the content id which i required, then change the font size to 0
vote.setText("+"+thistopic.content.get(crt_cnt).get_id());
vote.setFont(heading.getFont().deriveFont(0.0f));
after that i could easily trace which button is pressed by comparing to the
actionEvent.getActionCommand()
which return the text on the button!
I would wrap the JButton similar to this:
JButton createMyButton(final JPanel panel, final String text,
final boolean upOrDown, final int gridx, final int gridy) {
final JButton button = new JButton();
button.setPreferredSize(new Dimension(80, 50));
final GridBagConstraints gbc = Factories.createGridBagConstraints(gridx,
gridy);
panel.add(button, gbc);
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(final ActionEvent e) {
myActionPerformed(text, upOrDown);
}
});
return button;
}
You could use an int instead of the text, if more convenient.
Well its weird. I am not good with radiobuttons by the way. But I made a JPanel program in netbeans which includes a RadioButton. You enter all this information with JTextFields(no problem) and then lastly I had a JButton which you click the choice you want. Then I have a JButton that takes all the information and outputs this. For the RadioButton, I first entered the usual:
family = new JRadioButton("Family", true);
friend = new JRadioButton("Friend");
relative = new JRadioButton("Relative");
friendFriend = new JRadioButton("Friend of Friend");
ButtonGroup group = new ButtonGroup();
group.add (friend);
group.add (family);
group.add (relative);
group.add (friendFriend);
(I'm not sure if I needed a listner for the RadioButtons or not but my program still seems to "crash" no matter what).
then I had one action listner for the JButton which included all the textfields and radio buttons. But the RadioButton is the issue.
In the action listner I had:
Object source = event.getSource();
if (source == family)
relation1 = true;
else
if (source == friend)
relation2 = true;
else
if(source == relative)
relation3 = true;
else
if(source == friendFriend)
relation4 = true;
Then I made a relation class:
public class Relation {
private boolean arrayFamily, arrayFriend, arrayRelative, arrayFriendFriend;
public Relation(boolean relation1, boolean relation2, boolean relation3,
boolean relation4)
{
this.arrayFamily = relation1;
this.arrayFriend = relation2;
this.arrayRelative = relation3;
this.arrayFriendFriend = relation4;
}
public String relations ()
{
String relationship = null;
if(arrayFamily && !arrayFriend && !arrayRelative && !arrayFriendFriend == true)
{
relationship = "Family";
}
else
if(arrayFriend && !arrayFamily && !arrayRelative &&
!arrayFriendFriend == true)
{
relationship = "Friend";
}
else
if(arrayRelative && !arrayFamily && !arrayFriend &&
!arrayFriendFriend == true)
{
relationship = "Relative";
}
else
if(arrayFriendFriend && !arrayFamily && !arrayFriend &&
!arrayRelative == true)
{
relationship = "Friend of a Friend";
}
return relationship;
}
}
LASTLY back in the action listner, I implementer this class:
Relation relationship = new Relation(relation1, relation2, relation3
, relation4);
String arrayRelation = relationship.relations();
I lastly included arrayRelation in an array but the array worked fine.
My problem is that the output of the array for my RadioButtons keeps reading "null" (most likey because this code: String relationship = null;). I assume this means that none of my if else statements were satisfied and I really dont know why.
Also important to point out is that if I click submit without clicking any radio button (the button stays on "family"), it reads null. If I click a button once it works perfectly reading the string I intended. But if I click another button afterwards and click submit again, the string goes back to "null".
I know its lengthy but I would really appreciate any help because I am lost.
P.S. some parts of my code are repetitive because I was playing around trying to fix the problem.
I suggest you handle your action events separately, for example:
family.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
familyActionPerformed(evt);
}
});
Then implement familyActionPerformed(evt):
private void familyActionPerformed(java.awt.event.ActionEvent evt) {
// every click on family radio button causes the code here to be executed
relation1 = true;
}
Also write an event handler for the button you click, like this:
submitButtonActionPerformed(java.awt.event.ActionEvent evt) {
// Here test the state of each radio button
relation1 = family.isSelected();
relation2 = friend.isSelected();
relation3 = relative.isSelected();
relation4 = friendFriend.isSelected();
}
MORE EDIT:
Doing what you're doing with NetBeans should be very easy. Here are tutorials that will clear it all up for you:
Tutorial 1
Tutorial 2
I explain the solution again:
Using 'family' button as an example, in your constructor where you have created and initialised your GUI components do this:
JRadioButton family = new JRadioButton();
// do any other thing you want to do to this button and finally..
family.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
familyActionPerformed(evt);
}
});
JButton submit = new JButton("Submit");
submit.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
submitActionPerformed(evt);
}
});
Then somewhere create these methods:
private void familyActionPerformed(java.awt.event.ActionEvent evt){
// each time family is selected, you code processes the lines below:
...
