[3.2] [iOS] Keyboard input changes

[naithar]

Added a cursor_start and cursor_end parameters for TextEdit control.
Changed a way iOS's keyboard is handled by moving handing into separate class. Now it can display suggestions view for languages that require it. This change also allows to receive text changes made by dictation or any other text input method.

Fixes #43256 for 3.2 branch

[naithar]

Since this PR changes how TextEdit's virtual keyboard work, I think it should also be tested on Android by someone if it's possible.

[pouleyKetchoupp]

I've finally tested on Android and spotted an issue. It doesn't seem to be platform specific.

Repro steps are:
1.Launch android-ui.zip
2.Select the TextEdit control
3.Type abcd
4.Select the LineEdit control
5.Select the TextEdit control again (after abcd)
6.Press backspace on the virtual keyboard
7.Observe backspace is not working

There's an error in the log when the virtual keyboard is triggered:

ERROR: TextEdit::_base_get_text: Index p_to_column = 5 is out of bounds (text[p_to_line].length() + 1 = 5).
   At: scene\gui\text_edit.cpp:4018

On this line in the new code:

String text = _base_get_text(0, 0, selection.selecting_line, selection.selecting_column);

I can confirm selection.selecting_column is 5 and not 4 in this scenario by debugging step by step on Windows (and forcing the virtual keyboard path).

Can you reproduce this issue on iOS?

I haven't tested on master, so I'm not sure if the 4.0 version of this PR has the same problem.
Edit: I can reproduce it on master, I've open an issue: #44416

[naithar]

@pouleyKetchoupp thanks!
I've managed to reproduce this issue on your MRP, but my test project wasn't reproducing this bug.
Latest commit should fix this issue, but I'll run more tests just to be sure.

[naithar]

Found some strange bug. My old test project gives me incorrect text input and duplicates the text.
I'll investigate more.

[pouleyKetchoupp]

To fix the bug you mentioned I think this line:

String full_text = _base_get_text(cursor.line, 0, cursor.line, text[cursor.line].length());

Can be replaced with:

String full_text = _base_get_text(0, 0, cursor.line, cursor.column);

Apart from that it seems to work fine now!

[naithar]

To fix the bug you mentioned I think this line:

String full_text = _base_get_text(cursor.line, 0, cursor.line, text[cursor.line].length());

Can be replaced with:

String full_text = _base_get_text(0, 0, cursor.line, cursor.column);

Apart from that it seems to work fine now!

Yup, I'm waiting for a build to test it right now :)

Edit:

Seems to be fixed now with latest commit.

[pouleyKetchoupp]

On Android, this PR also fixes the same issues #38309 did for LineEdit on TextEdit.

[akien-mga]

Thanks!