Question

我正在尝试将NSMutableDictionary applicationDidEnterBackground个AppDelegate.m中的plist保存到NSString *photoCacheFilename = @"photoCache.plist"; [photoDict writeToFile:photoCacheFilename atomically:YES]; NSLog(@"File name: %@", photoCacheFilename); BOOL isFile = [[NSFileManager defaultManager] fileExistsAtPath:photoCacheFilename]; if(isFile) { NSLog (@"File found"); NSMutableDictionary *newDictionary = [[NSMutableDictionary alloc] initWithContentsOfFile:photoCacheFilename]; } else { NSLog (@"File not found"); }文件中。保存后，我立即尝试检查文件是否存在并将其读回，但找不到该文件。

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsPath = [paths objectAtIndex:0];
NSString *photoCacheFilename = [documentsPath stringByAppendingPathComponent:@"photoCache.plist"];

[photoDict writeToFile:photoCacheFilename atomically:YES];

BOOL isFile = [[NSFileManager defaultManager] fileExistsAtPath:photoCacheFilename];
if(isFile)
{
    NSLog (@"File found");
    NSMutableDictionary *newDictionary = [[NSMutableDictionary alloc] initWithContentsOfFile:photoCacheFilename];
}
else
{
    NSLog (@"File not found");
}

我按照某些用户的建议修改了代码，但仍未找到该文件。我不确定我是否正确检查文件是否存在。

{{1}}

Answer 1

您没有指定Documents目录

的正确路径

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);  
NSString *documentsPath = [paths objectAtIndex:0];

NSString *photoCacheFilename = [documentsPath stringByAppendingPathComponent:@"photoCache.plist"]; // Correct path to Documents Dir in the App Sand box

[photoDict writeToFile:photoCacheFilename atomically:YES]; //Write

Answer 2

您必须指定保存数据的完整路径：

NSString *myFile = @"myFile.plist";
NSArray *filePaths = NSSearchPathForDirectoriesInDomains (NSDocumentDirectory,  NSUserDomainMask, YES);
NSString *documentsDirectory = [filePaths objectAtIndex:0];
NSString *path = [documentsDirectory stringByAppendingPathComponent:myFile];
[photoDict writeToFile:path atomically:YES];

Answer 3

IN SWIFT 3.0

获取文档目录中的photoCache.plist文件路径。

func getPath() -> String {
        let plistFileName = "photoCache.plist"
        let paths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)
        let documentPath = paths[0] as NSString
        let plistPath = documentPath.appendingPathComponent(plistFileName)
        return plistPath
    }

检查文件是否存在。

let plistPath = self.getPath()
if FileManager.default.fileExists(atPath: plistPath) {
   //File Exists
}

读取和编写NSMutableDictionary到plist文件

3 个答案: