add draggable in js & android

doric-demo/src/DraggableDemo.ts

@@ -0,0 +1,30 @@
+import { Panel, Group, vlayout, layoutConfig, draggable, Color, Text} from "doric";
+import { title } from "./utils";
+@Entry
+class DraggableDemo extends Panel {
+    build(root: Group) {
+        let text = (new Text).also(it => {
+            it.layoutConfig = layoutConfig().most()
+            it.textColor = Color.parse('#ff0000')
+        })
+        vlayout([
+            title("Draggable Demo"),
+            draggable({
+                onDrag: (x: number, y: number) => {
+                    text.text = "x: " + x + " y: " + y
+                }
+            }, [ text ]).apply({
+                layoutConfig: layoutConfig().just(),
+                width: 100,
+                height: 100,
+                backgroundColor: Color.WHITE
+            })
+        ])
+            .apply({
+                layoutConfig: layoutConfig().most(),
+                backgroundColor: Color.BLACK
+            })
+            .in(root)
+    }
+
+}