Initial Commit

lib/modal_progress_hud_nsn.dart

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+library modal_progress_hud;
+
+import 'package:flutter/material.dart';
+
+///
+/// Wrap around any widget that makes an async call to show a modal progress
+/// indicator while the async call is in progress.
+///
+/// The progress indicator can be turned on or off using [inAsyncCall]
+///
+/// The progress indicator defaults to a [CircularProgressIndicator] but can be
+/// any kind of widget
+///
+/// The progress indicator can be positioned using [offset] otherwise it is
+/// centered
+///
+/// The modal barrier can be dismissed using [dismissible]
+///
+/// The color of the modal barrier can be set using [color]
+///
+/// The opacity of the modal barrier can be set using [opacity]
+///
+/// HUD=Heads Up Display
+///
+class ModalProgressHUD extends StatelessWidget {
+  final bool inAsyncCall;
+  final double opacity;
+  final Color color;
+  final Widget progressIndicator;
+  final Offset offset;
+  final bool dismissible;
+  final Widget child;
+
+  ModalProgressHUD({
+    Key key,
+    @required this.inAsyncCall,
+    this.opacity = 0.3,
+    this.color = Colors.grey,
+    this.progressIndicator = const CircularProgressIndicator(),
+    this.offset,
+    this.dismissible = false,
+    @required this.child,
+  })  : assert(child != null),
+        assert(inAsyncCall != null),
+        super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    if (!inAsyncCall) return child;
+
+    Widget layOutProgressIndicator;
+    if (offset == null)
+      layOutProgressIndicator = Center(child: progressIndicator);
+    else {
+      layOutProgressIndicator = Positioned(
+        child: progressIndicator,
+        left: offset.dx,
+        top: offset.dy,
+      );
+    }
+
+    return new Stack(
+      children: [
+        child,
+        new Opacity(
+          child: new ModalBarrier(dismissible: dismissible, color: color),
+          opacity: opacity,
+        ),
+        layOutProgressIndicator,
+      ],
+    );
+  }
+}