Android Studio 上的 AVD 中不会显示按钮

Question

I'm new to Android Studio and i have been trying to get the button to work but on my device it wouldn't show but on my design page it's there but no errors show up.

the design layout

the code

the AVD

Answer 1

Remove either layout_marginTop or layout_constraintVertical_bias attribute from the Button, according to the design requirements. Bias moves the button to the very bottom of the screen, and margin moves it event lower, out of the visible are.

PS do not trust AS layout preview, it lies sometimes:)