flutter 如何将多个statefulWidget显示 - 知否问答 - 万象云+社区

import 'package:flutter/material.dart'; import 'package:flutter_swiper/flutter_swiper.dart'; class HomeView extends StatelessWidget { @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar( title: Text('Home'), ), body: Column( children: <Widget>[ Text('1'), Text('2'), Text('3'), Text('4'), GetHttp(), GetBanner(), ], ), ); } } class GetHttp extends StatefulWidget { @override _GetHttpState createState() => _GetHttpState(); } class _GetHttpState extends State<GetHttp> { @override Widget build(BuildContext context) { return GridView.count( crossAxisCount: 2, children: <Widget>[ Container( child: Image.asset('images/swipe_1.jpeg',fit: BoxFit.cover,), ), Container( child: Image.asset('images/swipe_2.jpeg',fit: BoxFit.cover,), ), Container( child: Image.asset('images/swipe_3.jpeg',fit: BoxFit.cover,), ), Container( child: Image.asset('images/swipe_4.jpeg',fit: BoxFit.cover,), ), ], ); } } // 轮播图 class GetBanner extends StatefulWidget { @override _GetBannerState createState() => _GetBannerState(); } class _GetBannerState extends State<GetBanner> { @override Widget build(BuildContext context) { return Container( child: Swiper( itemBuilder: (BuildContext context, int index) { return new Image.asset('images/swipe_${index+1}.jpeg', fit: BoxFit.fill,); }, itemCount: 4, pagination: new SwiperPagination(), control: new SwiperControl( iconPrevious: null, iconNext: null, ), ) ); } }

