<Swing Dev> DnD fails with JTextArea and JTextField
Pavel Porvatov
pavel.porvatov at oracle.com
Tue Sep 20 11:14:15 UTC 2011
Hi Sean,
The have several comments :
1. Could you please read http://openjdk.java.net/jtreg/
is it possible run your test via jtreg?
2. There is no copyright in the begin of test
3. There are no jtreg tags
4. All Swing code must be initialized on the EDT thread
5. Keep test minimal as possible, please. It helps other people to
understand your code.... E.g. there is no need to create JButton with
listener.
6. Note that the "frame.setVisible(true)" doesn't guarantee that after
that line Frame is visible, you should use toolkit.realSync() here
7. No TODO, please
8. Are you sure your test should pass if exceptions occurs (see your
catch blocks)
Please take a look at other tests and use them as a good examples....
Regards, Pavel
> Hi Pavel,
>
> I wrote a test case for the behavior of DefaultCaret. Please take a
> look, it is
> attached.
>
>
>
> 2011/9/15 Pavel Porvatov <pavel.porvatov at oracle.com
> <mailto:pavel.porvatov at oracle.com>>
>
> Hi Sean,
>> Hi Pavel,
>>
>> I'm comfortable with moving the checking into
>> DefaultCaret#updateSystemSelection method.
>> About regression test, I'm not sure how to write, because it
>> contains user operation. Can you
>> give me a similar test so I can write one for this bug?
> Yes, you can find a lot examples in the test/javax/swing directory
> by word Robot, e.g.
> test\javax\swing\JSlider\6848475\bug6848475.java. One hint: use
> reflection ONLY if there are no another ways to write a test...
>
> Regards, Pavel
>
>>
>> 2011/9/13 Pavel Porvatov <pavel.porvatov at oracle.com
>> <mailto:pavel.porvatov at oracle.com>>
>>
>> Hi Sean,
>>> Hi Pavel ,
>>>
>>> I'm sorry I didn't make update for this bug for a long
>>> time, and here is some
>>> recent investigation. The scenario is as follows:
>>>
>>> Suppose we are dragging "abcde" over TextField tf, which
>>> have "hello dragging" as
>>> its content. When we are dragging from start to end, there
>>> is a cursor moving from
>>> "h" to "g", which means the place to insert "abcde" if we
>>> drop it.
>>> When we dragging "abcde" exit tf, there will be a dragExit
>>> event, the tf needs to
>>> restore its original status after we drag out. Eg. if its
>>> cursor is between "h" and
>>> "e" in "hello", which appears like "h|ello", when we are
>>> dragging over it, it may like
>>> "hello dr|agging", and when drag exit, it needs to be
>>> "h|ello" again.
>>> So in dragExit handler, it calls
>>> javax.swing.TransferHandler.cleanup(false), which
>>> means only to restore the original state. cleanup calls
>>> javax.swing.text.JTextComponent.setDropLocation to set the
>>> cursor to original
>>> position. And setDropLocation calls DefaultCaret.setDot
>>> and DefaultCaret.moveDot
>>> to set the state.
>>> The problem is moveDot doesn't know this is just to restore
>>> the original state,
>>> it treats the invocation as an action to select something.
>>> And it calls updateSystemSelection
>>> which will call java.awt.datatransfer.Clipboard.setContent.
>>> And the selected content
>>> is changed from "abcde" to the original selected part of
>>> "hello dragging", then
>>> the drop operation finds it is not the string dragged and
>>> nothing is dropped.
>>>
>>> So I made a simple patch(attached) . It just check if the
>>> textField owns focus
>>> before updateSystemSelection, if it is not focused, it does
>>> not treat the moveDot as
>>> a selection action and does not call Clipboard.setContent.
>>> This works on Linux,
>>> however, DefaultCaret is shared by Linux and Windows while
>>> windows doesn't have
>>> this problem. So I don't think this is a correct patch, but
>>> it brings my question.
>>>
>>> I think it is strange for DefaultCaret to use setDot and
>>> moveDot to restore
>>> original state, especially moveDot will cause
>>> an updateSystemSelection operation,
>>> which makes moveDot much like an action from user instead of
>>> just restoring state.
>>>
>>> I'm not sure why it works well on windows, but I don't think
>>> it is right to call
>>> updateSystemSelection or it is not right to use setDot and
>>> moveDot to restore
>>> the original state. Is there any reason for that ?
>> Thanks for the patch! I believe you are right and we
>> shouldn't update system selection clipboard when the
>> component doesn't have focus. I'd like to modify your fix and
>> move checking into the DefaultCaret#updateSystemSelection method:
>> if (this.dot != this.mark && component != null &&
>> component.hasFocus()) {
>>
>> We also must write regression tests for fixes if possible, so
>> an automatic test is needed as well. Could you please write a
>> test for the fix?
