I want my JTextPane to have some functionality when the user presses Enter and not just change the line. Now I understand how to implement the functionality I want, but I still can't negate the line feed from pressing Enter. I have tried the following but it doesn't seem to work, the new line will be created anyway.
To give a better idea of what I'm trying to achieve here, the textpane is supposed to contain a certain filepath, so I want the user to be able to scroll only horizontaly and not add new lines verticaly. Is the JTextPane component suitable for this use?
locationPane = new JTextPane();
locationPane.addKeyListener(new KeyAdapter() {
#Override
public void keyPressed(KeyEvent arg0) {
if(arg0.getExtendedKeyCode() == KeyEvent.VK_ENTER){
locationPane.setText(locationPane.getText().substring(0, locationPane.getText().length()));
}
}
});
KeyListener is never a suitable soution for text components. Instead you should be using a DocumentFilter to filter out things you don't want to be added to the underlying Document.
See Implementing a Document Filter and DocumentFilter Examples for more details
You could also alter the insert-break key binding, changing the behaviour or taking additional action.
See this example for more details
the textpane is supposed to contain a certain filepath, so I want the user to be able to scroll only horizontaly and not add new lines verticaly. Is the JTextPane component suitable for this use?
I would suggest there are better options.
If you only have a single line of text then just use a JTextField. To handle the Enter key you can add an ActionListener to the text field.
If you do need multiple line then I would suggest you could use a JList.
Related
I have a JTextArea and a button which removes the selected text (from textArea).
RemoveButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
String test = textArea.getSelectedText();
textArea.replaceSelection("");
}
});
The code above works fine, however, when I click the button the text shows like this:
Here I removed the first and third Test. How can I make this dynamically update so it displays the text without gaps?
I could call a method re-populate the JTextArea with the remaining elements but is there a better way to do this?
You can try something like
textArea.setText(textArea.getText().replaceAll("\n\n",""));
However, a TextArea may not be the best component for that kind of use. A Jlist could be more fitted if you want to store input on different lines.
I am using a JEditorPane as a component to show code. The JEditorPane resides in my custom PropertyEditorSupport for my Netbeans Platform app and is show in an OutlineView and the Properties window.
I've already limited the JEditorPane to be one line only, using a DocumentFilter. However I am not able to rebuild the funcionality a JTextField has, to finish input into the component by hitting the ENTER key.
I have already thought about adding a KeyListener event to my JEditorPane but am not sure what to do in case of the event. Is there a method to be called to "finish input of text"?
I am using a JEditorPane as a component to show code.
I've already limited the JEditorPane to be one line only
Those two statements seems to contradict one another. Usually codes consists of multiple lines, not one line.
In any case if you are simply display text then I would use a JTextPane as it supports text attributes. A JEditorPane is used to display HTML.
I have already thought about adding a KeyListener event
Don't use a KeyListener. Swing was designed to be used with Key Bindings. Basically you create an Action (in your case you would extend TextAction) and you bind the Action to a KeyStroke. Check out Key Bindings which contains more information as well as a link to the Swing tutorial on How to Use Key Bindings.
So im creating a server, and that works great, however I am a bit stuck on the GUI. You see, I would like it to look just like Command Prompt, where only the next line is editable, and it does not let you delete any other text. So right now I have:
JTextArea ta = new JTextArea();
JScrollPane sp = new JScrollPane(ta);
Then the frame stuff...
f.setTitle("Server");
f.setBounds(ss.width - 600, 50, 550, 350);
f.setResizable(false);
f.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);//added window listener so closes socket connection first
f.setAlwaysOnTop(true);
Then adding it:
f.add(sc);
jt.setBackground(Color.BLACK);
jt.setForeground(Color.WHITE);
//jt.setEditable(false);
Finally, the method I use to output to the TextArea:
public static void append(String text) {
jt.append(text);
jt.append("\n\n"+System.getProperty("user.name")+" / "+getIp()+" > ");
jt.setCaretPosition(jt.getDocument().getLength());
}
Now I need to assign a String to what the user types into the JTextArea after they press enter:>?
jt.addActionListener(...{
public void ActioEvent(ActionEvent e){
String text = JTextArea.getLines().getLastLine().getText().replace(System.getProperty("user.name")+" / "+getIp()+" > ", "");
}
});
Maybe something like that?
