<AWT Dev> [10] Review request for 8166772: Touch keyboard is not shown for text components on a screen touch

Anton Litvinov anton.litvinov at oracle.com
Thu Aug 17 12:20:06 UTC 2017


Could you please review the following fix for the bug.

Bug: https://bugs.openjdk.java.net/browse/JDK-8166772
Webrev: http://cr.openjdk.java.net/~alitvinov/8166772/jdk10/webrev.00

The bug is the fact that, when a user touches any Swing or AWT text 
component, for example "JTextField", "JTextArea", "TextField", 
"TextArea", by means of a touch screen on a host with MS Windows 
10/8.1/8 OS, the system touch keyboard is not shown automatically. 
Please find a detailed description of the bug, screenshots depicting the 
touch keyboard and a compilable test case with Swing/AWT text components 
in JBS bug record. Also a summary of the done research of the issue with 
a description of identified approaches for its resolution are reported 
in my last comment in the bug record.

On a very abstract level the fix functioning can be presented by the 
next 3 stages:

Stage 1.
The fix adds support of "WM_TOUCH" system window messages to AWT native 
peer windows through C++ class "AwtComponent". It "processes" "WM_TOUCH" 
message and marks "java.awt.event.MouseEvent", which is created as a 
result of handling of the further coming "WM_LBUTTONDOWN", 
"WM_LBUTTONUP" messages sent by the system in substitution for this 
"WM_TOUCH" message, by the new private field flag 

Stage 2.
Then on Java level the fix handles "MouseEvent", "FocusEvent" received 
only by the instances of "java.awt.TextComponent", 
"javax.swing.text.TextComponent" in "WToolkit.showOrHideTouchKeyboard()" 
called from "Component.dispatchEventImpl()" and shows or hides the touch 
keyboard on "MouseEvent.MOUSE_RELEASED" and "FocusEvent.FOCUS_LOST" 
events by calling corresponding native methods of "WToolkit" class.

Stage 3.
Showing of the touch keyboard is implemented in C++ class "AwtToolkit" 
and is done by launching the system application "TabTip.exe" which 
implements the system touch keyboard. This approach is described in the 
bug record.

1. By default all native and Java parts of the fix do not function at 
all - the fix is disabled. To enable the fix the application should be 
run with "-Dawt.touchKeyboardAutoShowIsEnabled=true" option. Handling of 
this new property is implemented in "sun.awt.SunToolkit" class.

2. Native parts of the fix functions only on MS Window 8 or later.

3. The fix implements automatic showing of the touch keyboard for the 
following 2 use cases:
     a.  The user touches the text components using the touch screen.
     b.  The user does mouse clicks on the text components, while no any 
keyboard is attached to the host.

1. Core of the fix:
     Native code:  awt_Toolkit.[h/cpp], awt_Component.[h/cpp], 
awt_MouseEvent.[h/cpp], awt.h
     Java:  SunToolkit.java, WToolkit.java, Component.java, 
MouseEvent.java, AWTAccessor.java

2. Changes in all remaining Java files are connected with retaining of 
the flag value "MouseEvent.causedByTouchEvent" during creation of the 
new instances of "MouseEvent" class based on the original "MouseEvent" 

Work of the fix was verified both in the environment with the real touch 
screen device and in the environment with the emulated touch screen.

Thank you,

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