具有核心数据关系的NSPredicateEditor

Question

我有一个包含两个实体的核心数据模型，Document和Field:

• 文件：

  • 字段[对多关系]

• 字段：

  • 名称
  • fieldText
  • fieldDate
  • fieldNumber
  • 文件[到一个关系]

我正在尝试设置一个NSPredicateEditor，允许某人根据某些字段的内容筛选文档。我手动构建谓词编辑器，如下所示：

func updatePredicateEditor() {
    print("updatePredicateEditor")
    let sortDescriptor = NSSortDescriptor(key: "orderIndex", ascending: true)
    fieldsArrayController.sortDescriptors = [sortDescriptor]
    let fields = fieldsArrayController.arrangedObjects as! [Field]
    var keyPathsStringArray = [NSExpression]()
    var stringFieldNames = [String]()
    var keyPathsDateArray = [NSExpression]()
    var dateFieldNames = [String]()
    var keyPathsNumberArray = [NSExpression]()
    var numberFieldNames = [String]()
    for i in 0..<fields.count {
        let currentField = fields[i] 
        switch currentField.type! {
        case "Text":
            keyPathsStringArray.append(NSExpression(forKeyPath: "fieldText"))
            stringFieldNames.append(currentField.name!)
        case "Date":
            keyPathsDateArray.append(NSExpression(forKeyPath: "fieldDate"))
            dateFieldNames.append(currentField.name!)
        case "Number":
            keyPathsNumberArray.append(NSExpression(forKeyPath: "fieldNumber"))
            numberFieldNames.append(currentField.name!)
        default:
            print("error on field type")
        }
    }
    let stringOperators = [NSNumber(unsignedInteger: NSPredicateOperatorType.ContainsPredicateOperatorType.rawValue),
                           NSNumber(unsignedInteger: NSPredicateOperatorType.EqualToPredicateOperatorType.rawValue),
                           NSNumber(unsignedInteger: NSPredicateOperatorType.NotEqualToPredicateOperatorType.rawValue),
                           NSNumber(unsignedInteger: NSPredicateOperatorType.BeginsWithPredicateOperatorType.rawValue),
                           NSNumber(unsignedInteger: NSPredicateOperatorType.EndsWithPredicateOperatorType.rawValue)]
    let numberOperators = [NSNumber(unsignedInteger: NSPredicateOperatorType.EqualToPredicateOperatorType.rawValue),
                           NSNumber(unsignedInteger: NSPredicateOperatorType.NotEqualToPredicateOperatorType.rawValue),
                           NSNumber(unsignedInteger: NSPredicateOperatorType.LessThanPredicateOperatorType.rawValue),
                           NSNumber(unsignedInteger: NSPredicateOperatorType.LessThanOrEqualToPredicateOperatorType.rawValue),
                           NSNumber(unsignedInteger: NSPredicateOperatorType.GreaterThanPredicateOperatorType.rawValue),
                           NSNumber(unsignedInteger: NSPredicateOperatorType.GreaterThanOrEqualToPredicateOperatorType.rawValue)]