Then I need to have it so that only the part after the ">" is editable?
The way to do this is with a DocumentFilter. This is a fairly obscure and little-used part of Java, and is far from easy to use. However it allows you to insert a DocumentFilter between the UI (where rich text content is edited) and the underlying model (the content). You pass all the 'insert' and 'remove' operations through the filter, which can either accept, refuse or modify them. You can code the filter to only permit modifications to the command line, and not to the prompt.
As I say, this is a pretty hard piece of coding, and the Document/DocumentFilter structure has a lot of complexity that your particular application doesn't need. However it does provide you with the facilities you need.
There is a tutorial in the standard Java doc pages, but not an advanced one, and very few examples that I know of are out there on the web.
ProtectedTextComponent (thanks camickr) provides an example of how to do something similar.
Use a Collection a JTextField.
Let the user type on a JTextField, and once he presses enter, move the control to the next JTextField while making the above JTextField uneditable and also remove the JScrollPane from it.
Hope this helps.
I also agree that the JTextArea/JTextField approach is the common and simpler approach.
However if you want to complicate your life a little then you can check out Protected Text Component which will do most of the logic for you.
The current implemtation of the ProtectedDocument only allows you to add protection to the Document, not remove it so the first thing you will need to do is add a method to "Clear" all the protect pieces of text. This is easy enough, you just clear the entries in the Map used by the class.
Next you will need to replace the default "Enter" Action used by the JTextPane. You do this by playing with the Key Bindings of the text area. See Key Bindings for some basic information. In your custom Action you would first need to invoke the newly created "clear(...)" method. Then you would add you text to the text area. Finally you would protect all the text but the last "x" number of characters.
I'm writing a custom control, based on JTextField. My JTextField uses my own Document class, derived from PlainDocument, so that I can process all the user input in overriden insertString(...) and remove(...) methods.
Here's the problem. After I process user input, sometimes I want to move the caret to another position. What is the better way to do it?
By default Document puts the caret next to last input. So I tried to put a char to my target position and delete it immediately. For some reason it doesn't work in remove() method... and the code doesn't look nice :)
Thanks for and proposals.
It seems unnecessary to extend PlainDocument. Simply add a DocumentListener to the Document of your JTextField and you can process the user input in the 3 methods declared in DocumentListener
Use setCaretPosition to move the caret to wherever you would like
You should actually be using a DocumentFilter if you want to control user input. A DocumentFilter allows you to intercept all the input as it happens. You can then use JTextField.setCaretPosition (comes from JTextComponent) to set the caret position. Just pass your DocumentFilter implementation a reference to the JTextField so it can set the caret position for you.
Here's the Java trail for DocumentFilter. Also, an example on JavaRanch.
I want to highlight the lines which are errors while validating, I am currently using jtextarea, looked into jtextpane and styles, i need some suggestions in implementing like the below way. Should i have to take jtextarea or jtextpane or any other best and easy option? thanks
private void validate(String text){
lines = text.split("\n");
for(String line : lines){
if(line.substring(0, 1).equals("")){
//want to highlight the entire line in red color
} else {
//remove the highlight
}
}
}
Use
textarea.getHighligter().addHighlight()
See the doc DefaultHighlighter and Demos and Usage of DefaultHighlighter
JTextArea will certainly not work as it only supports plain text. You will need a JTextPane. A handy overview (as I always forget which one does what) can be found in the Swing tutorial
For your validation, I would add a DocumentListener which validates the input and changes the color depending on the state.