Crop() widget not working

[filipppp]

When try to use the widget with and without the aspectRation property, it always fails with a BoxConstraint.

`════════ Exception caught by rendering library ═════════════════════════════════════════════════════
The following assertion was thrown during performLayout():
BoxConstraints forces an infinite height.

These invalid constraints were provided to RenderSemanticsGestureHandler's layout() function by the following function, which probably computed the invalid constraints in question:
RenderConstrainedBox.performLayout (package:flutter/src/rendering/proxy_box.dart:259:13)
The offending constraints were: BoxConstraints(w=411.4, h=Infinity)
User-created ancestor of the error-causing widget was:
Crop-[LabeledGlobalKey#45848] file:///C:/Users/Filip/Desktop/Projekte/Diplomarbeit/listassist/lib/pages/picture-show.dart:182:15
When the exception was thrown, this was the stack:
#0 BoxConstraints.debugAssertIsValid..throwError (package:flutter/src/rendering/box.dart:501:9)
#1 BoxConstraints.debugAssertIsValid. (package:flutter/src/rendering/box.dart:548:21)
#2 BoxConstraints.debugAssertIsValid (package:flutter/src/rendering/box.dart:552:6)
#3 RenderObject.layout (package:flutter/src/rendering/object.dart:1618:24)
#4 RenderConstrainedBox.performLayout (package:flutter/src/rendering/proxy_box.dart:259:13)
...
The following RenderObject was being processed when the exception was fired: RenderConstrainedBox#a9775 relayoutBoundary=up3 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
... parentData: offset=Offset(0.0, 0.0); flex=null; fit=null (can use size)
... constraints: BoxConstraints(0.0<=w<=411.4, 0.0<=h<=Infinity)
... size: MISSING
... additionalConstraints: BoxConstraints(biggest)
RenderObject: RenderConstrainedBox#a9775 relayoutBoundary=up3 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
parentData: offset=Offset(0.0, 0.0); flex=null; fit=null (can use size)
constraints: BoxConstraints(0.0<=w<=411.4, 0.0<=h<=Infinity)
size: MISSING
additionalConstraints: BoxConstraints(biggest)
... child: RenderSemanticsGestureHandler#ae6f2 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
... parentData:
... constraints: MISSING
... size: MISSING
... gestures:
... child: RenderPointerListener#10954 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
... parentData:
... constraints: MISSING
... size: MISSING
... behavior: opaque
... listeners: down
... child: RenderCustomPaint#82cbb NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
... parentData:
... constraints: MISSING
... size: MISSING
════════════════════════════════════════════════════════════════════════════════════════════════════

════════ (2) Exception caught by rendering library ═════════════════════════════════════════════════
RenderBox was not laid out: RenderConstrainedBox#a9775 relayoutBoundary=up3 NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
'package:flutter/src/rendering/box.dart':
Failed assertion: line 1681 pos 12: 'hasSize'
User-created ancestor of the error-causing widget was:
Center file:///C:/Users/Filip/Desktop/Projekte/Diplomarbeit/listassist/lib/pages/picture-show.dart:148:13
════════════════════════════════════════════════════════════════════════════════════════════════════`

My code:

            if (_imageFile != null) ...[
              Crop(
                key: cropKey,
                image: FileImage(_imageFile),
                aspectRatio: 4.0 / 3.0,
              ),
            ]

[lykhonis]

You need to make sure the widget is wrapped by some container that enforces size.