app, io: [wasm, android] add support for numeric/email keyboard mode

Previously, the on-screen keyboard always displays the text keyboard,
(QWERTY or equivalent).

For optimal user experience, it's possible to specify the keyboard type
using `InputHint`. The on-screen keyboard will provide shortcuts or
restrict what the user can input.

Due to some limitations (gio#116), only numeric and text keyboards are
supported on Android.

Signed-off-by: Inkeliz <inkeliz@inkeliz.com>

app/internal/wm/os_js.go

@@ -313,6 +313,27 @@ func (w *window) focus() {
 	w.requestFocus = true
 }
 
+func (w *window) keyboard(hint key.InputHint) {
+	var m string
+	switch hint {
+	case key.HintAny:
+		m = "text"
+	case key.HintText:
+		m = "text"
+	case key.HintNumeric:
+		m = "decimal"
+	case key.HintEmail:
+		m = "email"
+	case key.HintURL:
+		m = "url"
+	case key.HintTelephone:
+		m = "tel"
+	default:
+		m = "text"
+	}
+	w.tarea.Set("inputMode", m)
+}
+
 func (w *window) keyEvent(e js.Value, ks key.State) {
 	k := e.Get("key").String()
 	if n, ok := translateKey(k); ok {
@@ -524,6 +545,10 @@ func (w *window) ShowTextInput(show bool) {
 	}()
 }
 
+func (w *window) SetInputHint(mode key.InputHint) {
+	w.keyboard(mode)
+}
+
 // Close the window. Not implemented for js.
 func (w *window) Close() {}