0

I'm trying to save a bunch of GPS locations in a text file on an iPhone. I've been following suggestions that I've gleaned from the web, but, while the app runs fine, no file is being created. At least, nothing is visible under XCode Window -> Devices and Simulators -> (app name).

The goal is to create a file named "1" in a folder called "position" under a folder named after the date/time the app is launched, which is in turn under the Document folder. Example: 2018-07-21-16-35-43/position/1

I'm writing this in Swift 4.2 in XCode 9.(latest)

I get the Document folder as follows (rideStart = Date()):

let urls = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)

if let docUrl = urls.first {
    let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = "yyyy-MM-dd-HH-mm-ss"
    let dateText = dateFormatter.string(from: rideStart)

    positionUrl = docUrl.appendingPathComponent(dateText)
}

When I'm ready to write out some lines of text I do the following (locationCache is an array of CLLocation objects, and textForFile is an extension property that formats the information I want as a comma-separated set of values, terminated with \r\n):

try? FileManager.default.createDirectory(at: positionUrl, withIntermediateDirectories: true)

let curUrl = positionUrl.appendingPathComponent("\(fileNumber)")

for loc in locationCache {
    do {
        let line = loc.textForFile
        print(line)
        try line.write(to: curUrl, atomically: true, encoding: .utf8)
        }
    catch {
        print(error)
    }
}

No errors are thrown when the code runs, and the text lines print to the console in the expected format.

I'm new to iOS and to Swift, the vast majority of my experience being in C# under Windows, along with javascript. I'm obviously missing something simple and/or basic. What am I doing wrong?

Additional Info

Based on feedback, I ran the app in a simulator. After figuring out where the iPhone 6 simulator was located in my Library folder, I determined that the file I was trying to create was, in fact, created (note: I'm currently using a FileHandle based approach to writing the file, as opposed to what's in the code shown in this posting -- but I've tested that FileHandle approach against the physical iPhone hardware, and it still doesn't create any file visible from within XCode's Devices and Simulators window.

Which brings up a point raised in the comments: is it even possible to examine the files on a connected/paired iPhone from within XCode? I thought from what I've read in various places that it should be possible...but that may not be the case.

Mark Olbert
  • 6,584
  • 9
  • 35
  • 69
  • 1. Your file will only have one line, the last line. `write` does not append, it replaces. 2. Other than that, your code looks fine. The file should be there. Print `curUrl.path` when running your app in a simulator and you will find the file at that path. – rmaddy Jul 22 '18 at 01:04
  • okay, I'll append rather than write. But I've looked at curUrl.path many times, and, at least when I'm running on an actual iPhone (which is all I've been doing, so far), there's nothing in the Devices and Simulators dialog. Which is very confusing. – Mark Olbert Jul 22 '18 at 01:20
  • If you run on a real device, the file is on the real device. You are not going to see it in Xcode. – rmaddy Jul 22 '18 at 01:37
  • I don't believe that's correct (e.g., https://stackoverflow.com/questions/6121613/browse-the-files-created-on-a-device-by-the-ios-application-im-developing-on-w, which, while dated, is very similar to what I've seen written about XCode 9, namely, that you can drill down thru Devices and Simulators on the Windows menu. – Mark Olbert Jul 22 '18 at 01:59

0 Answers0