Common errors encounters in App Development in Flutter!
Several frequently-encountered Flutter framework errors
‘A RenderFlex overflowed…’
RenderFlex overflow is one of the most frequently encountered Flutter framework errors, and you probably have run into it already.
What does the error look like?
When it happens, you’ll see yellow & black stripes indicating the area of overflow in the app UI in addition to the error message in the debug console:
The following assertion was thrown during layout:
A RenderFlex overflowed by 1146 pixels on the right.The relevant error-causing widget was
Row lib/errors/renderflex_overflow_column.dart:23
The overflowing RenderFlex has an orientation of Axis.horizontal.
The edge of the RenderFlex that is overflowing has been marked in the rendering
with a yellow and black striped pattern. This is usually caused by the contents
being too big for the RenderFlex.
(Additional lines of this message omitted)
‘RenderBox was not laid out’
While this error is pretty common, it’s often a side effect of a primary error occurring earlier in the rendering pipeline.
What does the error look like?
The message shown by the error looks like this:
RenderBox was not laid out:
RenderViewport#5a477 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE‘Vertical viewport was given unbounded height’
This is another common layout error you could run into while creating a UI in your Flutter app.
What does the error look like?
The message shown by the error looks like this:
The following assertion was thrown during performResize():
Vertical viewport was given unbounded height.Viewports expand in the scrolling direction to fill their container.
In this case, a vertical viewport was given an unlimited amount of
vertical space in which to expand. This situation typically happens when a
scrollable widget is nested inside another scrollable widget.
(Additional lines of this message omitted)
‘An InputDecorator…cannot have an unbounded width’
The error message suggests that it’s also related to box constraints, which are important to understand to avoid many of the most common Flutter framework errors.
What does the error look like?
The message shown by the error looks like this:
The following assertion was thrown during performLayout():
An InputDecorator, which is typically created by a TextField, cannot have an
unbounded width.
This happens when the parent widget does not provide a finite width constraint.
For example, if the InputDecorator is contained by a `Row`, then its width must
be constrained. An `Expanded` widget or a SizedBox can be used to constrain the
width of the InputDecorator or the TextField that contains it.
(Additional lines of this message omitted)‘Incorrect use of ParentData widget’
This error is about missing an expected parent widget.
What does the error look like?
The message shown by the error looks like this:
The following assertion was thrown while looking for parent data:
Incorrect use of ParentDataWidget.
(Some lines of this message omitted)
Usually, this indicates that at least one of the offending ParentDataWidgets
listed above is not placed directly inside a compatible ancestor widget.‘setState called during build’
The build method in your Flutter code is not a good place to call setState either directly or indirectly.
What does the error look like?
When the error occurs, the following message gets displayed in the console:
The following assertion was thrown building DialogPage(dirty, dependencies:
[_InheritedTheme, _LocalizationsScope-[GlobalKey#59a8e]],
state: _DialogPageState#f121e):
setState() or markNeedsBuild() called during build.This Overlay widget cannot be marked as needing to build because the framework
is already in the process of building widgets.
(Additional lines of this message omitted)
