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Layout 颤振应用程序中屏幕底部的背景图像_Layout_Dart_Flutter - Fatal编程技术网

Layout 颤振应用程序中屏幕底部的背景图像

Layout 颤振应用程序中屏幕底部的背景图像,layout,dart,flutter,Layout,Dart,Flutter,在我的flatter应用程序中,我试图在屏幕底部放置一个背景图像。我使用了一个堆栈将背景与我的应用程序内容分开,并使用一个带有扩展容器的列将我的图像推到底部 不幸的是,这种组合导致我的应用程序崩溃。如果我从背景中删除该列,效果会很好。因此,有关计算布局的某些内容失败了 进口“包装:颤振/材料.省道”; void main=>runAppnew MyApp; 类MyApp扩展了无状态小部件{ @凌驾 小部件构建上下文上下文{ 返回新材料PP 标题:“颤振演示”, 主题:新主题数据 主样本:颜色。灰

在我的flatter应用程序中,我试图在屏幕底部放置一个背景图像。我使用了一个堆栈将背景与我的应用程序内容分开,并使用一个带有扩展容器的列将我的图像推到底部

不幸的是,这种组合导致我的应用程序崩溃。如果我从背景中删除该列,效果会很好。因此,有关计算布局的某些内容失败了

进口“包装:颤振/材料.省道”; void main=>runAppnew MyApp; 类MyApp扩展了无状态小部件{ @凌驾 小部件构建上下文上下文{ 返回新材料PP 标题:“颤振演示”, 主题:新主题数据 主样本:颜色。灰色, , 家:脚手架 正文:背景, , ; } } 类背景扩展了无状态小部件{ @凌驾 小部件构建上下文上下文{ 返回堆栈 儿童:[ 柱 儿童:[ 扩大 子:容器, , 容器 装饰:盒子装饰 图像:装饰图像 图像:AssetImageassets/background.png, 适合:BoxFit.fitWidth, , , , ], , 居中 孩子:TextApp的内容会在这里, , ], ; } } 堆栈跟踪:

