Grails+Ext之form scaffolding

最新推荐文章于 2022-11-02 11:16:20 发布

最新推荐文章于 2022-11-02 11:16:20 发布 · 583 阅读

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本文介绍了一种基于Grails的scaffolding理念为ExtJS自动生成表单的方法。通过从领域模型中提取字段信息，并根据约束顺序排列，实现表单的自动化构建。此方法不仅简化了开发流程，还确保了表单与模型的一致性。

以上图片中间部分是个自动生成的form，不用专门给它写代码或用“表单设计器”工具手工生成代码。这种方法绝非rocket science，只是scaffolding雕虫小技而已。

Grails的scaffolding生成的是HTML代码，而不是JSON形式的form定义，无法直接跟Ext无缝整合。

为Ext写个form scaffolding并非难事。跟Grails的scaffolding原理一致，表单中的fields是从domain class中提取出来的，排序则按照它们在constraints中出现的先后顺序。

先看一个domain class的示例：

class SiteContactLog {
    
    @Hidden // Gotta hide it, otherwise it will be rendered as a combobox by default. And loading all sites is time-consuming
    Site site

    @Hidden
    User user
    
    Date contactDate
    
    @Xtype(xtype='timefield')
    String contactTime
    
    @SelectionItemFetcher(fetcher="{d->app.getArtefact('Domain','com.xxx.sctms.Person').clazz.findAll('site.id':d._belongsTo)}")
    @LiveSearch(searchBy='name')
    List<Person> personsContacted
    
    @SelectionItemFilter(filter="{d,q->q.descend('group').constrain('siteContactCorrespondence');q.descend('name').orderAscending()}")
    GenericSelectionItem correspondence
    
    @SelectionItemFilter(filter="{d,q->q.descend('group').constrain('siteContactDirection');q.descend('name').orderAscending()}")
    GenericSelectionItem direction
     
    @SelectionItemFilter(filter="{d,q->q.descend('group').constrain('siteContactMethod');q.descend('name').orderAscending()}")
    GenericSelectionItem contactMethod
    
    @SelectionItemFilter(filter="{d,q->q.descend('group').constrain('siteContactTopic');q.descend('seq').orderAscending()}")
    GenericSelectionItem topic

    String summary

    static constraints = {
        contactDate nullable:false
        contactTime()
        personsContacted nullable:false, minSize:1
        correspondence nullable:false
        direction()
        contactMethod()
        topic()
        summary nullable:false, blank:false, maxSize:Integer.MAX_VALUE
    }

}

基于domain生成form的机理用以下两个代码片段说明：

static retrieveDomainFields(domain) {
      def artefact = getDomainArtefact(domain)
      def fields = []
      def constrainedProperties = artefact.constrainedProperties
      artefact.properties.each{
        if(!("${it.name}" ==~ /id|parentId|version|dateCreated|createdBy|deleted|dateDeleted|deletedBy/)) {
          def ext = [:]
          def declaredField = artefact.clazz.getDeclaredField(it.name)

          def label = declaredField.getAnnotation(com.xxx.annotations.Label.class)
          def formattedName = label?.label() ?: getFormattedNameByConvention(it.name)

          // extra configurations from annotations:
          def embeddedObject = declaredField.getAnnotation(com.xxx.annotations.EmbeddedObject.class)
          if(embeddedObject) {
            ext['embeddedObject'] = [height: embeddedObject.height(), width: embeddedObject.width()]
          }
          def singleCheckBox = declaredField.getAnnotation(com.xxx.annotations.SingleCheckBox.class)
          if(singleCheckBox) {
            ext['singleCheckBox'] = true
          }
          def radio = declaredField.getAnnotation(com.xxx.annotations.Radio.class)
          if(radio) {
            ext['radio'] = true
          }
          def liveSearch = declaredField.getAnnotation(com.xxx.annotations.LiveSearch.class)
          if(liveSearch) {
            ext['liveSearch'] = true
          }
          def hidden = declaredField.getAnnotation(com.xxx.annotations.Hidden.class)
          if(hidden) {
            ext['hidden'] = true
          }
          def xtype = declaredField.getAnnotation(com.xxx.annotations.Xtype.class)
          if(xtype) {
            ext['xtype'] = xtype.xtype()
          }// TODO: inject more extensions from other annotations...

