I usually write the code in C#, and I even have the application finished in C#, but I need to port it to Java.
Just started out today, never really used Java before.
The problem is quite strange because I do not get any error it just does not update, here's the code:
public void setInfoStrip(String infoStrip) {
InfoStrip.setText(infoStrip);
}
The above is a Setter that should update the JTextField (and it does if I update it using the ActionListener for a button), but it does not update the text when I call it in a class or even in the main(String[] args) entry point of application using this code:
mainGUI GUI = new mainGUI();
GUI.setInfoStrip("test");
or this code:
new mainGUI().setInfoStrip("test");
My guess is that it does nothing becuase I call it from a static class
public static void main(String[] args)
But even if I create a new class that's not static and reference it from the public staitc void main(String[] args) then put either
mainGUI GUI = new mainGUI();
GUI.setInfoStrip("test");
or
new mainGUI().setInfoStrip("test");
It the newly created class, which I call by
new ImGoingToCry().Alot();
It still does nothing.
I'm confused as hell, I even read some problems connected with this on google but they were all solved by this:
mainGUI GUI = new mainGUI();
GUI.setInfoStrip("test");
Here's the MVCE that some of you requested:
public class mainGUI {
// GUI Elements
private JPanel WorkSpace;
private JTabbedPane tabbedPane1;
private JList DetectedProfiles;
private JButton StartGame;
private JTextField CurProf;
private JButton BackupProfiles;
private JButton SearchSaves;
private JButton RetrieveProfiles;
private JTextField InfoStrip;
private JLabel ProfileSize;
/**
* Getter and Setter functions
*/
public void setInfoStrip(String infoStrip) {
InfoStrip.setText(infoStrip);
}
// Initialize the main application GUI and set it's properties
public static void main(String[] args) {
JFrame mainGUIFrame = new JFrame("The Witcher 3 Save Manager | " + " ver. " + GlobalVariables.appversion);
mainGUIFrame.setContentPane(new mainGUI().WorkSpace);
mainGUIFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
mainGUIFrame.setLocationRelativeTo(null);
mainGUIFrame.setPreferredSize(new Dimension(420, 370));
mainGUIFrame.setResizable(false);
mainGUIFrame.pack();
mainGUIFrame.setVisible(true);
new mainGUI().run();
}
public void run() {
/**
* Initialize the core application functions
*/
// Load the application settings
GlobalVariables.Settings();
// Initialize the app components
GlobalVariables.Initialize();
// Pass the value to setter
new mainGUI().setInfoStrip("test"); // This should change the text but it does nothing there's not even an error
}
}
May be this will be of help. From javadocs for JTextComponent, from which JTextField inherits setText() method:
setText
Sets the text of this TextComponent to the specified text. If the text is null or empty, has the effect of simply deleting the old text. When text has been inserted, the resulting caret location is determined by the implementation of the caret class.
Note that text is not a bound property, so no PropertyChangeEvent is fired when it changes. To listen for changes to the text, use DocumentListener.
In case you wonder what a BoundProperty is:
A bound property notifies listeners when its value changes. This has
two implications:
The bean class includes addPropertyChangeListener() and
removePropertyChangeListener() methods for managing the bean's
listeners.
When a bound property is changed, the bean sends a
PropertyChangeEvent to its registered listeners. PropertyChangeEvent
and PropertyChangeListener live in the java.beans package.
The java.beans package also includes a class, PropertyChangeSupport,
that takes care of most of the work of bound properties. This handy
class keeps track of property listeners and includes a convenience
method that fires property change events to all registered listeners.
P.S.: as the OP has not given any mcve, this sounds relevant. But, I strongly feel the case is going to be otherwise once we see the OP's code.
Related
What I want to achieve is very simple.
I have 2 classes. "SpeedingTicket" & "SpeedingTicket GUI".
Inside my GUI I have 1 textbox name txtSpeedLimit & a button.
Inside my SpeedingTicket class I have a variable "int speedingTicket".
Inside my SpeedingTicket class I also have a get & set method for "speedingTicket".
I know how to get and set text using JTextFields, but I want to be able to:
receive input from the "txtSpeedLimit", and store that value into the "txtSpeedLimit" instance variable in the "SpeedTicket" class. I can then check for validation etc when I come to adding the vehicle speed.
Maybe this isn't the most efficient way of dealing with this program. Maybe I should scrap the instance variables in SpeedingTicket, and deal with it all in the GUI.
Any advice would be hugely appreciated.
Basically what I'm trying to do is this:
class confirmHandler implements ActionListener{
public void actionPerformed(ActionEvent e){
String val = txtSpeedLimit.getText();
int realNum = speed.getSpeedLimit() = txtSpeedLimit; < but obviously that doesn't work, but I want the textbox link to the variable.
