即将开发一款iOS邮箱客户端, 大家有什么推荐的资料以供参考?o(╯□╰)o

就是想先行了解一些关于邮箱这一块的相关知识, 邮件收发的原理什么的?求大神解答

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http://www.raywenderlich.com/1980/email-tutorial-for-ios-how-to-import-and-export-app-data-via-email-in-your-ios-app

通常我们极力推荐浏览苹果的官方文档

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iPhone API已经提供了系统写邮件界面的接口,使用MFMailComposeViewController，用来显示界面.

项目中需要添加MessageUi.framework。
头文件加入

MFMailComposeViewControllerDelegate
#import <MessageUI/MessageUI.h>

sendMailViewController.m文件的实现：

- (void)viewDidLoad
{
    UIButton *button = [UIButton buttonWithType: UIButtonTypeRoundedRect];
    button.frame = CGRectMake(0, 40, 320, 50);
    [button setTitle: @"Mail" forState: UIControlStateNormal];
    [button addTarget: self action: @selector(sendEMail) forControlEvents: UIControlEventTouchUpInside];
    [self.view addSubview: button];
}

- (void) alertWithTitle: (NSString *)_title_ msg: (NSString *)msg 
{
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:_title_ 
                                                    message:msg 
                                                   delegate:nil 
                                          cancelButtonTitle:@"确定"
                                          otherButtonTitles:nil];
    [alert show];
    [alert release];
} 

//点击按钮后，触发这个方法
-(void)sendEMail 
{
    Class mailClass = (NSClassFromString(@"MFMailComposeViewController"));

    if (mailClass != nil)
    {
        if ([mailClass canSendMail])
        {
            [self displayComposerSheet];
        } 
        else
        {
            [self launchMailAppOnDevice];
        }
    } 
    else
    {
        [self launchMailAppOnDevice];
    }    
}
//可以发送邮件的话
-(void)displayComposerSheet 
{
    MFMailComposeViewController *mailPicker = [[MFMailComposeViewController alloc] init];

    mailPicker.mailComposeDelegate = self;

    //设置主题
    [mailPicker setSubject: @"eMail主题"];

    // 添加发送者
    NSArray *toRecipients = [NSArray arrayWithObject: @"first@example.com"];
    //NSArray *ccRecipients = [NSArray arrayWithObjects:@"second@example.com", @"third@example.com", nil];
    //NSArray *bccRecipients = [NSArray arrayWithObject:@"fourth@example.com", nil];
    [mailPicker setToRecipients: toRecipients];
    //[picker setCcRecipients:ccRecipients];    
    //[picker setBccRecipients:bccRecipients];

    // 添加图片
    UIImage *addPic = [UIImage imageNamed: @"123.jpg"];
    NSData *imageData = UIImagePNGRepresentation(addPic);            // png
    // NSData *imageData = UIImageJPEGRepresentation(addPic, 1);    // jpeg
    [mailPicker addAttachmentData: imageData mimeType: @"" fileName: @"123.jpg"];

    NSString *emailBody = @"eMail 正文";
    [mailPicker setMessageBody:emailBody isHTML:YES];

    [self presentModalViewController: mailPicker animated:YES];
    [mailPicker release];
}
-(void)launchMailAppOnDevice
{
    NSString *recipients = @"mailto:first@example.com&subject=my email!";
    //@"mailto:first@example.com?cc=second@example.com,third@example.com&subject=my email!";
    NSString *body = @"&body=email body!";

    NSString *email = [NSString stringWithFormat:@"%@%@", recipients, body];
    email = [email stringByAddingPercentEscapesUsingEncoding: NSUTF8StringEncoding];

    [[UIApplication sharedApplication] openURL: [NSURL URLWithString:email]];
}
- (void)mailComposeController:(MFMailComposeViewController *)controller 
          didFinishWithResult:(MFMailComposeResult)result error:(NSError *)error 
{
    NSString *msg;

    switch (result) 
    {
        case MFMailComposeResultCancelled:
            msg = @"邮件发送取消";
            break;
        case MFMailComposeResultSaved:
            msg = @"邮件保存成功";
            [self alertWithTitle:nil msg:msg];
            break;
        case MFMailComposeResultSent:
            msg = @"邮件发送成功";
            [self alertWithTitle:nil msg:msg];
            break;
        case MFMailComposeResultFailed:
            msg = @"邮件发送失败";
            [self alertWithTitle:nil msg:msg];
            break;
        default:
            break;
    }

    [self dismissModalViewControllerAnimated:YES];
}