          ext['declaredField'] = declaredField

          if(constrainedProperties."${it.name}") {
              if(constrainedProperties."${it.name}".maxSize) {
                  ext['maxSize'] = constrainedProperties."${it.name}".maxSize
              }
          }

//          fields << [it.name, formattedName, formattedName, it.type, ext] // name, formattedName, description, type, ext
          fields << [it.name, formattedName, formattedName, ext] // name, formattedName, description, ext (declaredField has been added to ext, do we still need it.type?)
        }
      }

      // sort by the sequence they appear in the constraints
      fields.sort{f1,f2->
         def cp1 = constrainedProperties[f1[0]]
         def cp2 = constrainedProperties[f2[0]]
         cp1?(cp2?cp1.order<=>cp2.order:1):(cp2?-1:0)
      }

      fields
  }

private buildFormScaffold(domain, fields) {
        def artefact = DomainUtils.getDomainArtefact(domain)
        def dn = artefact.clazz.name

        def maxCaptionWidthAndControlsTotalHeight = processFields(fields)
        def captionWidth = maxCaptionWidthAndControlsTotalHeight[0], captionHeight = 22, controlsTotalHeight = maxCaptionWidthAndControlsTotalHeight[1]

        def width = COMPONENT_WIDTH, top = FORM_MARGIN, left = captionWidth + FORM_MARGIN, tabIndex = 100
        def processingRightHalf = false, leftTop = 0, rightTop = 0

        def leftControlsTotalHeight = 0

        def scaffold = [
            "id":"${UUID.randomUUID()}",
            "xtype":"form",
            "layout":"absolute",
            "name":dn,
            "height":0, //TBD
            "width":(captionWidth + width + FORM_MARGIN*2)*2,
            "title":"FORM SCAFFOLD",
            "items":[]]

        for(int i = 0; i < fields.size(); i++) {
            if(leftControlsTotalHeight*2 >= controlsTotalHeight && !processingRightHalf) {
                // reset top and left
                processingRightHalf = true
                top = FORM_MARGIN
                left += (width + FORM_MARGIN * 2 + captionWidth)
            }

            def field = fields[i]

            // e.g., Site has a 'study' field, and site belongs to study
            // the study field should not show up
            if(isBelongsToField(dn, field[0]) || field[3]['hidden'])continue

            def htmlType = field[3].xtype ?: field[3].htmlType

            def nullableConstraint = artefact.constraints."${field[0]}".getAppliedConstraint('nullable')
            scaffold.items << [
              xtype:htmlType,id:"${UUID.randomUUID()}",name:field[0],
		      allowBlank:nullableConstraint ? nullableConstraint.isNullable() : true,
              forceSelection:false,
              readOnly:false,
              captionText:field[1],captionPosition:"Left",captionHeight:captionHeight,captionWidth:captionWidth,
              x:(left-(htmlType=='placeHolder'?captionWidth:0)),y:top,
              height:field[3].height,width:(width+(htmlType=='placeHolder'?captionWidth:0)),tabIndex:tabIndex]
            if(htmlType == 'datefield') {
                scaffold.items[-1].format = DATE_FORMAT    
            } else if(htmlType == 'radiogroup') {
                if(field[3].singleCheckBox) {
                    scaffold.items[-1].xtype = 'checkbox'
                    scaffold.items[-1].singleCheckBox = true
                    scaffold.items[-1].xtype = "checkbox"
                    scaffold.items[-1].boxLabel = field[1]
                    scaffold.items[-1].y += 4
                }
            }

            tabIndex += 100
            top      += (field[3].height + 4)

            if(processingRightHalf) {
                rightTop = top
            } else {
                leftControlsTotalHeight += field[3].height
                leftTop  = top
            }
        }
        scaffold.height = (leftTop > rightTop ? leftTop : rightTop) + (FORM_MARGIN-4)
        scaffold as JSON
    }

