Added SetFocus() to Form which changes the focus to a specific form element. Resolves #286

form.go

@@ -154,6 +154,20 @@ func (f *Form) SetButtonTextColor(color tcell.Color) *Form {
 	return f
 }
 
+// SetFocus shifts the focus to the form element with the given index, counting
+// non-button items first and buttons last. Note that this index is only used
+// when the form itself receives focus.
+func (f *Form) SetFocus(index int) *Form {
+	if index < 0 {
+		f.focusedElement = 0
+	} else if index >= len(f.items)+len(f.buttons) {
+		f.focusedElement = len(f.items) + len(f.buttons)
+	} else {
+		f.focusedElement = index
+	}
+	return f
+}
+
 // AddInputField adds an input field to the form. It has a label, an optional
 // initial value, a field width (a value of 0 extends it as far as possible),
 // an optional accept function to validate the item's value (set to nil to