Question

我的应用程序显示列表中的PDF文件。我很难理解iOS中的文件管理。我在这里阅读了指南，但它没有帮助：https://developer.apple.com/library/mac//documentation/FileManagement/Conceptual/FileSystemProgrammingGuide/Introduction/Introduction.html#//apple_ref/doc/uid/TP40010672

我不知道如何访问/tmp文件夹来写入它。我想我需要NSURLConnection使用URLsForDirectory:inDomains:方法。但我不知道URLsForDirectory:inDomains:方法返回临时目录所需的参数以及如何将NSData*从NSURLConnection转换为PDF文件。

Answer 1

1）使用 NSURLConnection ：

NSURL *fileURL = [NSURL URLWithString:@"your url here"];
NSURLSession *session = [NSURLSession sharedSession];
[[session dataTaskWithURL:fileURL completionHandler:^(NSData *data,
                                                      NSURLResponse *response,
                                                      NSError *error)
{
    if(!error)
    {
        NSString *filePath = [NSTemporaryDirectory() stringByAppendingPathComponent:[response suggestedFilename]];
        [data writeToFile:filePath atomically:YES];
    }

}] resume];

或

2）使用 NSURLSession ：

NSURL *fileURL = [NSURL URLWithString:@"url here"]; NSURLSession *session = [NSURLSession sharedSession]; [[session dataTaskWithURL:fileURL completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) { if(!error) { NSString *filePath = [NSTemporaryDirectory() stringByAppendingPathComponent:[response suggestedFilename]]; [data writeToFile:filePath atomically:YES]; } }] resume];

参考：nsurlsession-tutorial链接。

Answer 2

使用以下代码获取存储在/tmp中的文件的文件路径：

NSURL *tmpDirURL = [NSURL fileURLWithPath:NSTemporaryDirectory() isDirectory:YES];        // get /tmp folder path

NSURL *fileURL = [[tmpDirURL URLByAppendingPathComponent:@"filename"] URLByAppendingPathExtension:@"jpg"];

NSLog(@"fileURL: %@", [fileURL path]);

Answer 3

相反，您可以将文件保存到/Documents文件夹，稍后在不需要时将其删除。

看看：

+(NSString *)writeDataToDocuments:(NSData *)data withFilename:(NSString *)filename{
    NSString *docsPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];
    NSString *filePath = [[NSString alloc] initWithString: [docsPath stringByAppendingPathComponent:filename]];
    [data writeToFile:filePath atomically:YES];
    return filePath;
}

Answer 4

NSData *dataPdf = [NSData dataWithContentsOfURL:pdfOnline.url];

//Get path directory
NSArray *paths =
NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,                              
NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];

//Create PDF_Documents directory
documentsDirectory = [documentsDirectory     
stringByAppendingPathComponent:@"PDF_Documents"];
[[NSFileManager defaultManager]    
createDirectoryAtPath:documentsDirectory withIntermediateDirectories:YES attributes:nil error:nil];

NSString *filePath = [NSString stringWithFormat:@"%@/%@",documentsDirectory, @"**PUT FILENAME YOU WANT**"];

[dataPdf writeToFile:filePath atomically:YES];

下载PDF文件并将其保存到临时目录iOS

4 个答案: