从iPad应用内通过电子邮件发送后，sqlite数据库无数据

Question

I have an iPad app for my clients, and now I need to add a feature in the app that they could click a button to bring the email program and send their sqlite database used by the app to me for problem diagnosing. I followed apple's sample app and it worked fine. I got the email sent with the attached db file. After I download the file from email and open it in SQLite Manager(Firefox), all the table schema is correct, however there is no data. Does anyone know what the problem is? The db file I downloaded has exactly the same size as it was from the device. Thanks.

Class mailClass = (NSClassFromString(@"MFMailComposeViewController"));

if (mailClass != nil)
{

   // check whether the current device is configured for sending emails

   if ([mailClass canSendMail])
  {
        MFMailComposeViewController *picker = [[MFMailComposeViewController alloc] init];
        picker.mailComposeDelegate = self;

        [picker setSubject:@"database file from ios app"];


        // Set up recipients
        NSArray *toRecipients = [NSArray arrayWithObject:@"someEmailAddress@gmail.com"];

        [picker setToRecipients:toRecipients];

        // Attach db file to the email
        NSString *path = [[NSBundle mainBundle] pathForResource:@"MyDB" ofType:@"sqlite"];
        NSData *myData = [NSData dataWithContentsOfFile:path];
        [picker addAttachmentData:myData mimeType:@"application/x-sqlite3" fileName:@"MyDB.sqlite"];

        // Fill out the email body text
        NSString *emailBody = @"test email with db";

        [picker setMessageBody:emailBody isHTML:NO];
        picker.modalPresentationStyle = UIModalPresentationFormSheet;
        [self presentModalViewController:picker animated:YES];

        [picker release];
    }
    else // email not configured
    {
        // Alert email is not configured
    }
}
else // older iOS
{
      // Alert OS is too old
}

Answer 1

The code you posted is reading the database file from the app's resource bundle. This is a read-only file originally shipped with the app.

You need to get the writable database file that has the actual data. Perhaps you have this in the Documents directory (or some other writable sandbox directory).

BTW - why are you checking for the MFMailComposeViewController class? It has existed since iOS 3.0. I doubt your app needs to support iOS 2.x (or even 3.x).