iOS 之发送邮件的常用方法

#pragma mark - email  
- (void)showMailPicker
{
    Class mailClass = (NSClassFromString(@"MFMailComposeViewController"));
    if (mailClass != nil) {
        if ([mailClass canSendMail]) {
            [self displayMailComposerSheet];
        }else{
            [self launchMailAppOnDevice];
        }
    }else{
        [self launchMailAppOnDevice];
    }
}
- (void)displayMailComposerSheet
{
    MFMailComposeViewController *picker = [[MFMailComposeViewController alloc] init];
    picker.mailComposeDelegate = self;
    
    [self presentModalViewController:picker animated:YES];
    [picker release];
}
-(void)launchMailAppOnDevice
{
    NSString *recipients = @"mailto:[e-mail]?cc=[e-mail],[e-mail]&subject=my email!";
    //@"mailto:[e-mail]?subject=意见与反馈"
    NSString *body = @"&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];
}
- (void)alertWithTitle:(NSString *)title msg:(NSString *)message
{
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:title
                                                    message:message
                                                   delegate:nil
                                          cancelButtonTitle:@"确定"
                                          otherButtonTitles:nil];
    [alert show];
    [alert release];
}