fileExistsAtPath对于存在的目录返回NO.如果我有以下代码：
NSURL *newDirectoryPath = ... // path does not begin with a tilda
// and is created using URLByAppendingPathComponent:isDirectory:
BOOL directoryExists = [self.fileManager fileExistsAtPath:[newDirectoryPath absoluteString]];
if (NO == directoryExists)
{
BOOL ret = [self.fileManager moveItemAtURL:self.currentPresentationDirectoryPath toURL:newDirectoryPath error: &err];
// ret is YES,err is nil
directoryExists = [self.fileManager fileExistsAtPath:[newDirectoryPath absoluteString]];
}
即使刚刚使用moveItemAtURL成功创建了目录,fileExistsAtPath仍然返回NO.
我知道文档说这个：
Attempting to predicate behavior based on the current state of the
file system or a particular file on the file system is not
recommended. Doing so can cause odd behavior in the case of file
system race conditions.
但我想了解这里的问题 – 如果我关闭应用程序并重新启动它,那么上面代码中对fileExistsAtPath的第一次检查仍然返回NO,即使该代码先前在代码的执行过程中已成功创建,我可以在管理器中看到该目录,我也可以成功地从目录的内容等中读取.
附：有没有fileExistsAtURL：方法？
解决方法
如果您有NSURL,-absoluteURL将不会返回NSFileManager的可用路径.它将使用file：//前缀返回绝对URL.例如：file：/// path / to / file.
而是尝试使用其他方法,如-path.检查是否有效.
NSURL *myURL = /* some url */;
NSString *myPath;
BOOL exi;
myPath = [myURL path];
exi = [[NSFileManager defaultManager] fileExistsAtPath:myPath];
if(!exi) {
NSLog(@"File does not exist");
}