EDIT: If we take away the GUI, all I want my program to do is the following:
Speed Limit: 50 < enterd via textfield
Speed: 60 < entered via textfield
if the speed is blah blah (ive already coded this).. then output a result to one of my labels.
I achieved this without making a GUI and making it only console based, but instead of the user typing it via the console, I want it to be typed via textfields.
THe values that are entered into the textfields should be stored in the two variables (speed and speedlimit) that are in the SpeedingTicket class.
You can update a value in:
public class SpeedingTicket {
int speedingTicket;
public SpeedingTicket() {
speedingTicket = 500;
}
public int getSpeedingTicket() {
return speedingTicket;
}
}
by:
public class SpeedingTicketGUI extends JPanel{
SpeedingTicket st;
SpeedingTicketGUI() {
st = new SpeedingTicket();
setLayout(new FlowLayout(FlowLayout.LEFT));
JTextField txtField = new JTextField(10);
txtField.setText(""+st.getSpeedingTicket());
add(txtField);
JButton btn = new JButton("Update");
btn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
setSpeedingTicket(txtField.getText());
}
});
add(btn);
}
private void setSpeedingTicket(String text) {
try {
int speedTicket = Integer.parseInt(text);
st.setSpeedingTicket(speedTicket);
System.out.println("Speeding ticket set to " +st.getSpeedingTicket());
} catch (NumberFormatException ex) {
System.out.println("Invalid value " +text);
ex.printStackTrace();
}
}
public static void main(String[] args){
JFrame frame = new JFrame("Speeding Ticket");
frame.setSize(400,100);
frame.add(new SpeedingTicketGUI());
frame.setVisible(true);
}
}
You don't need to store values in JText or any GUI componenets...
Use global static variables. For example:
public static int speed_limit;
You can access this variable from ANY method,class, etc.
There are multiple ways to do it.
You can detect textfield changes by using a DocumentListener or if you want (not recommended) by a KeyListener.
The Listener could be implemented directly by your gui class or by your other class. If you want more abstraction you could implement the DocumentListener by your gui class and create a method
public void addSpeedChangeListener(SpeedChangeListener scl) {
this.speedChangeListeners.add(scl);
}
Your SpeedChangeListener could be very simple:
public interface SpeedChangeListener {
public void speedChanged(int value);
}
Then your second class implements the SpeedChangeListener and calls addSpeedChangeListener(this) on your gui class. Inside the gui class, your document listener calls speedChanged(val) for every listener registered.
EDIT
You can also use the Button and call the speedChanged on every listener inside the actionPerformed method of the ActionListener.
I think it would be easier to use a JOptionDialog which pop ups when the button is clicked. That way you can easily get input and also validate the input straight away.
I currently have all my action listeners declared under my constructor, but I'm starting to get a lot of them building up. Is it possible to create a new classes (via the default package window) and have them all there separately?
This seems obvious to me, I have tried this and I get no errors, but my application wont load when I do, it says its open but theres nothing there.
Here is a link to my code that is compilable.. I have commented out anything that uses other classes (there isn't much), if I have missed any just comment them out.
https://shrib.com/Tum8kjgH?v=nc
Thanks!
The most simple solution is to declare your listeners each in their own class. For example, for some button:
public class SomeButtonActionListener implements ActionListener{
private InternalFrame iFrame;
public SomeActionListener(InternalFrame iFrame){
this.iFrame = iFrame;
}
public void actionPerformed(ActionEvent ae) {
//TODO
//Example: iFrame.getSomeButton().doSomething();
}
}
Note that in this way, you need to expose getter methods for all swing components you need to access from your listeners (an alternative is to send the specific components needed as arguments to the listener when constructor is called).
In your InternalFrame you can add the listeners as:
someButton.addActionListener(new SomeButtonActionListener(this));
Also you can put all your listeners in a specific package like yourapp.listeners.
EDIT
A more specific example:
public class AddRoomListener implements ActionListener{
private InternalFrame iFrame;
public AddRoomListener(InternalFrame iFrame){
this.iFrame = iFrame;
}
public void actionPerformed(ActionEvent event) {
iFrame.getIntFrame2().setVisible(true);
iFrame.getIntFrame2().toFront();
}
}
In this case you need to declare the getIntFrame2() getter in the InternalFrame class.
Below program will create 2 simple windows where we can type some text, and it will be shown in both windows' display screen.
I created a Class to generate UI. However, when I use the same class to create 2 objects (typeWriterObj1 & typeWriterObj2) and click on btnSend.
