Resolving Attachment Issues in iPhone Mails: A Step-by-Step Guide

Understanding Attachment Issues with iPhone Mails

When sending emails through an iPhone application, users often face issues where the attachment is not displayed as expected. In this article, we will delve into the reasons behind such behavior and explore possible solutions to resolve the issue.

The Problem Behind the Issue

The problem arises when the email client fails to properly attach a file to the email. This can be due to various reasons, including:

Incorrectly specified file path
Inadequate permissions for writing files to the app’s bundle or other directories
Failure to create a temporary file in the desired location

The Provided Code Snippet

The code snippet provided is from an IBAction method (btnPressedExport) which generates a CSV file and attempts to attach it to an email. However, there are several issues with this approach:

// Attach an image to the email
NSString *path = [[NSBundle mainBundle] pathForResource:@"myExport" ofType:@"csv"];
NSData *myData = [NSData dataWithContentsOfFile:path];

The path variable is set to a file in the app’s bundle, which is read-only. This means that the CSV file cannot be modified or attached to the email.
To create a temporary file and attach it to the email, a different approach should be taken.

A Corrected Approach

To resolve the attachment issue, we need to write the CSV file to a temporary location in the user’s Documents directory. This can be achieved using the NSSearchPathForDirectoriesInDomains method:

NSArray *sysPaths = NSSearchPathForDirectoriesInDomains( NSDocumentDirectory, NSUserDomainMask, YES );
NSString *docDirectory = [sysPaths objectAtIndex:0];
NSString *filePath = [NSString stringWithFormat:@"%@/myexport.csv", docDirectory];

Here’s the complete corrected code snippet:

-(IBAction)btnPressedExport:(id)sender{
    NSArray *x=[[NSArray alloc] initWithArray:[DatabaseAccess getAllTransactionsForUserID:[BudgetTrackerAppDelegate getUserID] profileID:[BudgetTrackerAppDelegate getProfileID]]];
    int i=-1,j=[x count];
    NSDictionary *tmp;
    NSMutableString *stringToWrite=[[NSMutableString alloc] init];

    for(;i<j;i++){
        if(i==-1){
            [stringToWrite appendString:@"TransactionID,TransactionDate,ProfileName,ProfileType,GroupName,GroupType,CategoryName,TransactionAmt\n"];
        } else {
            tmp=[x objectAtIndex:i];
            [stringToWrite appendFormat:@"%@,%@,%@,%@,%@,%@,%@,%@\n",
             [tmp valueForKey:@"TraID"],[tmp valueForKey:@"TraDate"],[tmp valueForKey:@"ProfileName"],[tmp valueForKey:@"ProfileType"],[tmp valueForKey:@"GroupName"],[tmp valueForKey:@"GroupType"],[tmp valueForKey:@"CatName"],[tmp valueForKey:@"TraAmt"]];
        }
    }

    [stringToWrite writeToFile:[self pathOfCSVForExport] atomically:YES encoding:NSStringEncodingConversionAllowLossy error:nil];

    picker = [[MFMailComposeViewController alloc] init];
    picker.mailComposeDelegate=self;

    [picker setSubject:@"Hello from Sugar!"];

    //Set up recipients
    NSArray *toRecipients = [NSArray arrayWithObject:@"<a>[email protected]</a>"]; 

    NSString *docDirectory = [NSSearchPathForDirectoriesInDomains( NSDocumentDirectory, NSUserDomainMask, YES ) objectAtIndex:0];
    NSString *filePath = [NSString stringWithFormat:@"%@/myexport.csv", docDirectory];

    NSArray *ccRecipients = [NSArray arrayWithObjects:@"<a>[email protected]</a>", @"<a>[email protected]</a>", nil]; 
    NSArray *bCcRecipients = [NSArray array]; 

    [picker addAttachmentData:[NSData dataWithContentsOfFile:filePath] ofType:@"csv" atIndex:0 error:nil];
    [picker setBodyString:[NSString stringWithFormat:@"CSV File: %@", filePath] isHTML:NO];

    [self presentViewController:picker animated:YES completion:nil];
}

-(NSString *)pathOfCSVForExport{
    NSArray *sysPaths = NSSearchPathForDirectoriesInDomains( NSDocumentDirectory, NSUserDomainMask, YES );
    NSString *docDirectory = [sysPaths objectAtIndex:0];
    return docDirectory;
}

Conclusion

By understanding the reasons behind attachment issues with iPhone mails and implementing a corrected approach to writing files to temporary locations in the user’s Documents directory, developers can effectively resolve such problems. This article provides valuable insights into the world of mobile app development and file attachments.

Last modified on 2024-02-23