invalidate the canvas after every touch event

app/src/main/java/draw/simplemobiletools/com/MyCanvas.java

@@ -66,20 +66,19 @@ public class MyCanvas extends View {
                 startX = x;
                 startY = y;
                 actionDown(x, y);
-                invalidate();
                 break;
             case MotionEvent.ACTION_MOVE:
                 actionMove(x, y);
-                invalidate();
                 break;
             case MotionEvent.ACTION_UP:
                 actionUp();
-                invalidate();
                 break;
             default:
                 break;
         }
 
+        invalidate();
+
         return true;
     }
 }