The typed in message are always directed and displayed in the last created window (For example: I type text into Alice's txtMessage and click btnSend, text is shown in Bob's window instead of Alice's).
See below example:
public class TextProgram
{
public static void main(String[] args)
{
TypeWriterUI typeWriterObj1 = new TypeWriterUI();
TypeWriterUI typeWriterObj2 = new TypeWriterUI();
TypeWriterObj1.showGUI("Alice");
TypeWriterObj2.showGUI("Bob");
}
}
class TypeWriterUI extends JPanel
{
static JButton btnSend;
static JTextArea txtDisplay = new JTextArea();
static JTextArea txtMessage = new JTextArea();
//...Codes which add the swing components
//ActionListerner for btnSend which transfer input text from txtMessage to txtDisplay
}
Que: How can this problem be resolved if I were not to use multi-threading?
Undo making the fields static (one instance per class). Both GUIs shared every button instance. That this worked is even a miracle; probably twice assigned a new JButton to the same variable and so on.
I'm new to Java and I've hit a brick wall. I want to access GUI components (that have been created in one class) from another class. I am creating a new GUI class from one class, like so;
GUI gui = new GUI();
and I can access the components in that class, but when I go to a different class I cant. I really just need to access the JTextAreas to update their content. Could someone point me in the right direction please, any help is greatly appreciated.
GUI Class:
public class GUI {
JFrame frame = new JFrame("Server");
...
JTextArea textAreaClients = new JTextArea(20, 1);
JTextArea textAreaEvents = new JTextArea(8, 1);
public GUI()
{
frame.setLayout(new FlowLayout(FlowLayout.LEADING, 5, 3));
...
frame.setVisible(true);
}
}
First respect encapsulation rules. Make your fields private. Next you want to have getters for the fields you need to access.
public class GUI {
private JTextField field = new JTextField();
public GUI() {
// pass this instance of GUI to other class
SomeListener listener = new SomeListener(GUI.this);
}
public JTextField getTextField() {
return field;
}
}
Then you'll want to pass your GUI to whatever class needs to access the text field. Say an ActionListener class. Use constructor injection (or "pass reference") for the passing of the GUI class. When you do this, the GUI being referenced in the SomeListener is the same one, and you don't ever create a new one (which will not reference the same instance you need).
public class SomeListener implements ActionListener {
private GUI gui;
private JTextField field;
public SomeListener(GUI gui) {
this.gui = gui;
this.field = gui.getTextField();
}
}
Though the above may work, it may be unnecesary. First think about what exactly it is you want to do with the text field. If some some action that can be performed in the GUI class, but you just need to access something in the class to perform it, you could just implement an interface with a method that needs to perform something. Something like this
public interface Performable {
public void someMethod();
}
public class GUI implements Performable {
private JTextField field = ..
public GUI() {
SomeListener listener = new SomeListener(GUI.this);
}
#Override
public void someMethod() {
field.setText("Hello");
}
}
public class SomeListener implements ActionListener {
private Performable perf;
public SomeListener(Performable perf) {
this.perf = perf;
}
#Override
public void actionPerformed(ActionEvent e) {
perf.someMethod();
}
}
Several approaches are possible:
The identifier gui is a reference to your GUI instance. You can pass gui to whatever class needs it, as long as you respect the event dispatch thread. Add public accessor methods to GUI as required.
Declarations such as JTextArea textAreaClients have package-private accessibility. They can be referenced form other classes in the same package.
Arrange for your text areas to receive events from another class using a PropertyChangeListener, as shown here.
The best option to access that text areas is creating a get method for them. Something like this:
public JTextArea getTextAreaClients(){
return this.textAreaClients;
}
And the same for the other one.So to access it from another class:
GUI gui = new GUI();
gui.getTextAreaClients();
Anyway you will need a reference for the gui object at any class in which you want to use it, or a reference of an object from the class in which you create it.
EDIT ---------------------------------------
To get the text area from GUI to Server you could do something like this inside of Create-Server.
GUI gui = new GUI();
Server server = new Server();
server.setTextAreaClients(gui.getTextAreaClients());
For this you should include a JTextArea field inside of Server and the setTextAreaClients method that will look like this:
JTextArea clients;
public void setTextAreaClients(JTextArea clients){
this.clients = clients;
}
So in this way you will have a reference to the JTextArea from gui.
here i add a simple solution hope it works good,
Form A
controls
Textfield : txtusername
FormB fb = new FormB();
fb.loginreset(txtusername); //only textfield name no other attributes
Form B
to access FormA's control
public void ResetTextbox(JTextField jf)
{
jf.setText(null); // or you can set or get any text
}
There is actually no need to use a class that implements ActionListener.
