I am making a program where clicking a custom JButton allows you to make your next click paint an image at the point on the screen. Members of this JButton class have certain data that is unique to each separate button. My question is if I can pass the JButton object when clicked on through a method into a class which would then extract the data. I was thinking something like this:
Click Method in JButton{
OutsideClass.setObject(this); //problem
}
OutsideClass{
Object obj = new Object();
public void setObject(Object Obj){
obj = Obj;
}
Click Method in OutsideClass{
place obj;
obj.getData;//Methods within JButton that retrieve specific data
}
My issue is the "setObject" part of the JButton. It doesn't recognize "this" as the specific Object clicked and thus doesn't work. Is there another way to get the desired effect? Thanks!
Related
Is there a method to get the button associated with a particular command string?
For instance if I define a button with:
button.setActionCommand("unique_toggle");
Having that string "unique_toggle", is it possible to retrieve that button from another class? I am beginner at Java, excuse if this question may seem obvious to you.
Yes, you can access to your button and its associated button's command. If you need to a button's command, that possibly means that you should consider redesining your programm because this approach is not advisable and very dirty way to do what you want to achieve.
When it comes to answer to your question,
Lets say Foo1 is your GUI class.
class Foo1{
JButton button;
public Foo1(Foo2 otherClass)
{
button = new JButton();
otherClass.setButtonAddress(button);
}
..... other methods
}
Foo2 is the class, in where you want to access button's command text.
class Foo2{
JButton buttonFromOtherClass;
//This is the method, in where you need command string of the button
private void getCommandsString()
{
Foo1 foo1 = new Foo1(this);
//After the initialization of Foo1, you can get every information of the button
String actionCommand = buttonFromOtherClass.getActionCommand();
}
public void setButtonAddress(JButton button)
{
buttonFromOtherClass = button;
}
}
I have a quick question. I don't get it...
I've got a JFrame where I add a JComboBox:
JComboBox<String> Team_ComboBox = new JComboBox<>();
Team_ComboBox_Handler ComboBox_Listener = new Team_ComboBox_Handler();
Team_ComboBox.addActionListener(ComboBox_Listener);
Team_ComboBox.addItem("Test 1");
Team_ComboBox.addItem("Test 2");
On this Frame I have a button which opens another JFrame.
Play = new JButton();
Play.setText("Play");
Play.setPreferredSize(dimension);
Play.addActionListener(menuhandler);
private class main_menuhandler implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
if(e.getSource()==Play){
teams Team = new teams();
Team.teams();
disposeMainMenue();
}
if(e.getSource()==Close) {
System.exit(DO_NOTHING_ON_CLOSE);
}
}
}
Anyway, I would like to transfer the Selected value of the Combobox to a method of the other class. I know how I can get the itemvalue of the combobox in the method itself (with getselecteditem) But how can I do that in the ActionPerformed Method as I can't access the combobox in the ActionPerformed method.... I created another ActionListener (comboBox_Listener) but I haven't put any code into it...
Any idea? Thanks a lot in advance
Several issues appear to me:
Your main question:
But how can I do that in the ActionPerformed Method as I can't access the combobox in the ActionPerformed method
Your likely best solution is to change your code and variable declaration placement so that you can access the JComboBox fromt he actionPerformed method. If you're declaring the combobox from within a method or constructor, change this so that it is a proper instance field of the class.
Other problems:
You should not be creating multiple JFrames. If you need a dependent window, then one should be a JDialog. If not, then consider swapping views with a CardLayout.
Learn and follow Java naming conventnions so others can better understand your code. Class names begin with capital letters and methods and variable names don't for instance.
I am not sure why you're doing this: System.exit(DO_NOTHING_ON_CLOSE);. Why pass that constant into the exit method?
Use a constructor for your action listener class:
private class main_menuhandler implements ActionListener {
private JComboBox<String> Team_ComboBox;
public main_menuhandler(JComboBox<String> Team_ComboBox){
this.Team_ComboBox = Team_ComboBox;
}
}
Now you can create the class main_menuhandlervia the constructor and add the combobox to it.
In your Overriden action you have access to it.
Try playing around with this as your code snippet isn't broad enough to actually provide proper code. But this should answer your question
Lets say i have an array of 100 employees. Each employee in the array, is an instance of the class Employee, that have many attributes, such as name, direction, salary, etc.
I want to display, 1 button for each employee in the array, and when you click one, you get the information of that employee.
What i don't know, is how can i link a button to an specific employee. I Was thinking on, somehow, attaching an Integer variable to the button, so i know which employee is related to that specific button, but, i don't really know how to do that.
Anyone cares to give me some advice on this?
You could use setName(employeeId) method for JButton to set Employee's id or use putClientProperty("id", employeeId), when you get a callback at button's listener you could get the name or your property.
You can use the putClientProperty and getClientProperty to attach any object to a JComponent.
If you get "this" inside listener you get a reference to listener's object. You should use getSource() method, like:
JButton j = new JButton("click here");
j.putClientProperty("id", "employee1");
j.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent ae) {
JButton source = (JButton)ae.getSource();
String id = (String) source.getClientProperty("id");
System.out.print(id);
}
});
Will print - employee1.
I have 2 classes, one class is a datamodel class and the other is a gui class.
class datamodel .........
