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How to detect when a user presses a key outside of the app [duplicate]

This question already has answers here:
Java - checking if parseInt throws exception
(8 answers)
Closed 1 year ago.
So I tried to look a bit in forums and StackOverflow but nothing worked for me I need when enter is pressed to stop my code this is my code `
JFrame f;
JTextField I;
// JButton
JToggleButton b;
// label to display text
JLabel l;
f = new JFrame("AutoClicker");
i = new JTextField("100");
// create a label to display text
l = new JLabel("clicks/seconds");
// create a new buttons
b = new JToggleButton("Start");
// create a panel to add buttons
JPanel p = new JPanel();
// add buttons and textfield to panel
p.add(b);
p.add(i);
p.add(l);
// setbackground of panel
p.setBackground(Color.red);
// add panel to frame
f.add(p);
// set the size of frame
f.setSize(280, 80);
f.setVisible(true);
b.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
int jml = Integer.parseInt(i.getText());
if(jml < 50)
{
jml = 50;
}
AutoClicker(jml);
}
});
}
static void AutoClicker(int jml)
{
while(true)
{
try{
Robot r = new Robot();
int button = InputEvent.BUTTON1_DOWN_MASK;
r.mousePress(button);
Thread.sleep(jml);
r.mouseRelease(button);
Thread.sleep(jml);
}
catch(Exception e){
e.printStackTrace();
System.out.println("not good");
}
}
}
}`
I tried to add a KeyListener but it did not work.
I don't understand why it doesn't work so if you can just help me know why it doesn't work it would be much apreciated.

KeyListener isn't going to solve the problem of the fact that you are simply not handling the potential of Integer.parseInt to throw an exception - I mean, how can it convert "" or "This is not a number" to an int. In those cases it throws an exception
The JavaDocs clearly state
Throws:NumberFormatException - if the string does not contain a
parsable integer.
Go back and have a look at the original error you were getting from your previous question on this exact topic
java.lang.NumberFormatException: For input string: "Enter"
It's telling you exactly what the problem is - the text "Enter" can not be converted to an int value.
YOU have to handle this possibility. No offence, but this is honestly basic Java 101. See Catching and Handling Exceptions
Another option which "might" help is to use a formatted text field
You also don't seem to have a firm grip on the concept of what a "event driven environment" is or what the potential risk of what doing something like while (true) will do if executed within the context of the Event Dispatching Thread. This makes me think you've got yourself in over all head.
You're going to want to learn about Concurrency in Swing as AutoClicker should never be called within the context of the Event Dispatching Thread, which is going to lead you another area of complexity, concurrency and all the joys that brings.
Updated
Wow, you changed the title. Maybe a better description of the problem you're trying to solve would have a gotten a better answer. In short, you can't, not natively in Java anyway. The only way you can detect keyboard input out side of the app is using native integration, JNA/JNI. Plenty of examples about, for example

How to make a textarea filled with text (label) every time the button pressed?

I'm trying to make a text area record that every time the button is press, it means that it has been recorded and should be showing record1, record2, record3, etc. on it.
My goal is that, every button is pressed it will add text to the text area with different text label so that no redundancy.
I tried it with my own with this:
private void btnReqstRefreshActionPerformed(java.awt.event.ActionEvent evt) {
JLabel labelthis = new JLabel("record1");
label.setSize(label.getPreferredSize());
TextArea1.add(label);
TextArea1.revalidate();
TextArea1.repaint();
}
I know it is wrong, but is it possible?

text area is like a mini text editor - you add text to it not other components. Instead of adding labels - just add the text. Something like:
TextArea1.setText(TextArea1.getText() + "record1")
This should append record1 to the existing text in the text area.

According to my experience this is possible.
`private void btnReqstRefreshActionPerformed(java.awt.event.ActionEvent evt) {
i++;//i class level variable(static) to avoid redundancy
//labelThis initialized earlier should be accessible here
String oldText = labelThis.getText().toString();
oldText += "record "+i;
labelThis.setSize(labelThis.getPreferredSize());
TextArea1.add(labelThis);
TextArea1.revalidate();
TextArea1.repaint();
}`

Dynamic text box in Java

how do I make a text box which the user can insert text into, then that text can be saved to some variable?

