# Flutter contextual action bar(CAB) ![](https://raw.githubusercontent.com/De-Morgan/flutter-contextual-action-bar/master/screenshots/whatsApp.gif) # CAB & Flutter CAB is a top app bar that replace the application app bar to provide contextual actions to selected items. Check the material implementation and requirement [here](https://material.io/components/app-bars-top#contextual-action-bar) Flutter does not natively support CAB yet. see [issue](https://github.com/flutter/flutter/issues/44464) Until CAB is natively supported, this package should provide you with an elegant way to implement the contextual action bar in flutter. ## How it works - `ContextualScaffold` - `ContextualAppBar` - `ContextualAction` - `ContextualActionWidget` ## `ContextualScaffold` The `ContextualScaffold` is similar to the normal material `Scaffold` except that it also takes a required `contextualAppBar`. ``` ContextualScaffold( contextualAppBar: ContextualAppBar(), appBar: AppBar(), body: Body(), ) ``` You can provide multiple `ContextualScaffold` as needed ## `ContextualAppBar` The `ContextualAppBar` is similar to the normal material `Appbar` but takes a `counterBuilder` instead of `title` and also a `contextualActions` instead of `actions`. ``` ContextualAppBar( counterBuilder: (int itemsCount){ return Text("$itemsCount Selected"); }, contextualActions: [], ) ``` ## `ContextualAction` The `ContextualAction` allows you to take actions on the selected items, with the help of `itemsHandler` callback. ``` ContextualAction( itemsHandler: (List items) { items.forEach((item) { Scaffold.of(context).showSnackBar(SnackBar( content: Text("$item saved"), )); }); }, child: Icon(Icons.save), ), ``` ## `ContextualActionWidget` You can use the `ContextualActionWidget` anywhere in the `ContextualActionScaffold` body to notify `ContextualActionScaffold` that an item have been selected in order to show the `ContextualAppBar`. ``` ContextualActionWidget( data: ?, child: ChildWidget(), ) ``` *Note: It is important that the child widget does not handle onLongPress.* ## A closer look at `ContextualActionWidget` The `ContextualActionWidget` takes other optional parameters like - `selectedColor` - `selectedWidget` - `unselectedWidget` The `selectedColor` is the color of the background for the selected item, it defaults to the splash color, if not provided. The `selectedColor` works well with `ListTile`. `selectedWidget` and `unselectedWidget` are `stacked` on top of the provided child widget. By default, they are positioned at the center of the provided child widget. Since They are stacked, you can use `Row`, `Align`, `Positioned` Widget or any other combination of widgets to position them where desired. The `selectedWidget` is shown when the `ActionMode` is enabled and the item is selected, while the `unselectedWidget` is shown when `ActionMode` is enabled and the item is not selected. See example(status_saver) image below with both the `selectedWidget` and `unselectedWidget` aligned to the top-right corner. ![](https://raw.githubusercontent.com/De-Morgan/flutter-contextual-action-bar/master/screenshots/status_saver.png) ## ActionMode This contextual action bar workaround does not support zero item in the `ActionMode`. - Use the `ActionMode.addItem` to add an item to the selected items. If this is the first selection, the `ActionMode` is will be enabled. - Use the `ActionMode.addItems` to add a list of items. - Use the `ActionMode.disable` to disable and deselect all selected items. - Use the `ActionMode.enabledStream` to emit true or false depending on if the Action mode is enabled or disabled respectively. *Note: In most cases, you won't need to use `ActionMode.disable` because the package already do that for you where needed.* ***Study complete examples at [example page](https://github.com/De-Morgan/flutter-contextual-action-bar/blob/master/example/lib/main.dart)***. **If you like the project, don't forget to star ⭐️** ### Other Packages authored by me - [loadinglistview](https://pub.dev/packages/loadinglistview#-readme-tab-) ## License This package is licensed under the MIT license. See [LICENSE](https://github.com/De-Morgan/flutter-contextual-action-bar/blob/master/LICENSE) for details.

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