    let dateOperators = [NSNumber(unsignedInteger: NSPredicateOperatorType.EqualToPredicateOperatorType.rawValue),
                         NSNumber(unsignedInteger: NSPredicateOperatorType.NotEqualToPredicateOperatorType.rawValue),
                         NSNumber(unsignedInteger: NSPredicateOperatorType.LessThanPredicateOperatorType.rawValue),
                         NSNumber(unsignedInteger: NSPredicateOperatorType.LessThanOrEqualToPredicateOperatorType.rawValue),
                         NSNumber(unsignedInteger: NSPredicateOperatorType.GreaterThanPredicateOperatorType.rawValue),
                         NSNumber(unsignedInteger: NSPredicateOperatorType.GreaterThanOrEqualToPredicateOperatorType.rawValue)]
    var rowTemplatesTemp = [NSPredicateEditorRowTemplate]() // this is a temp array to hold the different popupbuttons
    // add a template for Strings
    let leftExpressionStringButton : NSPopUpButton
    if keyPathsStringArray.count == 0 {
        print("There aren't any text fields in NSPredicateEditor")
    }
    else {
        let stringTemplate = NSPredicateEditorRowTemplate(leftExpressions: keyPathsStringArray,
                                                                                         rightExpressionAttributeType: NSAttributeType.StringAttributeType,
                                                                                         modifier: NSComparisonPredicateModifier.DirectPredicateModifier,
                                                                                         operators: stringOperators,
                                                                                         options: (Int(NSComparisonPredicateOptions.CaseInsensitivePredicateOption.rawValue) |
                                                                                            Int(NSComparisonPredicateOptions.DiacriticInsensitivePredicateOption.rawValue)))
        leftExpressionStringButton = stringTemplate.templateViews[0] as! NSPopUpButton
        let stringButtonArray = leftExpressionStringButton.itemTitles
        for i in 0..<stringButtonArray.count {
            (leftExpressionStringButton.itemAtIndex(i)! as NSMenuItem).title = stringFieldNames[i] // set button menu names
        }
        rowTemplatesTemp.append(stringTemplate)
    }
    // add another template for Numbers...
    let leftExpressionNumberButton : NSPopUpButton
    if keyPathsNumberArray.count == 0 {
        print("There aren't any number fields in NSPredicateEditor")
    }
    else {
        let numberTemplate = NSPredicateEditorRowTemplate(leftExpressions: keyPathsNumberArray,
                                                                                         rightExpressionAttributeType: NSAttributeType.Integer32AttributeType,
                                                                                         modifier: NSComparisonPredicateModifier.DirectPredicateModifier,
                                                                                         operators: numberOperators,
                                                                                         options: 0)
        leftExpressionNumberButton = numberTemplate.templateViews[0] as! NSPopUpButton
        let numberButtonArray = leftExpressionNumberButton.itemTitles
        for i in 0..<numberButtonArray.count {
            (leftExpressionNumberButton.itemAtIndex(i)! as NSMenuItem).title = numberFieldNames[i] // set button menu names
        }
        rowTemplatesTemp.append(numberTemplate)
    }
    // add another template for Dates...
    let leftExpressionDateButton : NSPopUpButton
    if keyPathsDateArray.count == 0 {
        print("There aren't any date fields in NSPredicateEditor")
    }
    else {
        let dateTemplate = NSPredicateEditorRowTemplate(leftExpressions: keyPathsDateArray,
                                                        rightExpressionAttributeType: NSAttributeType.DateAttributeType,
                                                        modifier: NSComparisonPredicateModifier.DirectPredicateModifier,
                                                        operators: dateOperators,
                                                        options: 0)

        leftExpressionDateButton = dateTemplate.templateViews[0] as! NSPopUpButton
        let dateButtonArray = leftExpressionDateButton.itemTitles
        for i in 0..<dateButtonArray.count {
            (leftExpressionDateButton.itemAtIndex(i)! as NSMenuItem).title = dateFieldNames[i] // set button menu names
        }
        rowTemplatesTemp.append(dateTemplate)
    }
    // create the any, all or none thing...
    let compoundTypes = [NSNumber.init(unsignedInteger: NSCompoundPredicateType.OrPredicateType.rawValue),
                         NSNumber.init(unsignedInteger: NSCompoundPredicateType.AndPredicateType.rawValue),
                         NSNumber.init(unsignedInteger: NSCompoundPredicateType.NotPredicateType.rawValue)]
    // add the compoundtypes
    let compoundTemplate = NSPredicateEditorRowTemplate(compoundTypes: compoundTypes)
    rowTemplatesTemp.append(compoundTemplate)
    print("setting row templates (rowTemplatesTemp)")
    predicateEditor.rowTemplates = rowTemplatesTemp
    predicateEditor.addRow(self)
}

问题是NSPredicateEditor不允许使用NSSubqueryExpressionType的NSEexpressions，所以我不能将子查询作为左表达式。我需要NSPredicateEditorRowTemplate同时包含字段名和属性路径（fieldText、fieldDate或fieldNumber），这样一行中的最终谓词看起来像：

name == FIELDNAME && fieldText CONTAINS "<entered text>"

有什么建议吗？我应该对NSPredicateEditorRowTemplate进行子类化吗？如果是，如何进行？提前感谢您的帮助。

Answer 1

子类NSPredicateEditorRowTemplate并重写predicateWithSubpredicates以将谓词"FIELDNAME CONTAINS <entered text>"转换为谓词"name == FIELDNAME && fieldText CONTAINS <entered text>"。