JTextField is probably the class you are looking for.
JTextField textField = new JTextField();
yourPanel.add(textField);
This will add the textField into your JPanel. Then at any point in your code where you have a handle to your textField, call getText(); of your JTextField.
String s = textField.getText();
See this tutorial for a better reference:
http://download.oracle.com/javase/tutorial/uiswing/index.html

A JTextField or JTextArea will do what you are asking for, but you'll need either a button or a listener to actually know when to save this to a String.
javax.swing is Event based, which means that you cannot extract the text like this:
JTextField myField = new JTextField();
//wait for user input
String s = myField.getText(); //not guaranteed to work!
Instead, you may want to make a "Submit" button that will send the text to your program when it is clicked:
http://download.oracle.com/javase/tutorial/uiswing/components/button.html

Example text in JTextField

I am looking for a way to put example text into a swing JTextField and have it grayed out. The example text should then disappear as soon as any thing is entered into that text field. Some what similar to what stackoverflow does when a user is posting a question with the title field.
I would like it if it was already a extended implementation of JTextField so that I can just drop it in as a simple replacement. Anything from swingx would work. I guess if there is not an easy way to do this my option will probably be to override the paint method of JTextField do something that way maybe.
Thanks

The Text Prompt class provides the required functionality without using a custom JTextField.
It allows you to specify a prompt that is displayed when the text field is empty. As soon as you type text the prompt is removed.
The prompt is actually a JLabel so you can customize the font, style, colour, transparency etc..:
JTextField tf7 = new JTextField(10);
TextPrompt tp7 = new TextPrompt("First Name", tf7);
tp7.setForeground( Color.RED );
Some examples of customizing the look of the prompt:

If you can use external librairies, the Swing components from Jide software have what you are looking for; it's called LabeledTextField (javadoc) and it's part of the JIDE Common Layer (Open Source Project) - which is free. It's doing what mklhmnn suggested.

How about initialize the text field with default text and give it a focus listener such that when focus is gained, if the text .equals the default text, call selectAll() on the JTextField.

Rather than overriding, put a value in the field and add a KeyListener that would remove the value when a key stroke is registered. Maybe also have it change the foreground.
You could wrap this up into your own custom JTextField class that would take the default text in a constructor.

private JLabel l;
JPromptTextField(String prompt) {
l = new JLabel(prompt, SwingConstants.CENTER);
l.setForeground(Color.GRAY);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (this.getText().length() == 0) {
// Reshape the label if needed, then paint
final Rectangle mine = this.getBounds();
final Rectangle its = l.getBounds();
boolean resized = (mine.width != its.width) || (mine.height != its.height);
boolean moved = (mine.x != its.x) || (mine.y != its.y);
if (resized || moved)
l.setBounds(mine);
l.paint(g);
}
}

You can't do that with a plain text field, but you can put a disabled JLabel on top of the JTextField and hide it if the text field gets the focus.

Do it like this:
Define the string with the initial text you like and set up your TextField:
String initialText = "Enter your initial text here";
jTextField1.setText(initialText);
Add a Focus Listener to your TextField, which selects the entire contents of the TextField if it still has the initial value. Anything you may type in will replace the entire contents, since it is selected.
jTextField1.addFocusListener(new java.awt.event.FocusAdapter() {
public void focusGained(java.awt.event.FocusEvent evt) {
if (jTextField1.getText().equals(initialText)) {
jTextField1.selectAll();
}
}
});

How do I use requestFocus in a Java JFrame GUI?

I am given an assignment but I am totally new to Java (I have been programming in C++ and Python for two years).
So we are doing GUI and basically we extended JFrame and added a couple fields.
Say we have a field named "Text 1" and "Text 2". When user presses enter with the cursor in Text 1, move the focus to Text 2. I tried to add
private JTextField textfield1() {
textfield1 = new JTextField();
textfield1.setPreferredSize(new Dimension(200, 20));
textfield1.addActionListener(
new ActionListener() {
public void actionPerformed(ActionEvent e) {
textfield1text = textfield1.getText().trim();
textfield1.setText(textfield1text);
System.out.println(textfield1text);
textfield1.requestFocus();
}
});
return textfield1;
}
But that doesn't work at all.
I noticed that requestFocus is not recommended, and instead one should use requestFocusWindows. But I tried that too. Upon some readings it seems like I have to do keyboard action and listener? But my teacher said it only requires 1 line...

Well, you have textfield1.requestFocus(), but your description would imply you need textfield2.requestFocus(). (that's 2).

Another option might be to use:
textField1.transferFocus();
This way you don't need to know the name of the next component on the form.