生成的form形如

{
   "id" : "a4fe0cda-ec31-4ec0-a809-bdbe73891fdf", "xtype" : "form", "layout" : "absolute", "name" : "com.xxx.sctms.SiteContactLog", "height" : 236, "width" : 832, "title" : "FORM SCAFFOLD", "items" : [ {
      "xtype" : "datefield", "id" : "f9a7a0ab-6799-473c-b811-7a6957ea95cc", "name" : "contactDate", "allowBlank" : false, "forceSelection" : false, "readOnly" : false, "captionText" : "Contact Date", "captionPosition" : "Left", "captionHeight" : 22, "captionWidth" : 136, "x" : 151, "y" : 15, "height" : 22, "width" : 250, "tabIndex" : 100, "format" : "M/d/Y"}
   , {
      "xtype" : "timefield", "id" : "838ec058-4ccb-4134-81df-c77d001365da", "name" : "contactTime", "allowBlank" : true, "forceSelection" : false, "readOnly" : false, "captionText" : "Contact Time", "captionPosition" : "Left", "captionHeight" : 22, "captionWidth" : 136, "x" : 151, "y" : 41, "height" : 22, "width" : 250, "tabIndex" : 200}
   , {
      "xtype" : "checkboxgroup", "id" : "7ad425bc-49e4-4c93-9051-a42c7a42d197", "name" : "personsContacted", "allowBlank" : false, "forceSelection" : false, "readOnly" : false, "captionText" : "Persons Contacted", "captionPosition" : "Left", "captionHeight" : 22, "captionWidth" : 136, "x" : 151, "y" : 67, "height" : 102, "width" : 250, "tabIndex" : 300}
   , {
      "xtype" : "combo", "id" : "34e2a5fd-c37d-41b5-ad26-4c98ec5a91f6", "name" : "correspondence", "allowBlank" : false, "forceSelection" : false, "readOnly" : false, "captionText" : "Correspondence", "captionPosition" : "Left", "captionHeight" : 22, "captionWidth" : 136, "x" : 151, "y" : 173, "height" : 22, "width" : 250, "tabIndex" : 400}
   , {
      "xtype" : "combo", "id" : "c146e14d-2ac7-4cbd-8648-55c3f62bb306", "name" : "direction", "allowBlank" : true, "forceSelection" : false, "readOnly" : false, "captionText" : "Direction", "captionPosition" : "Left", "captionHeight" : 22, "captionWidth" : 136, "x" : 151, "y" : 199, "height" : 22, "width" : 250, "tabIndex" : 500}
   , {
      "xtype" : "combo", "id" : "93070ee3-1def-4c93-b7c1-2a722ed20409", "name" : "contactMethod", "allowBlank" : true, "forceSelection" : false, "readOnly" : false, "captionText" : "Contact Method", "captionPosition" : "Left", "captionHeight" : 22, "captionWidth" : 136, "x" : 567, "y" : 15, "height" : 22, "width" : 250, "tabIndex" : 600}
   , {
      "xtype" : "combo", "id" : "a3a427dd-c499-4378-9e63-f9a3d59e2958", "name" : "topic", "allowBlank" : true, "forceSelection" : false, "readOnly" : false, "captionText" : "Topic", "captionPosition" : "Left", "captionHeight" : 22, "captionWidth" : 136, "x" : 567, "y" : 41, "height" : 22, "width" : 250, "tabIndex" : 700}
   , {
      "xtype" : "textarea", "id" : "ef85d8cb-50e6-4508-9d9c-83056208427e", "name" : "summary", "allowBlank" : false, "forceSelection" : false, "readOnly" : false, "captionText" : "Summary", "captionPosition" : "Left", "captionHeight" : 22, "captionWidth" : 136, "x" : 567, "y" : 67, "height" : 102, "width" : 250, "tabIndex" : 800}
   ]}

这样生成的form排版比较单一，分两栏，高度大致相等。若需修改，可使用表单设计器...