iPhone How-to：如何發送郵件

iPhone提供了內嵌的Mail應用以支持電子郵件相關操作，此外還提供了MFMailComposeViewController以實現了在當前應用內編輯和發送郵件。使用內嵌的Mail應用還是MFMailComposeViewController就取決于實際的需求了，實現方法分別是：

• 調用內嵌Mail應用

- (void) sendEmailTo:(NSString *)to withSubject:(NSString *)subject withBody:(NSString *)body {
    NSString *mailString = [NSString stringWithFormat:@"mailto:?to=%@&subject=%@&body=%@",
                            [to stringByAddingPercentEscapesUsingEncoding:NSASCIIStringEncoding],
                            [subject stringByAddingPercentEscapesUsingEncoding:NSASCIIStringEncoding],
                            [body stringByAddingPercentEscapesUsingEncoding:NSASCIIStringEncoding]];
    [[UIApplication sharedApplication] openURL:[NSURL URLWithString:mailString]];
}

需要注意的是這里使用了NSString的stringByAddingPercentEscapesUsingEncoding接口，其作用就是在URL字符串中進行特殊字符的替換，比如將空格替換成%20之類的。

• 使用MFMailComposeViewController支持應用內郵件發送

- (IBAction)sendMail{
    MFMailComposeViewController *controller = [[MFMailComposeViewController alloc] init];
    controller.mailComposeDelegate = self;
    [controller setSubject:@"In app email..."];
    [controller setMessageBody:@"...a tutorial from mobileorchard.com" isHTML:NO];
    [self presentModalViewController:controller animated:YES];
    [controller release];
}

此外還需要實現mailComposeController:didFinishWithResult:error:的協議以進行發送成功或者失敗后的處理:

- (void)mailComposeController:(MFMailComposeViewController*)controller didFinishWithResult:(MFMailComposeResult)result error:(NSError*)error {
    ...
    [self dismissModalViewControllerAnimated:YES];
}