如何检查Swift中Documents文件目录中是否存在文件？ [英] How to check if a file exists in the Documents directory in Swift?

问题描述

如何检查 Swift 中的Documents目录中是否存在文件？

How to check if a file exists in the Documents directory in Swift?

我正在使用 [。writeFilePath] 将图像保存到Documents目录的方法，我想在每次启动应用程序时加载它。但是如果没有保存的图像，我有一个默认图像。

I am using [ .writeFilePath ] method to save an image into the Documents directory and I want to load it every time the app is launched. But I have a default image if there is no saved image.

但是我无法理解如何使用 [func fileExistsAtPath（ _ :)] 功能。有人可以给出一个使用带有路径参数的函数的例子。

But I just cant get my head around how to use the [ func fileExistsAtPath(_:) ] function. Could someone give an example of using the function with a path argument passed into it.

我相信我不需要在那里粘贴任何代码，因为这是一个通用的题。任何帮助将不胜感激。

I believe I don't need to paste any code in there as this is a generic question. Any help will be much appreciated.

干杯

推荐答案

Swift 4.x 版本

    let path = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as String
    let url = NSURL(fileURLWithPath: path)
    if let pathComponent = url.appendingPathComponent("nameOfFileHere") {
        let filePath = pathComponent.path
        let fileManager = FileManager.default
        if fileManager.fileExists(atPath: filePath) {
            print("FILE AVAILABLE")
        } else {
            print("FILE NOT AVAILABLE")
        }
    } else {
        print("FILE PATH NOT AVAILABLE")
    }

Swift 3.x 版本

    let path = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as String
    let url = URL(fileURLWithPath: path)

    let filePath = url.appendingPathComponent("nameOfFileHere").path
    let fileManager = FileManager.default
    if fileManager.fileExists(atPath: filePath) {
        print("FILE AVAILABLE")
    } else {
        print("FILE NOT AVAILABLE")
    }

Swift 2.x 版本，需要使用 URLByAppendingPathComponent

    let path = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0] as String
    let url = NSURL(fileURLWithPath: path)
    let filePath = url.URLByAppendingPathComponent("nameOfFileHere").path!
    let fileManager = NSFileManager.defaultManager()
    if fileManager.fileExistsAtPath(filePath) {
        print("FILE AVAILABLE")
    } else {
        print("FILE NOT AVAILABLE")
    }

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