Flutter dynamic height example

• Using IntrinsicHeight:

The IntrinsicHeight widget determines its own height by aggregating the sizes of its children. This widget may be used to dynamically determine the height of your wrapped content.

Example:

IntrinsicHeight(
  child: Row(
    children: [
      Container(
        child: ...
      ),
      Container(
        child: ...
      ),
    ],
  ),
)

Both containers’ heights will be dynamically determined by the items they hold, and they will be a uniform height.

• Using Custom Constraints:

The widget’s height can be modified to your specifications with the help of user-defined constraints. This approach, however, may necessitate a specialized widget and a deeper understanding of Flutter. As a rule, Flutter provides a plethora of options for establishing dynamic height. Your use case and requirements will determine the best approach.

• Using SingleChildScrollView:

A SingleChildScrollView can be used to encapsulate a widget whose content is too vast to fit on a single screen. Users can scroll over the content with this widget, which automatically adapts its height to the volume being displayed.

Example:

SingleChildScrollView(
  child: Column(
    children: [
      Container(
        child: ...
      ),
      Container(
        child: ...
      ),
    ],
  ),
)

In this example, the user can scroll over the two containers’ content, which will modify the widget’s height.

• Using Expanded with Flex:

An Expanded widget can be used in conjunction with a Flex widget to modify the widget’s height within the Flex container. The height of the Expanded widget will be adjusted such that it fills the entire Flex container.

Example dynamic height flutter using Flex:

Flex(
  direction: Axis.vertical,
  children: [
    Expanded(
      child: Container(
        child: ...
      ),
    ),
    Expanded(
      child: Container(
        child: ...
      ),
    ),
  ],
)

In this case, the Flex container will be changed such that both containers are the same height and may fit inside.

In Flutter, you can get responsive height in a few different methods. The needs at hand and the nature of the material will determine the method most appropriate.

• Using LayoutDelegate:

A LayoutDelegate can be used if granular manipulation of the widget’s layout is required. If you want to set up unique constraints and coordinates for your widget, you may do so by creating a LayoutDelegate, a custom class that extends the SingleChildLayoutDelegate class.

Example dynamic height flutter using LayoutDelegate:

class CustomLayoutDelegate extends SingleChildLayoutDelegate {
  @override
  BoxConstraints getConstraintsForChild(BoxConstraints constraints) {
    return BoxConstraints(
      minHeight: 100,
      maxHeight: 200,
    );
  }

  @override
  Offset getPositionForChild(Size size, Size childSize) {
    return Offset(0, 0);
  }

  @override
  bool shouldRelayout(covariant SingleChildLayoutDelegate oldDelegate) {
    return false;
  }
}

Container(
  child: CustomSingleChildLayout(
    delegate: CustomLayoutDelegate(),
    child: ...
  ),
)

In this example, the CustomLayoutDelegate defines a minimum and maximum height for the widget and positions it at the top-left corner. The CustomSingleChildLayout widget uses this delegate to layout its child widget.

• Using ConstrainedBox:

The ConstrainedBox widget is useful when the height of a widget must be limited to a predefined range. The height of this widget can be constrained between a minimum and a maximum value that you specify.

Example:

ConstrainedBox(
  constraints: BoxConstraints(
    minHeight: 100,
    maxHeight: 200,
  ),
  child: ...
)

Here, we’ll say the widget can’t be any shorter than 100 pixels or any taller than 200 pixels.

These are supplementary dynamic height attainment strategies for Flutter. The best method to employ is the one that fits your needs and goals best.

• Using Custom MultiChildLayoutDelegate:

If you need to position multiple children within a parent widget and adjust their height based on the available space or content size, you can use a Custom MultiChildLayoutDelegate. This approach requires more advanced knowledge of Flutter and may require creating a custom widget.

Example dynamic height flutter using MultiChildLayoutDelegate:

class CustomMultiChildLayoutDelegate extends MultiChildLayoutDelegate {
  @override
  void performLayout(Size size) {
    //position and layout children here
  }

  @override
  bool shouldRelayout(covariant MultiChildLayoutDelegate oldDelegate) {
    return false;
  }
}

CustomMultiChildLayout(
  delegate: CustomMultiChildLayoutDelegate(),
  children: [
    LayoutId(
      id: 'child1',
      child: Container(
        child: ...
      ),
    ),
    LayoutId(
      id: 'child2',
      child: Container(
        child: ...
      ),
    ),
  ],
)

In this example, the CustomMultiChildLayoutDelegate defines the layout and positioning of the child widgets. The CustomMultiChildLayout widget uses this delegate to layout its child widgets.

There are several alternative methods for achieving responsive height in Flutter. The optimal approach will vary based on your unique use case and specific requirements.

Conclusion

Flutter widgets’ dynamic height adjusts to their parent widget’s space. This helps with designing responsive layouts for different screen sizes and orientations.

Flutter supports dynamic height utilizing LayoutBuilder widgets, MediaQuery classes, and Expanded widgets. Each solution has pros and cons depending on the use case.

Flutter’s dynamic height is a valuable tool for developing flexible, adaptable user interfaces that work well across devices and screen sizes.