How do I how do I lock the screen not to reduce

I am having problem in Textbox . When the user selects the TextBox appears the keyboard and the screen is reduced.

I wish the keyboard was displayed , but the screen is still the same size.

How to do it?

I get the same issue and am thinking about putting some clickable letters on screen instead of allowing keyboard input. Then show the input onscreen in something that just LOOKS like a Textbox.

other solution ?