如何从文件夹下载文件？

Question

我想在文件夹“tracks”中的documentsDirectory中下载一个文件。但是，如果我使用此代码（文件下载在documentsDirectory中）。一切正常

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *filePath = [documentsDirectory stringByAppendingPathComponent:@"Chapter.mp3"];
BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:filePath isDirectory:false];

NSString *stringURL = @"link";
NSURL  *url = [NSURL URLWithString:stringURL];
NSData *urlData = [NSData dataWithContentsOfURL:url];
[urlData writeToFile:filePath atomically:YES];

如果我使用此代码（文件下载在文件夹“track”中的文件目录中），则不会下载文件

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *filePath = [documentsDirectory stringByAppendingPathComponent:@"tracks/Chapter.mp3"];
BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:filePath isDirectory:false];

NSString *stringURL = @"link";
NSURL  *url = [NSURL URLWithString:stringURL];
NSData *urlData = [NSData dataWithContentsOfURL:url];
[urlData writeToFile:filePath atomically:YES];

如何下​​载文件夹“tracks”中的documentsDirectory中的文件？

Answer 1

track文件夹可能尚不存在。你需要这样的东西：

NSError *error = nil;
NSString *tracksPath = [documentsDirectory stringByAppendingPathComponent:@"tracks];
if (![[NSFileManager defaultManager] fileExistsAtPath:tracksPath]) {
    [[NSFileManager defaultManager] createDirectoryAtPath:tracksPath withIntermediateDirectories:NO attributes:nil error:&error];
}