The 瓦丁框架指南有一个描述如何使用列渲染器的页面 in a 瓦丁网格. And 本页描述了渲染器的实现，但一切都太短暂了。
我想实施一个InstantRenderer补充 Vaadin 8.1 中添加的部分 java.time 渲染器集。添加了渲染器LocalDate & LocalDateTime但不是为了Instant, OffsetDateTime, and ZonedDateTime。为了我的Instant渲染器我目前只是应用当前的默认时区（ZoneId）得到一个ZonedDateTime我称之为toString方法。还可以做更多的事情，但这只是开始。
所以我的代码应该与提供的非常相似LocalDateTimeRenderer。我正在尝试遵循该代码作为指导。
在搜索 Vaadin 源代码并阅读文档时，我似乎需要三段源代码：
InstantRenderer（ 如同LocalDateTimeRenderer ) InstantRendererConnector（ 如同LocalDateTimeRendererConnector )InstantRendererState（ 如同LocalDateTimeRendererState )我已经做到了这一点，并且一切都编译通过。但我的表格无法渲染，我得到的只是页面上的一个白色空框。控制台或日志上没有出现错误。如果我删除对我的使用InstantRenderer，然后回退到让我的Instant对象默认渲染它们自己的toString方法，一切顺利，表格按预期显示。所以我知道我的自定义渲染器有问题。
当谈到“服务器端”与“客户端”Vaadin 时，我是一个新手。
➠ 我需要执行某种包装吗？目前，我在 Vaadin 项目中开设了三门课程MyUI源文件。
➠ 我还漏掉了其他部分吗？
我通过调用无参数构造函数来实例化渲染器：
this.entriesGrid
.addColumn( Entry::getStart )
.setCaption( "Start" )
.setRenderer( new InstantRenderer( ) )
;
这是我上面列出的三个文件，几乎完全取自 Vaadin 源代码。
InstantRenderer/*
* By Basil Bourque. Taken almost entirely from source code published by Vaadin Ltd.
*
* --------
*
* Copyright 2000-2016 Vaadin Ltd.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.basil.timepiece;
import java.time.Instant;
import java.time.ZoneId;
import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
import java.time.format.FormatStyle;
import java.util.Locale;
import elemental.json.JsonValue;
/**
* A renderer for presenting {@code Instant} objects.
*
* @author Vaadin Ltd
* @since 8.1
*/
public class InstantRenderer
extends com.vaadin.ui.renderers.AbstractRenderer< Object, Instant >
{
private DateTimeFormatter formatter;
private boolean getLocaleFromGrid;
private ZoneId zoneId = ZoneId.systemDefault(); // Basil Bourque.
/**
* Creates a new InstantRenderer.
* <p>
* The renderer is configured to render with the grid's locale it is
* attached to, with the format style being {@code FormatStyle.LONG} for the
* date and {@code FormatStyle.SHORT} for time, with an empty string as its
* null representation.
*
* @see <a href=
* "https://docs.oracle.com/javase/8/docs/api/java/time/format/FormatStyle.html#LONG">
* FormatStyle.LONG</a>
* @see <a href=
* "https://docs.oracle.com/javase/8/docs/api/java/time/format/FormatStyle.html#SHORT">
* FormatStyle.SHORT</a>
*/
public InstantRenderer ()
{
this( DateTimeFormatter.ofLocalizedDateTime( FormatStyle.LONG , FormatStyle.SHORT ) , "" );
getLocaleFromGrid = true;
}
/**
* Creates a new InstantRenderer.
* <p>
* The renderer is configured to render with the given formatter, with the
* empty string as its null representation.
*
* @param formatter the formatter to use, not {@code null}
* @throws IllegalArgumentException if formatter is null
*/
public InstantRenderer ( DateTimeFormatter formatter )
{
this( formatter , "" );
}
/**
* Creates a new InstantRenderer.
* <p>
* The renderer is configured to render with the given formatter.
*
* @param formatter the formatter to use, not {@code null}
* @param nullRepresentation the textual representation of the {@code null} value
* @throws IllegalArgumentException if formatter is null
*/
public InstantRenderer ( DateTimeFormatter formatter , String nullRepresentation )
{
super( Instant.class , nullRepresentation );
if ( formatter == null )
{
throw new IllegalArgumentException( "formatter may not be null" );
}
this.formatter = formatter;
}
/**
* Creates a new InstantRenderer.
* <p>
* The renderer is configured to render with the given string format, as
* displayed in the grid's locale it is attached to, with an empty string as
* its null representation.
*
* @param formatPattern the format pattern to format the date with, not {@code null}
* @throws IllegalArgumentException if format pattern is null
* @see <a href=
* "https://docs.oracle.com/javase/8/docs/api/java/time/format/DateTimeFormatter.html#patterns">
* Format Pattern Syntax</a>
*/
public InstantRenderer ( String formatPattern )
{
this( formatPattern , Locale.getDefault() );
getLocaleFromGrid = true;
}
/**
* Creates a new InstantRenderer.
* <p>
* The renderer is configured to render with the given string format, as
* displayed in the given locale, with an empty string as its null
* representation.
*
* @param formatPattern the format pattern to format the date with, not {@code null}
* @param locale the locale to use, not {@code null}
* @throws IllegalArgumentException if format pattern is null
* @throws IllegalArgumentException if locale is null
* @see <a href=
* "https://docs.oracle.com/javase/8/docs/api/java/time/format/DateTimeFormatter.html#patterns">
* Format Pattern Syntax</a>
*/
public InstantRenderer ( String formatPattern , Locale locale )
{
this( formatPattern , locale , "" );
}
/**
* Creates a new InstantRenderer.