Performing hot reload... ⣻flutter: ══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════ flutter: The following assertion was thrown during performResize(): flutter: Vertical viewport was given unbounded height. flutter: Viewports expand in the scrolling direction to fill their container.In this case, a vertical flutter: viewport was given an unlimited amount of vertical space in which to expand. This situation flutter: typically happens when a scrollable widget is nested inside another scrollable widget. flutter: If this widget is always nested in a scrollable widget there is no need to use a viewport because flutter: there will always be enough vertical space for the children. In this case, consider using a Column flutter: instead. Otherwise, consider using the "shrinkWrap" property (or a ShrinkWrappingViewport) to size flutter: the height of the viewport to the sum of the heights of its children. flutter: flutter: Widget creation tracking is currently disabled. Enabling it enables improved error messages. It can flutter: be enabled by passing `--track-widget-creation` to `flutter run` or `flutter test`. flutter: flutter: When the exception was thrown, this was the stack: flutter: #0 RenderViewport.performResize.<anonymous closure> (package:flutter/src/rendering/viewport.dart:1165:15) flutter: #1 RenderViewport.performResize (package:flutter/src/rendering/viewport.dart:1218:6) flutter: #2 RenderObject.layout (package:flutter/src/rendering/object.dart:1686:9) flutter: #3 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #4 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #5 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #6 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #7 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #8 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #9 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #10 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #11 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #12 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #13 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #14 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #15 RenderFlex.performLayout (package:flutter/src/rendering/flex.dart:744:15) flutter: #16 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #17 MultiChildLayoutDelegate.layoutChild (package:flutter/src/rendering/custom_layout.dart:142:11) flutter: #18 _ScaffoldLayout.performLayout (package:flutter/src/material/scaffold.dart:444:7) flutter: #19 MultiChildLayoutDelegate._callPerformLayout (package:flutter/src/rendering/custom_layout.dart:212:7) flutter: #20 RenderCustomMultiChildLayoutBox.performLayout (package:flutter/src/rendering/custom_layout.dart:356:14) flutter: #21 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #22 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #23 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #24 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #25 _RenderCustomClip.performLayout (package:flutter/src/rendering/proxy_box.dart:1232:11) flutter: #26 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #27 MultiChildLayoutDelegate.layoutChild (package:flutter/src/rendering/custom_layout.dart:142:11) flutter: #28 _ScaffoldLayout.performLayout (package:flutter/src/material/scaffold.dart:444:7) flutter: #29 MultiChildLayoutDelegate._callPerformLayout (package:flutter/src/rendering/custom_layout.dart:212:7) flutter: #30 RenderCustomMultiChildLayoutBox.performLayout (package:flutter/src/rendering/custom_layout.dart:356:14) flutter: #31 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #32 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #33 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #34 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #35 _RenderCustomClip.performLayout (package:flutter/src/rendering/proxy_box.dart:1232:11) flutter: #36 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #37 MultiChildLayoutDelegate.layoutChild (package:flutter/src/rendering/custom_layout.dart:142:11) flutter: #38 _ScaffoldLayout.performLayout (package:flutter/src/material/scaffold.dart:444:7) flutter: #39 MultiChildLayoutDelegate._callPerformLayout (package:flutter/src/rendering/custom_layout.dart:212:7) flutter: #40 RenderCustomMultiChildLayoutBox.performLayout (package:flutter/src/rendering/custom_layout.dart:356:14) flutter: #41 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #42 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #43 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #44 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #45 _RenderCustomClip.performLayout (package:flutter/src/rendering/proxy_box.dart:1232:11) flutter: #46 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #47 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #48 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #49 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #50 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #51 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #52 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #53 RenderStack.performLayout (package:flutter/src/rendering/stack.dart:510:15) flutter: #54 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #55 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #56 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #57 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #58 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #59 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #60 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #61 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #62 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #63 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #64 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #65 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #66 RenderOffstage.performLayout (package:flutter/src/rendering/proxy_box.dart:3140:13) flutter: #67 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #68 RenderStack.performLayout (package:flutter/src/rendering/stack.dart:510:15) flutter: #69 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #70 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #71 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #72 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #73 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #74 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #75 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #76 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #77 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #78 RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13) flutter: #79 RenderObject.layout (package:flutter/src/rendering/object.dart:1701:7) flutter: #80 RenderView.performLayout (package:flutter/src/rendering/view.dart:152:13) flutter: #81 RenderObject._layoutWithoutResize (package:flutter/src/rendering/object.dart:1578:7) flutter: #82 PipelineOwner.flushLayout (package:flutter/src/rendering/object.dart:844:18) flutter: #83 RendererBinding.drawFrame (package:flutter/src/rendering/binding.dart:341:19) flutter: #84 WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:761:13) flutter: #85 RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:280:5) flutter: #86 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1033:15) flutter: #87 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:975:9) flutter: #88 SchedulerBinding.scheduleWarmUpFrame.<anonymous closure> (package:flutter/src/scheduler/binding.dart:784:7) flutter: #90 _Timer._runTimers (dart:isolate-patch/timer_impl.dart:382:19) flutter: #91 _Timer._handleMessage (dart:isolate-patch/timer_impl.dart:416:5) flutter: #92 _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:172:12) flutter: (elided one frame from package dart:async-patch) flutter: flutter: The following RenderObject was being processed when the exception was fired: RenderViewport#3e402 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE: flutter: needs compositing flutter: creator: Viewport ← IgnorePointer-[GlobalKey#183b2] ← Semantics ← _PointerListener ← Listener ← flutter: _GestureSemantics ← RawGestureDetector-[LabeledGlobalKey<RawGestureDetectorState>#a4cde] ← flutter: _PointerListener ← Listener ← _ScrollableScope ← _ScrollSemantics-[GlobalKey#f52a7] ← Scrollable ← flutter: ⋯ flutter: parentData: <none> (can use size) flutter: constraints: BoxConstraints(0.0<=w<=414.0, 0.0<=h<=Infinity) flutter: layer: OffsetLayer#0ac41 DETACHED flutter: size: MISSING flutter: axisDirection: down flutter: crossAxisDirection: right flutter: offset: ScrollPositionWithSingleContext#d6235(offset: 0.0, range: null..null, viewport: null, flutter: ScrollableState, AlwaysScrollableScrollPhysics -> BouncingScrollPhysics, IdleScrollActivity#2245c, flutter: ScrollDirection.idle) flutter: anchor: 0.0 flutter: This RenderObject had the following descendants (showing up to depth 5): flutter: center child: RenderSliverPadding#48a7c NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE flutter: child: RenderSliverGrid#8bb85 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE flutter: ════════════════════════════════════════════════════════════════════════════════════════════════════ flutter: Another exception was thrown: RenderBox was not laid out: RenderViewport#3e402 NEEDS-LAYOUT NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE flutter: Another exception was thrown: RenderBox was not laid out: RenderViewport#3e402 NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE flutter: Another exception was thrown: RenderBox was not laid out: RenderIgnorePointer#bfb07 relayoutBoundary=up13 NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE flutter: Another exception was thrown: RenderBox was not laid out: RenderSemanticsAnnotations#96d37 relayoutBoundary=up12 NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE flutter: Another exception was thrown: RenderBox was not laid out: RenderPointerListener#073bd relayoutBoundary=up11 NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE flutter: Another exception was thrown: RenderBox was not laid out: RenderSemanticsGestureHandler#f3f0e relayoutBoundary=up10 NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE flutter: Another exception was thrown: RenderBox was not laid out: RenderPointerListener#79bd7 relayoutBoundary=up9 NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE flutter: Another exception was thrown: RenderBox was not laid out: _RenderScrollSemantics#9c289 relayoutBoundary=up8 NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE flutter: Another exception was thrown: RenderBox was not laid out: RenderViewport#3e402 NEEDS-PAINT Reloaded 0 of 590 libraries in 436ms.

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