A Flutter implementation of an expandable and animated floating search bar

Flutterappworld

4 years ago

Material Floating Search Bar

A Flutter implementation of an expandable floating search bar, also known as persistent search, similar to the ones used extensively by Google in their own apps.

Click here to view the full example.

Installing

Add it to your pubspec.yaml file:

dependencies:
  material_floating_search_bar: ^0.3.4

Install packages from the command line

flutter packages get

If you like this package, consider supporting it by giving it a star on GitHub and a like on pub.dev

Usage

A FloatingSearchBar should be placed above your main content in your widget tree and be allowed to fill all the available space.

@override
Widget build(BuildContext context) {
  return Scaffold(
    // This is handled by the search bar itself.
    resizeToAvoidBottomInset: false,
    body: Stack(
      fit: StackFit.expand,
      children: [
        buildMap(),
        buildBottomNavigationBar(),
        buildFloatingSearchBar(),
      ],
    ),
  );
}

Widget buildFloatingSearchBar() {
  final isPortrait = MediaQuery.of(context).orientation == Orientation.portrait;

  return FloatingSearchBar(
    hint: 'Search...',
    scrollPadding: const EdgeInsets.only(top: 16, bottom: 56),
    transitionDuration: const Duration(milliseconds: 800),
    transitionCurve: Curves.easeInOut,
    physics: const BouncingScrollPhysics(),
    axisAlignment: isPortrait ? 0.0 : -1.0,
    openAxisAlignment: 0.0,
    width: isPortrait ? 600 : 500,
    debounceDelay: const Duration(milliseconds: 500),
    onQueryChanged: (query) {
      // Call your model, bloc, controller here.
    },
    // Specify a custom transition to be used for
    // animating between opened and closed stated.
    transition: CircularFloatingSearchBarTransition(),
    actions: [
      FloatingSearchBarAction(
        showIfOpened: false,
        child: CircularButton(
          icon: const Icon(Icons.place),
          onPressed: () {},
        ),
      ),
      FloatingSearchBarAction.searchToClear(
        showIfClosed: false,
      ),
    ],
    builder: (context, transition) {
      return ClipRRect(
        borderRadius: BorderRadius.circular(8),
        child: Material(
          color: Colors.white,
          elevation: 4.0,
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: Colors.accents.map((color) {
              return Container(height: 112, color: color);
            }).toList(),
          ),
        ),
      );
    },
  );
}

Usage with `Scrollables`

By default, the Widget returned by the builder is not allowed to have an unbounded (infinite) height. This is necessary in order for the search bar to be able to dismiss itself, when the user taps below the area of the child. (For example, when you have a list of items but there are not enough items to fill the whole screen, as shown in the gifs above, the user would expect to be able to close the search bar when tapping below the last item in the list).

Therefore, shrinkWrap should be set to true on all Scrollables and physics to NeverScrollableScrollPhysics. On Columns, the mainAxisSize should be set to MainAxisSize.min.

If you don’t want this behavior, you can set the isScrollControlled flag to true. Then you are allowed to use expanding Widgets such as Scrollables with the caveat that the search bar may not be able to detect taps on the backdrop area.

Customizations

There are many customization options:

