访问当前沙盒下的文件

+ (NSArray *) getAllFileNames:(NSString *)dirName{    // 获得此程序的沙盒路径    NSArray *patchs = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);        // 获取Documents路径    // [patchs objectAtIndex:0]    NSString *documentsDirectory = [patchs objectAtIndex:0];    NSString *fileDirectory = [documentsDirectory stringByAppendingPathComponent:@"%@", dirName];        NSArray *files = [[NSFileManager defaultManager] subpathsOfDirectoryAtPath:fileDirectory error:nil];    return files;}