* <p>
* The renderer is configured to render with the given string format, as
* displayed in the given locale.
*
* @param formatPattern the format pattern to format the date with, not {@code null}
* @param locale the locale to use, not {@code null}
* @param nullRepresentation the textual representation of the {@code null} value
* @throws IllegalArgumentException if format pattern is null
* @throws IllegalArgumentException if locale is null
* @see <a href=
* "https://docs.oracle.com/javase/8/docs/api/java/time/format/DateTimeFormatter.html#patterns">
* Format Pattern Syntax</a>
*/
public InstantRenderer ( String formatPattern , Locale locale , String nullRepresentation )
{
super( Instant.class , nullRepresentation );
if ( formatPattern == null )
{
throw new IllegalArgumentException( "format pattern may not be null" );
}
if ( locale == null )
{
throw new IllegalArgumentException( "locale may not be null" );
}
formatter = DateTimeFormatter.ofPattern( formatPattern , locale );
}
@Override
public JsonValue encode ( Instant value )
{
String dateString;
if ( value == null )
{
dateString = this.getNullRepresentation();
} else if ( this.getLocaleFromGrid )
{
if ( null == this.getParentGrid() )
{
throw new IllegalStateException(
"Could not find a locale to format with: "
+ "this renderer should either be attached to a grid "
+ "or constructed with locale information" );
}
ZonedDateTime zdt = value.atZone( this.zoneId ); // Basil Bourque.
Locale locale = this.getParentGrid().getLocale();
dateString = zdt.format( formatter.withLocale( locale ) );
} else
{
ZonedDateTime zdt = value.atZone( this.zoneId ); // Basil Bourque.
dateString = zdt.format( formatter );
}
return encode( dateString , String.class );
}
@Override
protected InstantRendererState getState ()
{
InstantRendererState s = ( InstantRendererState ) super.getState();
return s;
}
@Override
protected InstantRendererState getState ( boolean markAsDirty )
{
InstantRendererState s = ( InstantRendererState ) super.getState( markAsDirty );
return s;
}
}
InstantRendererConnector/*
* By Basil Bourque. Taken almost entirely from source code published by Vaadin Ltd.
*
* --------
*
* Copyright 2000-2016 Vaadin Ltd.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.basil.timepiece;
import com.vaadin.shared.ui.Connect;
/**
* A connector for InstantRenderer.
* <p>
* The server-side Renderer operates on {@code Instant}s, but the data is
* serialized as a string, and displayed as-is on the client side. This is to be
* able to support the server's locale.
*
* @author Vaadin Ltd
* @since 8.1
*/
@Connect( InstantRenderer.class )
public class InstantRendererConnector extends com.vaadin.client.connectors.grid.TextRendererConnector
{
@Override
public InstantRendererState getState ()
{
return ( InstantRendererState ) super.getState();
}
}
InstantRendererState/*
* By Basil Bourque. Taken almost entirely from source code published by Vaadin Ltd.
*
* --------
*
* Copyright 2000-2016 Vaadin Ltd.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.basil.timepiece;
/**
* Shared state of InstantRenderer.
*
* @author Vaadin Ltd
* @since 8.1
*/
public class InstantRendererState extends com.vaadin.shared.ui.grid.renderers.TextRendererState
{
// This code intentionally left blank.
}
我已经发布了我的BitBucket 上完整的 Maven 驱动项目，列渲染器的所有必需文件Instant, OffsetDateTime, and ZonedDateTime.
我已经发布问题#10208为 Vaadin Grid 的其他 java.time 类型（Instant、OffsetDateTime、ZonedDateTime）实现列渲染器，以补充 Vaadin 8.1 中的 LocalDate 和 LocalDateTime 渲染器。在 Vaadin 框架 GitHub 页面上。
是的，需要特殊包装。你不能简单地扔掉Vaadin 网格列渲染器实现课程进入常规 Vaadin 应用程序。
列渲染器实现所需的三个类中的两个涉及客户端开发，而不是通常的服务器端开发我们通常在 Vaadin 应用程序中进行工作。
幸运的是，这比听起来更容易。为了做一个简单的列渲染器，Vaadin 幸运地提供了一些超类来完成大部分繁重的工作。所以我们不需要了解所有血淋淋的细节GWT and JavaScript瓦丁的幕后魔法正在发生。
成功之路包括：
vaadin-archetype-widget使用开始一个新项目多模块 Maven 原型Vaadin 团队提供：vaadin-archetype-widget见于这个清单.
addon module一旦您根据该原型创建了一个项目IDE，添加您的三列渲染器类，如本屏幕截图所示Instant渲染器。
Renderer类位于“addon”模块的主包中。RendererConnector & RendererState类文件位于“addon”模块的嵌套中client包裹。当然，在实际工作中你会删除这个例子MyComponent…由原型创建的文件。
demo module构建完成后，您可以通过导入“addon”模块的包在“demo”模块的 Vaadin 应用程序中尝试列渲染器。在这种情况下：
import org.basilbourque.timecolrenderers.InstantRenderer;
我成功实施了Instant列渲染器完全取自三个LocalDateTimeRendererVaadin 8.1.3 源代码中提供了相关类。您可以通过键入找到这些类的当前版本LocalDateTimeRenderer in the GitHub 查找文件功能.
