RobCSP
asked on
Control a JScrollpane with keyboards
Hi experts,
I have a JTextarea,inside a JscrollPane, the content exceeds the size of the area, for what I want that the user could see the whole content without need to use the mouse, that is to say, that could move the scroll by means of the keyboard.
I have a JTextarea,inside a JscrollPane, the content exceeds the size of the area, for what I want that the user could see the whole content without need to use the mouse, that is to say, that could move the scroll by means of the keyboard.
Shall we assume that the JTextArea is ineditable? Because otherwise, you can use the Pg Down or the down-arrow buttons to go to the bottom of the text-area if the cursor is inside it.
Keystroke-mappings are available for JScrollPane:
http://java.sun.com/j2se/1.4.2/docs/api/javax/swing/doc-files/Key-Metal.html#JScrollPane (Java L&F)
http://java.sun.com/j2se/1.4.2/docs/api/javax/swing/doc-files/Key-Windows.html#JScrollPane (Windows L&F)
http://java.sun.com/j2se/1.4.2/docs/api/javax/swing/doc-files/Key-Motif.html#JScrollPane (Motif L&F)
http://java.sun.com/j2se/1.4.2/docs/api/javax/swing/doc-files/Key-Metal.html#JScrollPane (Java L&F)
http://java.sun.com/j2se/1.4.2/docs/api/javax/swing/doc-files/Key-Windows.html#JScrollPane (Windows L&F)
http://java.sun.com/j2se/1.4.2/docs/api/javax/swing/doc-files/Key-Motif.html#JScrollPane (Motif L&F)
Hi RobCSP,
>> I have a JTextarea,inside a JscrollPane
Why do you need to put the JTextArea inside a JScrollPane ? JTextArea already have scrollbars.
>> I have a JTextarea,inside a JscrollPane
Why do you need to put the JTextArea inside a JScrollPane ? JTextArea already have scrollbars.
The java.awt.TextArea internally handles scrolling. JTextArea is different in that it doesn't manage scrolling, but implements the swing Scrollable interface. This allows it to be placed inside a JScrollPane if scrolling behavior is desired, and used directly if scrolling is not desired.
You just need to set teh focus to the JScrollPane for doing that.
JScrollPane jsp = new JScrollPane ( t ) ; // t is an ineditable JTextArea
getContentPane ().add ( jsp ) ;
show () ;
jsp.requestFocus () ; // sets the focus to the JScrollPane
- then, you can try scrolling up and down with the Up/ Down arrow keys
JScrollPane jsp = new JScrollPane ( t ) ; // t is an ineditable JTextArea
getContentPane ().add ( jsp ) ;
show () ;
jsp.requestFocus () ; // sets the focus to the JScrollPane
- then, you can try scrolling up and down with the Up/ Down arrow keys
ASKER
Shall we assume that the JTextArea is ineditable? Yes
JTextArea already have scrollbars.
Are you sure???
Keystroke-mappings are available for JScrollPane: I know that,but in this way you move the cursor, ok when you move the cursor,the scroll moves, but it produces strange jumps, that´s the reason why my boss(not me) want that the user control the scroll with the key arrows.
Can i add a keyListener to the JScrollPane and control the area displayed by it????
i come back in 2 hours thnx for the help
JTextArea already have scrollbars.
Are you sure???
Keystroke-mappings are available for JScrollPane: I know that,but in this way you move the cursor, ok when you move the cursor,the scroll moves, but it produces strange jumps, that´s the reason why my boss(not me) want that the user control the scroll with the key arrows.
Can i add a keyListener to the JScrollPane and control the area displayed by it????
i come back in 2 hours thnx for the help
You don't need to add any key-listener. Try out the requestFocus () example that I posted. Should work (works for me). JTextArea does not manage scrolling on its own, unlike TextArea. That's why it implements Scrollable, so that you can add it to a JScrollPane if scrolling is desired.
ASKER
I try it, ok the scroll works but this is not what i want because the jumps still happening, i want to control directly the scroll.
Test with a text that exceed the text area horizontal and vertically and you will see my problem.
thnx
Test with a text that exceed the text area horizontal and vertically and you will see my problem.
thnx
Try setting the unit-increment with jsp.getVerticalScrollBar ().setUnitIncrement () before you display the Container.
Is my understanding of 'jump' correct? Do you mean that when you press the down-key, it scrolls a long way down the JTextArea? Is that correct?
By the way, there is a significant difference in the amount it scrolls down if you use the Down button and the Page-Down button.
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ASKER
Hi, i try with setUnitIncrement but the problem persist, my text area display text obtained from a text file
/************text example*********/
\n\n\n-------------------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- --------\n OPERACION CONT TIPO ANUL MONEDA CAMBIO CANTIDAD EUROS NOMBRE DNI RESIDENCIA FECHA USUARIO \n------------------------ ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ----\n\n67 VENTA DE BILLETES SI wqrwe wqeqw qweqe qweqeqw eqeq 2004_04_06 13:30:13 Rob \n DOLAR USA 768 0,8046408296 954.46 \n\n\n\n\n---------------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- --\nOPERAC ION CONT TIPO ANUL MONEDA CAMBIO CANTIDAD EUROS NOMBRE DNI RESIDENCIA FECHA USUARIO \n------------------------ ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ----\n\n68 VENTA DE BILLETES SI wqrwe wqeqw qweqe qweqeqw eqeq 2004_04_06 13:30:13 Rob \n DOLAR USA 768 0,8046408296 954.46 \n\n\n\n\n\n-------------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ----\nOPER ACION CONT TIPO ANUL MONEDA CAMBIO CANTIDAD EUROS NOMBRE DNI RESIDENCIA FECHA USUARIO \n------------------------ ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ----\n\n69 VENTA DE BILLETES SI wqrwe wqeqw qweqe qweqeqw eqeq 2004_04_06 13:30:13 Rob \n DOLAR USA 768 0,8046408296 954.46 \n\n\n\n\n\n-------------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ----\nOPER ACION CONT TIPO ANUL MONEDA CAMBIO CANTIDAD EUROS NOMBRE DNI RESIDENCIA FECHA USUARIO \n------------------------ ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ----\n\n70 VENTA DE BILLETES SI wqrwe wqeqw qweqe qweqeqw eqeq 2004_04_06 13:30:13 Rob \n DOLAR USA 768 0,8046408296 954.46 \n
/************ end of text example************/
Because of the blank lines, if i move the cursor the "jumps" begin, that the reason why i want to know if i can control directly the displayed area of a JscrollPane.
i see the links, but i don´t find it useful.
/************text example*********/
\n\n\n--------------------
/************ end of text example************/
Because of the blank lines, if i move the cursor the "jumps" begin, that the reason why i want to know if i can control directly the displayed area of a JscrollPane.
i see the links, but i don´t find it useful.
Well, the setUnitIncrement () method is perhaps meant for that purpose only. There is also one setBlockIncrement () but I don't know what it does - never tried it. Try printing the value of unit-increment by getUnitIncrement (). Does it give something close to 10? Try setting it to 1.