Field	Description
`body`	The widget displayed below the `FloatingSearchBar`. This is useful, if the `FloatingSearchBar` should react to scroll events (i.e. hide from view when a `Scrollable` is being scrolled down and show it again when scrolled up). See here for more info.
`accentColor`	The color used for elements such as the progress indicator. Defaults to the themes accent color if not specified.
`backgroundColor`	The color of the card. If not specified, defaults to `theme.cardColor`.
`shadowColor`	The color of the shadow drawn when `elevation > 0`. If not specified, defaults to `Colors.black54`.
`iconColor`	When specified, overrides the themes icon color for this `FloatingSearchBar`, for example to easily adjust the icon color for all `actions` and `leadingActions`.
`backdropColor`	The color that fills the available space when the `FloatingSearchBar` is opened. Typically a black-ish color. If not specified, defaults to `Colors.black26`.
`margins`	The insets from the edges of its parent. This can be used to position the `FloatingSearchBar`. If not specifed, the `FloatingSearchBar` will try to position itself at the top offsetted by `MediaQuery.of(context).viewPadding.top` to avoid the status bar.
`padding`	The padding of the card. Only the horizontal values will be honored.
`insets`	The padding between `leadingActions`, the input field and `actions` respectively. Only the horizontal values will be honored.
`height`	The height of the card. If not specified, defaults to `48.0` pixels.
`elevation`	The elevation of the card.
`width`	The width of the `FloatingSearchBar`. By default the `FloatingSearchBar` will expand to fill all the available width. This value can be set to avoid this.
`openWidth`	The width of the `FloatingSearchBar` when opened. This can be used, when the max width when opened should be different from the one specified by `maxWidth`. When not specified, will use the value of `maxWidth`.
`axisAlignment`	How the `FloatingSearchBar` should be aligned when the available width is bigger than the width specified by `maxWidth`. When not specified, defaults to `0.0` which centers the `FloatingSearchBar`.
`openAxisAlignment`	How the `FloatingSearchBar` should be aligned when the available width is bigger than the width specified by `openMaxWidth`. When not specified, will use the value of `axisAlignment`.
`border`	The border of the card.
`borderRadius`	The `BorderRadius` of the card. When not specified, defaults to `BorderRadius.circular(4)`.
`hintStyle`	The `TextStyle` for the hint in the `TextField`.
`queryStyle`	The `TextStyle` for the input in the `TextField`.
`clearQueryOnClose`	Whether the current query should be cleared when the `FloatingSearchBar` was closed. When not specifed, defaults to `true`.
`automaticallyImplyDrawerHamburger`	Whether a hamburger menu should be shown when there is a `Scaffold` with a `Drawer` in the widget tree.
`closeOnBackdropTap`	Whether the `FloatingSearchBar` should be closed when the backdrop was tapped. When not specified, defaults to `true`.
`automaticallyImplyBackButton`	Whether to automatically display a back button if the enclosing route can be popped. When not specified, defaults to `true`.
`progress`	The progress of the `LinearProgressIndicator` inside the card. When set to a `double` between `0..1`, will show show a determined `LinearProgressIndicator`. When set to `true`, the `FloatingSearchBar` will show an indetermined `LinearProgressIndicator`. When `null` or `false`, will hide the `LinearProgressIndicator`.
`transitionDuration`	The duration of the animation between opened and closed state.
`transitionCurve`	The curve for the animation between opened and closed state.
`debounceDelay`	The delay between the time the user stopped typing and the invocation of the `onQueryChanged` callback. This is useful for example if you want to avoid doing expensive tasks, such as making a network call, for every single character.
`title`	A widget that is shown in place of the `TextField` when the `FloatingSearchBar` is closed.
`hint`	The text value of the hint of the `TextField`.
`actions`	A list of widgets displayed in a row after the `TextField`. Consider using `FloatingSearchBarActions` for more advanced actions that can interact with the `FloatingSearchBar`. In LTR languages, they will be displayed to the left of the `TextField`.
`leadingActions`	A list of widgets displayed in a row before the `TextField`. Consider using `FloatingSearchBarActions` for more advanced actions that can interact with the `FloatingSearchBar`. In LTR languages, they will be displayed to the right of the `TextField`.
`onQueryChanged`	A callback that gets invoked when the input of the query inside the `TextField` changed.
`onSubmitted`	A callback that gets invoked when the user submitted their query (e.g. hit the search button).
`onFocusChanged`	A callback that gets invoked when the `FloatingSearchBar` receives or looses focus.
`transition`	The transition to be used for animating between closed and opened state. See below for a list of all available transitions.
`builder`	The builder for the body of this `FloatingSearchBar`. Usually, a list of items. Note that unless `isScrollControlled` is set to `true`, the body of a `FloatingSearchBar` must not have an unbounded height meaning that `shrinkWrap` should be set to `true` on all `Scrollables`.
`controller`	The controller for this `FloatingSearchBar` which can be used to programatically open, close, show or hide the `FloatingSearchBar`.
`isScrollControlled`	Whether the body of this `FloatingSearchBar` is using its own `Scrollable`. This will allow the body of the `FloatingSearchBar` to have an unbounded height. Note that when set to `true`, the `FloatingSearchBar` won’t be able to dismiss itself when tapped below the height of child inside the `Scrollable`, when the child is smaller than the avaialble height.

Transitions

As of now there are three types of transitions that are exemplified above:

Transition	Description
`CircularFloatingSearchBarTransition`	Clips its child in an expanding circle.
`ExpandingFloatingSearchBarTransition`	Fills all the available space with the background of the `FloatingSearchBar`. Similar to the ones used in many Google apps like Gmail.
`SlideFadeFloatingSearchBarTransition`	Vertically slides and fades its child.

You can also easily create you own custom transition by extending FloatingSearchBarTransition.

Scrolling

A common behavior for floating search bars is to disappear when the user scrolls a Scrollable down and appear again when scrolling up. This can be easily achieved by passing your Widget to the body field of FloatingSearchBar. This way FloatingSearchBar can listen for ScrollNotifications. In order that the FloatingSearchBar doesn’t interact with every Scrollable below in the widget tree, you should wrap every Scrollable that should interact with the FloatingSearchBar inside a FloatingSearchBarScrollNotifier.

Example

class Home extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return FloatingSearchBar(
      // Your pages or just a simple Scaffold...
      body: IndexedStack(
        children: [
          MyAwesomePage(),
        ],
      ),
    );
  }
}

class MyAwesomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    /// Wrap your Scrollable in a FloatingSearchBarScrollNotifier
    /// to indicate that the FloatingSearchBar should react to
    /// scroll events from this Scrollable.
    return FloatingSearchBarScrollNotifier(
      child: ListView.builder(
        itemCount: 42,
        itemBuilder: (_, index) => Item('Item $index'),
      ),
    );
  }
}

Floating Search App Bar

Sometimes a FloatingSearchBar might not be the most appriopriate search method for your use case. For this reason there is also the FloatingSearchAppBar. It is a normal AppBar with easy search integration very similar to the normal FloatingSearchBar.

Additional Customizations

In addition to most of the fields from the FloatingSearchBar, FloatingSearchAppBar has the following additional fields:

Field	Description
`colorOnScroll`	The color of the bar when a `Scrollable` inside the `body` was scrolled (i.e. the `Scrollable` is not at the top)
`liftOnScrollElevation`	The elevation of the bar when a `Scrollable` inside the `body` was scrolled (i.e. the `Scrollable` is not at the top)
`alwaysOpened`	Whether the bar should be always in opened state. This is useful for example, if you have a page dedicated only for search.
`hideKeyboardOnDownScroll`	Hides the keyboard a `Scrollable` inside the `body` was scrolled and shows it again when the user scrolls to the top.

Download Material Floating Search Bar Widget source code on GitHub

https://github.com/bnxm/material_floating_search_bar