}
private void submiteActionPerformed(java.awt.event.ActionEvent evt){
relation1 = family.isSelected();
relation2 = friend.isSelected();
relation3 = relative.isSelected();
relation4 = friendFriend.isSelected();
}
Do something similar for the rest of the RadioButtons.
I think that you're making things way too complex for yourself. If all you want is the String of the JRadioButton pressed, then use the ButtonGroup to get it for you. It can return the ButtonModel of the selected JRadioButton (if any one was selected), and from that you can extract the actionCommand String, although you'll have to remember to set this when you create your JRadioButton.
For example:
import java.awt.event.ActionEvent;
import javax.swing.*;
#SuppressWarnings("serial")
public class JRadioExample extends JPanel {
private static final String[] RADIO_TITLES = { "Family", "Friend",
"Relative", "Friend or Relative" };
private ButtonGroup btnGrp = new ButtonGroup();
public JRadioExample() {
for (int i = 0; i < RADIO_TITLES.length; i++) {
JRadioButton rBtn = new JRadioButton(RADIO_TITLES[i]);
rBtn.setActionCommand(RADIO_TITLES[i]); // ***** this is what needs to
// be set
btnGrp.add(rBtn);
add(rBtn);
}
add(new JButton(new BtnAction("Get Chosen Selection")));
}
private class BtnAction extends AbstractAction {
public BtnAction(String name) {
super(name);
}
#Override
public void actionPerformed(ActionEvent evt) {
ButtonModel model = btnGrp.getSelection();
if (model != null) {
String actionCommand = model.getActionCommand();
System.out.println("Selected Button: " + actionCommand);
} else {
System.out.println("No Button Selected");
}
}
}
private static void createAndShowGui() {
JRadioExample mainPanel = new JRadioExample();
JFrame frame = new JFrame("JRadioExample");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
I have created a key binding for a JTextArea Component. When invoked, it creates a new instance of itself and sets focus to it.
If you hold down the enter (which invokes key binding) my program will start spitting out bunch of JTextArea instances.
Is there a way to force the user to press enter againg to create a new instance?
Do I have I switch to KeyListeners or is there a way with key bindings?
You specify that a KeyStroke only fire on key release when you're setting up the input map
See KeyStroke getKeyStroke(int keyCode, int modifiers, boolean onKeyRelease)
the way to do it with keybindings is to have two actions:
an action creating the component is bound to the pressed enter, it disables itself when inserting the component
an action enabling the action again is bound to the released enter
Some code:
// the action to create the component
public static class CreateAction extends AbstractAction {
private Container parent;
private Action enableAction;
public CreateAction(Container parent) {
this.parent = parent;
enableAction = new EnableAction(this);
}
#Override
public void actionPerformed(ActionEvent e) {
setEnabled(false);
Component field = createTextField();
parent.add(field);
parent.revalidate();
field.requestFocus();
}
int count;
private Component createTextField() {
// just for fun counting the fields we create
JTextField field = new JTextField("field: " + count++, 20);
field.getInputMap().put(KeyStroke.getKeyStroke("ENTER"),
"createComponent");
field.getActionMap().put("createComponent", this);
field.getInputMap().put(KeyStroke.getKeyStroke("released ENTER"),
"enableCreation");
field.getActionMap().put("enableCreation", enableAction);
return field;
}
}
// the action that enables another
public static class EnableAction extends AbstractAction {
Action toEnable;
public EnableAction(Action toEnable) {
this.toEnable = toEnable;
}
#Override
public void actionPerformed(ActionEvent e) {
toEnable.setEnabled(true);
}
}
// usage
final JComponent parent = new JPanel(new MigLayout("wrap"));
// here I'm lazy and let the action create the very first component as well
add.actionPerformed(null);
add.setEnabled(true);
Note that the same instances of the actions are registered to all components, so it doesn't matter which has the focus (and ultimately enables the creation again)
Here is the code I use, to have an action only run when a key is first pressed down:
private void registerKeyBindings(final JFrame frame) {
var inputMap = frame.getRootPane().getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW);
inputMap.put(KeyStroke.getKeyStroke(KeyCode.G.getInputEventCode(), 0, false), "g_down");
inputMap.put(KeyStroke.getKeyStroke(KeyCode.G.getInputEventCode(), 0, true), "g_up");
frame.getRootPane().getActionMap().put("g_down", new AbstractAction() {
#Override public void actionPerformed(ActionEvent e) {
if (gDown) return;
gDown = true;
// put your custom key-down-action code here
}
});
frame.getRootPane().getActionMap().put("g_up", new AbstractAction() {
#Override public void actionPerformed(ActionEvent e) {
gDown = false;
}
});
}
Boolean gDown = false;