颤振:══╡ 服务捕获的异常╞══════════════════════════════════════════════════════════════════ 颤振:解析图像编解码器时抛出以下断言: 颤振:无法加载资源:assets/background.png 颤振: 颤振:抛出异常时,这是堆栈: 颤振:0平台组装包。加载包:颤振/src/服务/资产包。dart:221:7 颤振: flatter:1 AssetBundleImageProvider.\u加载异步包:flatter/src/painting/image\u provider.dart:427:44 颤振: 颤振:2个AssetBundleImageProvider。加载包:颤振/src/Paint/image_provider。dart:412:14 颤振:3图像提供程序。解决。。包装:颤振/src/painting/image_供应商。dart:266:86 flatter:4 ImageCache.putIfAbsent包:flatter/src/painting/image\u cache.dart:143:20 颤振:5 ImageProvider.resolve。包装:颤振/src/painting/image_供应商。dart:266:63 颤振:6 SynchronousFuture。然后包:颤振/src/foundation/synchronous_future。dart:38:29 flatter:7 ImageProvider.resolve包:flatter/src/painting/image\u provider.dart:264:30 颤振:8装饰图像画家。油漆包:颤振/src/油漆/装饰图像。省道:239:55 flatter:9 _-BoxDecorationPainter._-paintbackground图片包:flatter/src/painting/boxdecoration.dart:395:19 颤振:10箱装饰油漆工。油漆包装:颤振/src/油漆/箱装饰。省道:413:5 flatter:11渲染装饰框。油漆包:flatter/src/rendering/proxy_-box。dart:1876:16 flatter:12 RenderObject.\u paintWithContext包:flatter/src/rendering/object.dart:2024:7 flatter:13 PaintingContext.paintChild包:flatter/src/rendering/object.dart:131:13 颤振:14 _RenderFlex&RenderBox&containerrenderrobjectmixin&RenderBoxContainerDefaultsMixin.defaultPaint包:颤振/src/rendering/box.dart:2222:15 颤振:15 RenderFlex.paint包:颤振/src/rendering/flex.dart:931:7 flatter:16 RenderObject.\u paintWithContext包:flatter/src/rendering/object.dart:2024:7 flatter:17 PaintingContext.paintChild包:flatter/src/rendering/object.dart:131:13 颤振:18_RenderStack&RenderBox&ContainerRenderObjectMixin&RenderBoxContainerDefaultsMixin.defaultPaint包:颤振/src/rendering/box.dart:2222:15 flatter:19 RenderStack.paintStack包:flatter/src/rendering/stack.dart:604:5 flatter:20 RenderStack.paint包:flatter/src/rendering/stack.dart:612:7 flatter:21 RenderObject.\u paintWithContext包:flatter/src/rendering/object.dart:2024:7 flatter:22 PaintingContext.paintChild包:flatter/src/rendering/object.dart:131:13 颤振:23(u renderrcustommulti-childlayoutbox&RenderBox&ContainerRenderObjectMixin&RenderBoxContainerDefaultsMixin.defaultPaint包:颤振/src/rendering/box.dart:2222:15 flatter:24 rendercutommultichildlayoutbox.paint包:flatter/src/rendering/custom_布局。dart:360:5 flatter:25 RenderObject.\u paintWithContext包:flatter/src/rendering/object.dart:2024:7 flatter:26 PaintingContext.paintChild包:flatter/src/rendering/object.dart:131:13 颤振:27 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&renderProxy box Mixin。油漆包:颤振/src/渲染/代理_box。省道:127:15 颤振:28_RenderInkFeatures.油漆包装:颤振/src/材料/材料.省道:456:11 flatter:29 RenderObject.\u paintWithContext包:flatter/src/rendering/object.da rt:2024:7 flatter:30 PaintingContext.paintChild包:flatter/src/rendering/object.dart:131:13 颤振:31 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&renderProxy box Mixin。油漆包:颤振/src/渲染/代理_box。省道:127:15 颤振:32 RenderPhysicalModel.paint包:颤振/src/rendering/proxy_-box.dart:1644:15 flatter:33 RenderObject.\u paintWithContext包:flatter/src/rendering/object.dart:2024:7 flatter:34 PaintingContext.paintChild包:flatter/src/rendering/object.dart:131:13 颤振:35 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&renderProxy box Mixin。油漆包:颤振/src/渲染/代理_box。省道:127:15 flatter:36 RenderObject.\u paintWithContext包:flatter/src/rendering/object.dart:2024:7 flatter:37 PaintingContext.paintChild包:flatter/src/rendering/object.dart:131:13 颤振:38 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&renderProxy box Mixin。油漆包:颤振/src/渲染/代理_box。省道:127:15 flatter:39 RenderObject.\u paintWithContext包:flatter/src/rendering/object.dart:2024:7 flatter:40 PaintingContext.repaincomposited子包:flatter/src/rendering/object.dart:111:11 颤振:41 PipelineOwner.flushPaint包:颤振/src/rendering/object.dart:791:29 颤振:42 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&RenderBinding.drawFrame包:颤振/src/rendering/binding.dart:272:19 颤振:43 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&renderbinding&WidgetsBinding.drawFrame包:颤振/src/widgets/binding.dart:627:13 颤振:44 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&RendererBinding._handlePersistentFrameCallback包:颤振/src/rendering/binding.dart:208:5 颤振:45 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding._invokeFlameCallback包:颤振/src/scheduler/binding.dart:990:15 颤振:46 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding.handleDrawFrame包:颤振/src/scheduler/binding.dart:930:9 颤振:47 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding._handleDrawFrame包:颤振/src/scheduler/binding.dart:842:5 颤振:48 _调用省道:ui/挂钩。省道:120:13 颤振:49_抽框省道:ui/挂钩。省道:109:3 颤振: 颤振:图像提供程序:AssetImagebundle:null,名称:assets/background.png 颤振:图像键:AssetBundleImageKeybundle:PlatformAssetBundle3853b,名称:assets/background.png, 颤振:比例:1.0 颤振:════════════════════════════════════════════════════════════════════════════════════════════════════ 错误-从应用程序收到32000:服务器错误 有什么建议吗?这是颤振不可能的布局请求吗?

您可以直接使用Image.asset和alignment:alignment.bottomCenter组合使用

您可以直接将Image.asset与路线组合使用:alignment.bottomCenter


如果需要更高的精度,也可以像这样手动定位或对齐装饰图像

       Container(
                padding: EdgeInsets.all(18),
                decoration: BoxDecoration(
                image: DecorationImage(
                    image: AssetImage('assets/images/books.png'),
                    alignment: Alignment(-1, -0.5),  
                   // This align it Center Left + a little bit up
                  ),
                 ),
Alignment0.0,0.0表示矩形的中心。从-1.0到+1.0的距离是从矩形的一侧到矩形的另一侧的距离

更多信息请访问官方文档

如果需要更高的精度,也可以像这样手动定位或对齐装饰图像

       Container(
                padding: EdgeInsets.all(18),
                decoration: BoxDecoration(
                image: DecorationImage(
                    image: AssetImage('assets/images/books.png'),
                    alignment: Alignment(-1, -0.5),  
                   // This align it Center Left + a little bit up
                  ),
                 ),
Alignment0.0,0.0表示矩形的中心。从-1.0到+1.0的距离是从矩形的一侧到矩形的另一侧的距离

更多信息请访问官方文档

alignment:alignment.bottomLeft,解决了我的图像上下位置问题。谢谢。alignment:alignment.bottomLeft,解决了我的图像上下位置问题。谢谢