带有VAADIN 8，Gradle和SpringBoot的画布插件

Question

I am new to all Gradle, VAADIN and Spring, and am just working through a simple VAADIN Spring Boot tutorial ( https://spring.io/guides/gs/crud-with-vaadin/ ) and tried to add the Canvas add-on from https://github.com/hezamu/vaadincanvas , but when I add the compile dependency

compile("org.vaadin.hezamu:canvas:2.3.0")

a VAADIN widget compile will fail with tons of weird errors:

Using Gradle Vaadin Plugin 1.3.1
:vaadinPluginVersionCheck SKIPPED
:compileJava UP-TO-DATE
:vaadinUpdateWidgetset
:processResources UP-TO-DATE
:classes UP-TO-DATE
:vaadinClassPathJar UP-TO-DATE
Errors in 'jar:file:/C:/Users/msc/.gradle/caches/modules-2/files-2.1/com.vaadin/vaadin-client/8.1.8/93548adad170aea9fe62ab742908fe63fe0ec321/vaadin-client-8.1.8.jar!/com/vaadin/client/extensions/DragSourceExtensionConnector.java'
Line 413: The method getState() from the type DragSourceExtensionConnector refers to the missing type DragSourceState
Line 38: The import com.vaadin.shared.ui.dnd cannot be resolved
Line 433: DragSourceRpc cannot be resolved to a type
Line 605: DragSourceState cannot be resolved to a type
Line 39: The import com.vaadin.shared.ui.dnd cannot be resolved
Line 507: DragSourceRpc cannot be resolved to a type
Line 190: The method getState() from the type DragSourceExtensionConnector refers to the missing type DragSourceState
Line 433: The method getRpcProxy(Class<T>) in the type AbstractConnector is not applicable for the arguments (Class<DragSourceRpc>)
Line 212: DragSourceState cannot be resolved to a variable
Line 492: DropEffect cannot be resolved
Line 606: DragSourceState cannot be resolved to a type

Just by removing that one dependency, the project builds. This is the entire Gradle build file:

buildscript {
    repositories {
        jcenter()
        mavenCentral()
    }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:1.5.10.RELEASE")
        classpath "com.devsoap.plugin:gradle-vaadin-plugin:1.3.1"
        classpath "javax.validation:validation-api:1.1.0.Final"
    }
}

plugins {
    id "com.devsoap.plugin.vaadin" version "1.3.1"
}

apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'idea'
apply plugin: 'org.springframework.boot'
apply plugin: 'com.devsoap.plugin.vaadin'

jar {
    baseName = 'gs-crud-with-vaadin'
    version =  '0.1.0'
}

repositories {
    mavenCentral()
    maven { url "https://oss.sonatype.org/content/repositories/vaadin-snapshots" }
    maven { url "https://repository.jboss.org/nexus/content/repositories/releases" }
    maven { url "http://oss.sonatype.org/content/repositories/vaadin-snapshots/" }
    maven { url "http://vaadin.com/nexus/content/repositories/vaadin-addons/" }
    maven { url "https://plugins.gradle.org/m2/" }
}

sourceCompatibility = 1.8
targetCompatibility = 1.8

dependencyManagement {
  imports {
    mavenBom 'com.vaadin:vaadin-bom:8.0.0'
  }
}

dependencies {
    compile("org.springframework.boot:spring-boot-starter-data-jpa")
    compile("com.vaadin:vaadin-spring-boot-starter")
    compile("org.springframework.boot:spring-boot-starter-actuator")
    compile("org.vaadin.hezamu:canvas:2.3.0")
    compile("com.h2database:h2")
    testCompile("junit:junit")
    testCompile("org.springframework.boot:spring-boot-starter-test")
}

What am I doing wrong? I am using Gradle 4.1 and Java 8.

Answer 1

There is a problem with your vaadin version. You have a bom with 8.0.0 but I guess the gradle plugin tries to use a newer version (8.1.8).

With Vaadin 8.1 the drag&drop Handling changed. I guess the addon doesn't support Vaadin 8.1 because it was released before.

You have three options.

1. Use some other addon if possible.
2. Fix the addon yourself

3. Or as a last resort add the following code to your build gradle to stay at Vaadin 8.0

   vaadin { version '8.0.7' }

Answer 2

Well, I got it to work after "fine-tuning" all versions. VAADIN, its' addons and Gradle seem to be a fickle team. It works with the spring-boot gradle plugin 1.4.7.RELEASE (important!), VAADIN 8.1.1, the devsoap VAADIN Gradle plugin 1.3.1, the multifileupload addon 3.0.1 and the canvas addon 2.2.0.

Pretty much any change in any of these versions, and something falls apart.