app: [android] ensure a new frame is always scheduled when visible and animating

Possible fix to #614.

References: https://todo.sr.ht/~eliasnaur/gio/614
Signed-off-by: Elias Naur <mail@eliasnaur.com>

app/os_android.go

@@ -575,10 +575,7 @@ func Java_org_gioui_GioView_onFrameCallback(env *C.JNIEnv, class C.jclass, view
 	if !exist {
 		return
 	}
-	if w.visible && w.animating {
-		w.draw(env, false)
-		callVoidMethod(env, w.view, gioView.postFrameCallback)
-	}
+	w.draw(env, false)
 }
 
 //export Java_org_gioui_GioView_onBack
@@ -882,6 +879,9 @@ func (w *window) draw(env *C.JNIEnv, sync bool) {
 		},
 		Sync: sync,
 	})
+	if w.animating {
+		callVoidMethod(env, w.view, gioView.postFrameCallback)
+	}
 	a11yActive, err := callBooleanMethod(env, w.view, gioView.isA11yActive)
 	if err != nil {
 		panic(err)