Chinese input on ios doesn't work

I tried the ios qt.
I found one issue with the input method.
While the English input method does work, the Chinese input method doesn't.

I'm attaching two screenshots,
the first one is the ios note app. As you can see, when typing Chinese, there is an extra bar above the virtual keyboard that shows Chinese characters.

But within the Qt program (screenshot 2), the extra bar doesn't show and I can't type anything.

I will look deeper this weekend see what's going on.