It works without, what might be easier to implement:
public class SomeActionListener {
private Gui gui;
private JButton button1;
public SomeActionListener(Gui gui){
this.gui = gui;
this.button1 = gui.getButton();
this.button1.addActionListener(l -> System.out.println("one"));
}
}
and then, like others have elaborated before me in this topic:
public class GUI {
private JButton button = new JButton();
public GUI() {
// pass this instance of GUI to other class
SomeActionListener listener = new SomeActionListener(GUI.this);
}
public JButton getButton() {
return button;
}
}
I can't .setText(...) for a JTextField outside of the class that creates the gui. I'm very confused and I feel like there is something basic I am missing. I need some help here.
Here is what I am doing:
In a class (called MainClass) I create an instance of a class that creates my gui
TestText gui = new TestText();
with a constructor that sets the default settings (a JTextField and a button with a listener). Then I call the a setter that I wrote, where I pass it a string that is to set the text of the JTextField:
gui.setText("new");
But "new" doesn't show up on the gui.
I know my setter works from within the class because if I make a call to the setter from the button that I created in gui then the changes show up on the gui.
The part that really confuses me is this: If I call my getter just before my setter, then it returns the old value. Then if I call the getter again after I call the setter then it returns the new value, while the gui continues to show the old value. I thought that maybe it just isn't repainting the gui so I tried all kinds of permutations of .invalidate(), .validate(), .update() and .repaint(), all from the MainClass and from inside the setter. But none did anything.
Is it possible that I somehow have 2 different instances of the gui and I'm only editing one of them?
import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class TestText {
private JTextField textField;
private JButton button;
private JPanel frame;
JFrame jFrame;
public void setText(String text) {
textField.setText(text);
}
public String getText() {
return textField.getText();
}
public TestText() {
this.textField.setText("98.6");
this.jFrame = new JFrame("TestText");
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
setText("new (button)");
}
});
}
public void setData(TestText data) {
data.setText("new (setData)");
}
public void getData(TestText data) {
}
public boolean isModified(TestText data) {
return false;
}
public void createGui(String[] args) {
jFrame.setContentPane(new TestText().frame);
jFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jFrame.pack();
jFrame.setVisible(true);
}
}
and then here's the main class that I'm trying to create the gui from:
public class MainClass {
public static void main(String[] args) {
TestText gui = new TestText();
gui.createGui(null);
System.out.println(gui.getText());
gui.setData(gui);
System.out.println(gui.getText());
gui.setText("new (MainClass)");
System.out.println(gui.getText());
}
}
It looks like you're missing the reference to the text field I think...
gui.referenceToTextField.setText("new word");
EDIT: Very nice SSCCE! However, there are several problems (not in the order provided, necessarily).
You are overriding the setText() method. Don't do this unless you want the method to do something different—why you would want to do this I have no idea.
You aren't even using the args array in the createGui() method. You can create methods without specifying any parameters/arguments.
The getData() method is, right now, useless (If I were you, given what you're trying to accomplish, I would remove the method entirely). I'm assuming, from the apt method name (another good thing to do), that you want to retrieve the data from the text field. Put this line inside the method (and change the word void to String) and you should be set!
return textField.getText();
Truthfully, this shouldn't even run due to a NullPointerException. You aren't initializing any of the components other than the JFrame. You need to do things like textField = new JTextField(20).
Even if you could run this, the button wouldn't work at all because the button hasn't been told that it does anything. To do this call button.addActionListener() with the name of the listening class as the argument. If the GUI and listening classes happen to be in one class together (like I will show you in a minute), the argument is simply this.
You aren't adding any components to the frame. For every component you wish to put into your frame, you must call add(Component cmpt).
Having said this, I think I'm just going to try to recreate what you're trying to do here into one class. You don't really need two separate classes unless the listening portion is excessively long.
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class TestText extends JFrame implements ActionListener {
JTextField textField = new JTextField(20);
JButton set = new JButton("Set Text");
JButton get = new JButton("Get Text");
public TestText() {
super();
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
add(textField);
set.addActionListener(this); //this tells the program that the button actually triggers an event
add(set);
get.addActionListener(this);
add(get);
pack();
setVisible(true);
}
public void actionPerformed(ActionEvent event) {
if (event.getSource() == set) {
textField.setText(JOptionPane.showInputDialog(null, "Enter a new word for the text field:"));
} else {
System.out.println(textField.getText());
}
}
public static void main(String[] args) {
TestText tt = new TestText();
}
}
After doing some reading I think it is due to my code not accessing the Event Dispatch Thread like #camickr suggested. Here is some documentation that helped me solve my problem.