Function view_holder_set_back_callback 

pub unsafe extern "C" fn view_holder_set_back_callback(
    view_holder: *mut ViewHolder,
    back_callback: BackCallback,
    back_context: *mut c_void,
)

Set the back key callback.

The callback function will be called if the user has pressed the Back key and the current view did not handle this event.

Arguments

• view_holder - ViewHolder instance
• back_callback - pointer to the callback function
• back_context - pointer to a user-specific object, can be NULL