Takes user selected data and creates a arraylist
class gui .........
Has a tableviewer that is using the array from the datamodel class
My issue is I need to fresh the tableviewer when the user has added more data to the array.
I created a updateTableViewer method in the gui class.
public void updateTableViewer() {
if(getViewer() != null) {
viewer.refresh();
{
Then I made a reference to the gui class in the datamodel class.
AplotBaseDialog abd = new AplotBaseDialog(null, null);
Then I added the method call to the method adding more data to the array
public void add(TCComponentItemRevision tcRevision, TCComponentDataset selectedDataset) {
AplotDatasetData pp = new AplotDatasetData(tcRevision, selectedDataset);
if (!dataArrayList.contains(pp)) {
dataArrayList.add(pp);
}
abd.updateTableViewer();
}// end add()
This does not work. The getViewer() call always returns null, even if the gui class is created and open.
So I create a boolean value;
Boolean hasViewerBeenCreated = false;
I am setting the value to true after the tableviewer is created.
viewer = new AplotDataTableViewer(parent, SWT.BORDER|SWT.V_SCROLL|SWT.FULL_SELECTION);
viewer.setInput(AplotDataModel.getInstance().getArrayData());
hasViewerBeenCreated = true;
Then I created a method to return the boolean value.
I am calling the method from a button on the dailog.
I also replaced the updateTableViewer method call in the datamodel class
if (!dataArrayList.contains(pp)) {
dataArrayList.add(pp);
}
abd.getBooleanValue();
}
Here are the results.
I execute the add method in the datamodel class -
It returns false - That makes sense because the dailog has not been created at this time
I execute and create the gui class
I click the button and it returns true - This makes sense because the viewer has been created
Here is where I get confused.
With the gui still open, I can execute the add method again and it stills returns a false value. Then I can click the button and see it is true value.
I would think that when the gui is created and the boolean value is set to true. I would be able to get the current value of the boolean in other classes.
I am not sure if I am not referencing the gui class correctly or when the gui is created I am not accessing the current thread or tableviewer?
I don't know if this is a thread issue or I am just not getting the current value from the gui correctly.
This is a big issue with my application right now. I have to be able to refresh the tableviewer any time new data is added to the array. I can not have the user having to manually refresh the table every time that select new data
I've problem regarding GUI with one Menu and one Order Class.
I've created a variable to store how many items have been selected in the Menu Class.
private int totalSelected;
The var totalSelected is live updated. It can be changed anytime depending on actionPerformed() function.(Exp: totalSelected will add up all the selected items)
In the Order Class, how can I access to the live update variable totalSelected in order to retrieve the live update value? When I invoke getTotalSelected() function inside the Menu Class, I will only obtain a 0 value.
Thanks for your help ^^!
Please allow me to specify my question clearer.
public class MenuTab extends JPanel
{
private JLabel display;
private int totalSelected;
public MenuTab()
{
....
}
}
public getTotalSelected(){
return totalSelected;
}
private class SelectedListener implements ActionListener
{
public void actionPerformed()
{
.......
//Assume that totalSelected has been updated!
display = new JLabel("Total: " + totalSelected);
// OK to display totalSelected live value here.
}
}
// A new class is the confirmation of order
public class OrderConfirmedTab extends JPanel{
private JLabel displayTotal;
private MenuTab order = new MenuTab();
public OrderConfirmedTab()
{
......
int totalSelected = order.getTotalSelected();
displayTotal = new JLabel("Total: " + totalSelected);
// Problem to display totalSelected live value here.
// Will obtain 0;
// How can I obtain the live updated value from class MenuTab? Thanks!
}
}
If I read your code right, you need to make your variable be private static int totalSelected; You need to make it static so that it stays the same for all instances of the class.
I looks like your not updating the private int totalSelected; variable when a user makes a selection, so it is always 0.
Ya! I just realized that my JLabel
will not update the value
automatically. So how can I fix it?
Thanks! – Christine
If I understand you correctly you have two GUIs where changes in one (the MenuTab) will update the other (OrderConfirmedTab) in real time?
If so, you will need to increase the coupling between the two objects. If MenuTab has a reference back to OrderConfirmedTab then it can call methods to update the value as it changes.
For example, pass OrderConfirmedTab into MenuTabs constructor
MenuTab mt = new MenuTab(this); // from within OrderConfirmTabs costructor
Then when MenuTab has an actionPerformed event it can call back to OrderConfirmTab
orderConfirmTab.setTotalSelected(totalSelected); // you have to create this method in OrderConfirmTab
I hope this helps a little
You can use PropertyChangeListener and PropertyChangeSupport mechanisms to dispatch an event when the value is updated and to be notified when the variable has changed. Your JLabel is not going to update on its own; even if you were to use an object other than a primitive (note that primitives are merely values, while objects are actually implicit pointers); you will need to update your JLabel when the variable changes, since the JLabel simply stores a string, not a reference to the variables from which the string was constructed.
This is the concept of model-view-controller; your variable should be in some sort of class or classes that represent the model (the information) and which allow changes to be observed via property change events. Your view classes should simply provide display logic and no business or application-specific logic. It is the controller in which your application logic should reside; your controller should register for events on the model, and it should update the view whenever the model has changed, and it should likewise update the model when the view dispatches events that should result in the model being changed.