無法成功從郵件下載圖像和PDF

Question

我是IOS開發的新手，在從mail下載附件時遇到問題。當我嘗試使用MailCore2 SDK將郵件中的圖像或PDF附件下載到文檔目錄時，下載成功。但是我的問題是下載的圖像或PDF不顯示任何內容（即）。它給我的文件是一個零字節的空文件.im能夠知道NSData問題是我使用writeToFile是不正確的，但是我無法解決它。請幫我。

這是我用來從郵件下載文件的代碼

MCOIMAPFetchContentOperation * op = [self.imapSession fetchMessageByUIDOperationWithFolder:@"INBOX" uid:[sender tag]];

[op start:^(NSError * error, NSData * data) {
    if ([error code] != MCOErrorNone) {
        return;
    }
    NSAssert(data != nil, @"data != nil");

    MCOMessageParser * msg = [MCOMessageParser messageParserWithData:data];

    if ([msg.attachments count] > 0)
    {
        MCOIMAPPart *part = [msg.attachments objectAtIndex:0];

        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

        NSString *saveDirectory = [paths objectAtIndex:0];
        NSLog(@"%@",part.filename);

        NSString *attachmentPath = [[saveDirectory stringByAppendingString:@"/Downloads"] stringByAppendingPathComponent:part.filename];

        if (fileExists) {
            UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Message"
                                                            message:@"Fail Existed in Download Path."
                                                           delegate:self
                                                  cancelButtonTitle:@"OK"
                                                  otherButtonTitles:nil];
            [alert show];
        }
        else{

            [msg.data writeToFile:attachmentPath atomically:YES];

            UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Message"
                                                            message:@"Download Success /n Saved in Downloads"
                                                           delegate:self
                                                  cancelButtonTitle:@"OK"
                                                  otherButtonTitles:nil];
            [alert show];
        }
        [self.tableView reloadData];
    }
}];

請幫助我擺脫這個問題，並告訴我我在哪里做錯了。

提前致謝。

Answer 1

我曾經這樣：

 MCOIMAPFetchContentOperation * op = [self.imapSession fetchMessageByUIDOperationWithFolder:@"INBOX" uid:[sender tag]]; [op start:^(NSError * error, NSData * data) { if ([error code] != MCOErrorNone) { return; } NSAssert(data != nil, @"data != nil"); MCOMessageParser * msg = [MCOMessageParser messageParserWithData:data]; if ([msg.attachments count] > 0) { MCOAttachment *attachment = [msg.attachments objectAtIndex:0]; NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *saveDirectory = [paths objectAtIndex:0]; NSLog(@"%@",attachment.filename); NSString *downLoadDirectory = [saveDirectory stringByAppendingString:@"/Downloads"]; if (![[NSFileManager defaultManager] fileExistsAtPath:downLoadDirectory]) { [[NSFileManager defaultManager] createDirectoryAtPath:downLoadDirectory withIntermediateDirectories:YES attributes:nil error:nil]; } NSString *attachmentPath = [downLoadDirectory stringByAppendingPathComponent:attachment.filename]; if ([[NSFileManager defaultManager] fileExistsAtPath:attachmentPath]) { UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Message" message:@"Fail Existed in Download Path." delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil]; [alert show]; } else { BOOL res = [[attachment data] writeToFile:attachmentPath atomically:YES]; if (res) { UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Message" message:@"Download Success /n Saved in Downloads" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil]; [alert show]; } } } }]; 

我希望它們是有用的。