[Development] QPlatformInputContext needs more informations

[BogDan]

> From: Pekka Vuorela <pekka.ta.vuorela at nokia.com>

> To: BogDan <bog_dan_ro at yahoo.com>
> Cc: Samuel Rødal <samuel.rodal at nokia.com>; "development at qt-project.org" <development at qt-project.org>
> Sent: Tuesday, April 17, 2012 5:12 PM
> Subject: Re: [Development] QPlatformInputContext needs more informations
> 
> On Mon, 2012-04-16 at 09:23 -0700, ext BogDan wrote:
>>  > From: Pekka Vuorela <pekka.ta.vuorela at nokia.com>
>>  > To: BogDan <bog_dan_ro at yahoo.com>
>>  > Cc: Samuel Rødal <samuel.rodal at nokia.com>; 
> "development at qt-project.org" <development at qt-project.org>
>>  > Sent: Monday, April 16, 2012 12:57 PM
>>  > Subject: Re: [Development] QPlatformInputContext needs more 
> informations
>>  > 
>>  > On Mon, 2012-04-16 at 01:17 -0700, ext BogDan wrote:
>>  >>  > From: Samuel Rødal <samuel.rodal at nokia.com>
>>  > 
>>  >>  >>  In order to be sure the user sees the entire control 
> and its 
>>  > content I need 
>>  >>  > to know
>>  >>  >>  the control position and its size, otherwise the 
> virtual keyboard 
>>  > may cover 
>>  >>  > the 
>>  >>  >>  control and its content.
>>  >>  > 
>>  >>  > Isn't that what QPlatformInputContext::keyboardRect() is 
> for?
>>  >>  > 
>>  >> 
>>  >>  On Android platform the keyboard rect is unknown, because is an 
> external 
>>  > service.
>>  >>  The only way to be sure the user will see the entire control and 
> its 
>>  > content,
>>  >>  is to create a dummy transparent Android native widget in the 
> same position 
>>  > and 
>>  >>  with the same size as the qt control, I pass that widget to the 
> keyboard 
>>  > service, 
>>  >>  then the Android window manager will do the magic for me, it will 
> pan the 
>>  > screen or 
>>  >>  it will resize it if necessary.
>>  >>  Please check the video I posted on youtube [1].
>>  > 
>>  > On Meego, at least, the panning and resizing has been made 
> application's
>>  > responsibility. That's why the keyboard rectangle is available and 
> not
>>  > the other way around
>>  > 
>>  > I don't know the Android interfaces, but would it be then possible 
> to
>>  > infer keyboard size by creating a transparent fullscreen native widget
>>  > and seeing how much the window manager resizes it?
>>  >
>> 
>>  I'm afraid is not possible (at least not in all cases). If you check 
> the video
>>  I posted on youtube you'll see that there are 3 different cases on how 
> the
>>  virtual keyboard interacts with the screen and in only one case the screen
>>  is resized.
>>  Let me give you more explanation about that video.
>>  - the first case is when the widget is small so the screen doesn't need 
> to
>>  be resize, but the control will be covered by the keyboard, so the whole 
>>  screen must be moved up.
>>  - the second case is when the widget is too big and the screen must be
>>  resized in order to make room for virtual keyboard, it can not be moved up
>>  because the user will not see the entire control or its content. This is 
> the
>>  only case when I know how determine the keyboard size.
>>  - the third and the last case is when widget is small enough and it will
>>  not be covered by the keyboard, in this case the keyboard will just appear
>>  on top of your app, no panning and no resize is needed.
>> 
>>  Even if with magic trick I'll get the keyboard size, on android is not 
> helping
>>  too much, because I still need to know the control position and size,
>>  otherwise I don't see how can I decide which from the 3 cases to 
> choose. 
>> 
>>  So pretty please consider to add this information, otherwise we'll have 
> to
>>  do some super dirty workarounds to get it working on Android.
> 
> What you describe above is how Android is making sure editors stay
> visible. There is nothing per se requiring panning and resizing
> happening exactly as above. For example, just always resizing the window
> to remaining visible area would be a start. Meegotouch on N9 on the
> other hand never resizes the window for this, it just adds some
> temporary extra space to scrollable widget and scrolls what is
> necessary. Application/toolkit being in charge how it wants to ensure
> editor visibility.
> 
>
> What I meant with the fullscreen window to infer keyboard size was to
> get QInputMethod::keyboardRectangle() return the correct size. Editor
> knows its size so it could then trigger similar behavior what you
> described above. 
> 

  It will be strange for Android users, I want Qt apps to look&*feel* the same
as any native Android application.

>
> I'd be careful adding this to inputmethod queries. E.g. usage would also
> need similar transformations as were done for cursorRectangle in
> QInputMethod.
>

I created a new patch which adds itemBoundingRect property to QInputMethod.

Please let me know if this approach is better :)

Cheers,
BogDan.
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