Popping up the Touch Keyboard in Windows

[andpad]

Hello,

I've embedded CEF into a Win32 C++ app which needs to function on touchscreen machines as well as non-touchscreen. I'm currently having issue where clicking on a text box (in a webpage) does not bring up the Windows touch keyboard. I've done some google searching to see how I can make this work, but so far I've been unsuccessful.

I found this related issue post for CefPython https://github.com/cztomczak/cefpython/issues/57 and tried a couple of things:

I've embedded the following switches in my OnBeforeCommandLineProcessing handler and OnBeforeChildProcessLaunch:

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 command_line->AppendSwitchWithValue(CefString("touch-events"), CefString("enabled"));
command_line->AppendSwitchWithValue(CefString("disable-usb-keyboard-detect"), CefString("1"));

I registered the browser as a touch window in my OnAfterCreated handler:

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RegisterTouchWindow(browser->GetHost()->GetWindowHandle(), NULL);

The second comment in the CefPython issue says

When clicking an edit field there is no virtual keyboard appearing, but this could be implemented on your own by injecting javascript on web pages through LoadHandler.OnLoadStart() or OnLoadEnd(), the
same can be done for other touch related behavior, when --touch-events=enabled flag is passed then javascript touch events will be enabled (touchstart, touchend, touchmove), allowing you to override the default behavior or implement the missing one.

However, I'm not a web developer, so I'm not sure how it would be possible to accomplish this by injecting javascript. I'm assuming they must be referring to some method of accessing some Windows API to bring up the keyboard, but I haven't found anything related to that in my searching.

Any help is appreciated.

Thank you.

[Czarek]

The cefpython issue you reference is old. What OS? What CEF version? Are you using windowed rendering or off-screen rendering? Have you tested with cefclient sample application? Does touch keyboard appear in Google Chrome on that same machine?

Update:
Do you have a physical keyboard plugged in when testing? Try "--disable-usb-keyboard-detect" flag.

[andpad]

Update:
Do you have a physical keyboard plugged in when testing? Try "--disable-usb-keyboard-detect" flag.

I was previously testing with a Wacom touch screen tablet (DTH-1152) connected to my laptop, and I couldn't get that working ( even with the "--disable-usb-keyboard-detect" enabled).

I just did a test on an HP All-In-One-PC (24-g237c) with the "--disable-usb-keyboard-detect" flag and with the keyboard disconnected and It worked.
The touch keyboard also comes up when the keyboard is connected and a touch is used to gain focus on a textbox.

I'll be testing with a Microsoft Surface Book tomorrow.

To get clarification, do touch events only get enabled if no keyboard is detected?

BTW, using Windows 10 and cef_binary_3.3163.1671.g700dc25_windows32.

[andpad]

I tested by doing a finger touch on a textbox with a Microsoft Surface Book. I saw that the touch keyboard only comes up when the laptop is in tablet mode. This is also the case with cefclient. These tests were done with the "--touch-events=enabled" and "--disable-usb-keyboard-detect" flags.
Additionally, using the Surface Book's pen does not work at all, only a finger touch seems to bring up the touch keyboard.

This actually seems to function as expected with the latest Chrome (Chromium version 65.0.3325.181) in desktop mode with neither of these flags applied. So hopefully using a CEF build with Chromium ver 65.0.3325.181 or later should work. I'll be testing this tomorrow.