我正在构建一个带有核心数据的应用程序(1个具有5个属性的实体),它们显示在tableView中.现在我想将这些数据导出到CSV文件(所以我可以通过电话发送此文件),这样我就可以在
windows上的excel中打开它.我搜索了很多,但没有找到正确的答案.有人可以帮助我或给我一个良好的解释或教程的链接？
我正在快速地建造.
func createExportString() -> String {
var merk: String?
var ref: String?
var beschrijving: String?
var aantal: String?
var wbs: String?
var export = NSLocalizedString("merk,ref,beschrijving,aantal,wbs \n",comment: "")
merk = Lijst.valueForKey("merk") as? String
ref = Lijst.valueForKey("ref") as? String
aantal = Lijst.valueForKey("aantal") as? String
beschrijving = Lijst.valueForKey("beschrijving") as? String
wbs = Lijst.valueForKey("wbs") as? String
let merkString = "\(merk!)" ?? "-"
let refString = "\(ref!)" ?? "-"
let beschString = "\(beschrijving!)" ?? "-"
let aantalString = "\(aantal!)" ?? "-"
let wbsString = "\(wbs!)" ?? "-"
export += merkString + "," + refString + "," + beschString + "," + aantalString +
"," + wbsString + "\n"
print("This is what the app will export: \(export)")
return export
}
@IBAction func saveToCSV(sender: AnyObject) {
exportDatabase()
}
func exportDatabase() {
var exportString = createExportString()
saveAndExport(exportString)
}
func saveAndExport(exportString: String) {
let exportFilePath = NSTemporaryDirectory() + "export.csv"
let exportFileURL = NSURL(fileURLWithPath: exportFilePath)
NSFileManager.defaultManager().createFileAtPath(exportFilePath,contents: NSData(),attributes: nil)
var fileHandleError: NSError? = nil
var fileHandle: NSFileHandle? = nil
do {
fileHandle = try NSFileHandle(forWritingToURL: exportFileURL)
} catch {
print( "Error with fileHandle")
}
if fileHandle != nil {
fileHandle!.seekToEndOfFile()
let csvData = exportString.dataUsingEncoding(NSUTF8StringEncoding,allowLossyConversion: false)
fileHandle!.writeData(csvData!)
fileHandle!.closeFile()
let firstActivityItem = NSURL(fileURLWithPath: exportFilePath)
let activityViewController: UIActivityViewController = UIActivityViewController(activityItems: [firstActivityItem],applicationActivities: nil)
self.presentViewController(activityViewController,animated: true,completion: nil)
}
}
解决方法
这是一种简洁的方法,可以完成所有操作 – 传递托管对象数组和CSV文件名字符串.该方法将CSV写入文件.我相信你的代码已经有了大部分内容,缺少的是最后两行,只是将字符串写入“Documents”目录中的新文件.
func writeCoreDataObjectToCSV(objects: [NSManagedObject],named: String) -> String {
/* We assume that all objects are of the same type */
guard objects.count > 0 else {
return
}
let firstObject = objects[0]
let attribs = Array(firstObject.entity.attributesByName.keys)
let csvHeaderString = (attribs.reduce("",combine: {($0 as String) + "," + $1 }) as NSString).substringFromIndex(1) + "\n"
let csvArray = objects.map({object in
(attribs.map({(object.valueForKey($0) ?? "NIL").description}).reduce("",combine: {$0 + "," + $1}) as NSString).substringFromIndex(1) + "\n"
})
let csvString = csvArray.reduce("",combine: +)
return csvHeaderString+csvString
}
现在,在代码中的其他地方,您需要从此字符串创建NSData并将其添加到邮件编辑器：
let csvString = ..... let data = csvString.dataUsingEncoding(NSUTF8StringEncoding) let composer = MFMailComposeViewController() composer.addAttachmentData(attachment: data,mimeType mimeType: "text/csv",fileName filename: "mydata.csv")
然后,用作曲家(设置正文,主题等)做常用的东西并将其呈现给用户！
编辑：
编辑答案以更好地回答这个问题.