>>
>>
>> > I'm not sure why it works well on windows,
>> That's because Windows doesn't have system selection
>> clipboard...
>>
>>
>> > Is there any reason for that ?
>> No, that's a just bug...
>>
>> Regards, Pavel
>>
>>>
>>> 2011/6/6 Pavel Porvatov <pavel.porvatov at oracle.com
>>> <mailto:pavel.porvatov at oracle.com>>
>>>
>>> Hi Sean,
>>>> Hi,
>>>>
>>>> I reported, but the system doesn't reply me a bug
>>>> number. It says "will give me email",
>>>> but I haven't got one yet. Is this the right process,
>>>> or I might make a problem when
>>>> reporting?
>>> I don't know why the system didn't report bug ID, but
>>> your bug was filed successfully. You can find it here:
>>> http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7049024
>>>
>>> Regards, Pavel
>>>
>>>>
>>>> 2011/5/27 Pavel Porvatov <pavel.porvatov at oracle.com
>>>> <mailto:pavel.porvatov at oracle.com>>
>>>>
>>>> Hi Sean,
>>>>> Hi all,
>>>>>
>>>>> I have a testcase related to DnD failure with
>>>>> JTextArea and JTextField on linux. The
>>>>> testcase is as follows:
>>>>>
>>>>> /*
>>>>> * DnDTest.java
>>>>> */
>>>>> import java.awt.Color;
>>>>> import java.awt.Component;
>>>>> import java.awt.Dimension;
>>>>> import java.awt.FlowLayout;
>>>>> import java.awt.Frame;
>>>>> import java.awt.event.WindowAdapter;
>>>>> import java.awt.event.WindowEvent;
>>>>>
>>>>> import javax.swing.JTextArea;
>>>>> import javax.swing.JTextField;
>>>>>
>>>>>
>>>>> public class DnDTest extends Frame {
>>>>> Component c;
>>>>> public DnDTest() {
>>>>> super("Single Frame --- AWT Frame");
>>>>> super.setBackground(Color.gray);
>>>>> // set layout here.
>>>>> setLayout(new FlowLayout());
>>>>> c = new JTextArea("JTextArea component");
>>>>> c.setPreferredSize(new Dimension(400, 100));
>>>>> add(c);
>>>>> c = new JTextField("JTextField component(No IM)");
>>>>> c.setPreferredSize(new Dimension(400, 20));
>>>>> add(c);
>>>>> addWindowListener(new WindowAdapter() {
>>>>> public void windowClosing(WindowEvent event) {
>>>>> System.exit(0);
>>>>> }
>>>>> });
>>>>> setSize(850, 360);
>>>>> setVisible(true);
>>>>> }
>>>>> public static void main(String[] args) {
>>>>> new DnDTest();
>>>>> }
>>>>> }
>>>>>
>>>>>
>>>>> Reproduce steps:
>>>>> 1. Run the testcase with b143
>>>>> 2. Open a new file with gedit and input some words
>>>>> like "abcde"
>>>>> 3. Drag "abcde" into JTextField and drop it there.
>>>>> 4. Once more, drag "abcde" into JTextField and
>>>>> then move out of the Frame (keep draging) and drag
>>>>> into JTextField again and drop it.
>>>>>
>>>>> Expectation:
>>>>> The second DnD inputs another "abcde" into JTextField.
>>>>>
>>>>> Result:
>>>>> The second DnD inputs nothing into JTextField.
>>>> Yes, looks like a bug. The test case works on
>>>> Windows as expected.
>>>>
>>>>>
>>>>> Investigation:
>>>>> The JTextArea as well has this problem, and in
>>>>> step 4, if we drag "abcde" over JTextField and
>>>>> then drop into JTextArea, nothing
>>>>> is input into JTextArea either. However, if
>>>>> "abcde" is drag into JTextField or JTextArea
>>>>> directly or when JTextArea/Field are
>>>>> empty as in step 2, it works.
>>>>>
>>>>>
>>>>> Are there any comments? And can anyone file a bug
>>>>> for it please ?
>>>> Anybody can file a bug,
>>>> http://bugreport.sun.com/bugreport/
>>>>
>>>> Regards, Pavel
>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Best Regards,
>>>> Sean Chou
>>>>
>>>
>>>
>>>
>>>
>>> --
>>> Best Regards,
>>> Sean Chou
>>>
>>
>>
>>
>>
>> --
>> Best Regards,
>> Sean Chou
>>
>
>
>
>
> --
> Best Regards,
> Sean Chou
>
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