iOS5编程－－官方例子代码研究－－6.MailComposer

本文档版权归NickTang所有，没有本人书面或电子邮件允许，不许转载，摘录，发表。多谢！

我们很多时候需要在iOS程序中内置邮件发送功能，而这个例子基本上提供了我们所需要的所有功能。

注意一下几点

1.这个程序必须在设备上运行，关于如何在设备上运行程序，不是本文需要讲的，我会在以后的文章中讲述。

2.你的设备必须配置好一个邮件帐户，不然你没法看到好的效果。

3.关于如何发送多个附件，我会在最后提到。

4.基本的代码不会再分析，基础部分请看我前面的文章。

5.在你自己建立的工程中，比如加入后面这个framework：MessageUI.framework

分析代码如下：

1.

-(IBAction)showPicker:(id)sender

{

// This sample can run on devices running iPhone OS 2.0 or later

// The MFMailComposeViewController class is only available in iPhone OS 3.0 or later.

// So, we must verify the existence of the above class and provide a workaround for devices running

// earlier versions of the iPhone OS.

// We display an email composition interface if MFMailComposeViewController exists and the device can send emails.

// We launch the Mail application on the device, otherwise.

//上面的解释的非常清楚，关于这些类和api在那个版本中引入，必须加以关注。

//下面是一个动态运行期查询类名的一个很好的例子，不解释了，因为在前面的文章有解释到。

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

if (mailClass != nil)

{

// We must always check whether the current device is configured for sending emails

if ([mailClass canSendMail])

{

[self displayComposerSheet];

}

else

{

[self launchMailAppOnDevice];

}

}

else

{

[self launchMailAppOnDevice];

}

}

所以重点关注函数displayComposerSheet：

-(void)displayComposerSheet

{

MFMailComposeViewController *picker = [[MFMailComposeViewController alloc] init];

picker.mailComposeDelegate = self;

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

// Set up recipients

NSArray *toRecipients = [NSArray arrayWithObject:@"[e-mail]"];

NSArray *ccRecipients = [NSArray arrayWithObjects:@"[e-mail]", @"[e-mail]", nil];

NSArray *bccRecipients = [NSArray arrayWithObject:@"[e-mail]"];

[picker setToRecipients:toRecipients];

[picker setCcRecipients:ccRecipients];

[picker setBccRecipients:bccRecipients];

// Attach an image to the email

NSString *path = [[NSBundle mainBundle] pathForResource:@"rainy" ofType:@"png"];

NSData *myData = [NSData dataWithContentsOfFile:path];

[picker addAttachmentData:myData mimeType:@"image/png" fileName:@"rainy"];

//代码非常清楚，我也不加以解释了，注意下面这个注释掉的地方，很多人问如何发送多个附件，就是下面演示的这样就可以多加一个附件，

//既多次调用addAttachmentData:fileName:

/*path = [[NSBundle mainBundle] pathForResource:@"circle" ofType:@"png"];

myData = [NSData dataWithContentsOfFile:path];

[picker addAttachmentData:myData mimeType:@"image/png" fileName:@"circle"];*/

// Fill out the email body text

NSString *emailBody = @"It is raining in sunny California!";

[picker setMessageBody:emailBody isHTML:NO];

[self presentModalViewController:picker animated:YES];

[picker release];

}

在点击发送后，协议

MFMailComposeViewControllerDelegate

的下面这个函数会被调用。

- (void)mailComposeController:(MFMailComposeViewController*)controller didFinishWithResult:(MFMailComposeResult)result error:(NSError*)error

{

message.hidden = NO;

// Notifies users about errors associated with the interface

switch (result)

{

case MFMailComposeResultCancelled:

message.text = @"Result: canceled";

break;

case MFMailComposeResultSaved:

message.text = @"Result: saved";

break;

case MFMailComposeResultSent:

message.text = @"Result: sent";

break;

case MFMailComposeResultFailed:

message.text = @"Result: failed";

break;

default:

message.text = @"Result: not sent";

break;

}

[self dismissModalViewControllerAnimated:YES];

}

上面的这个代码也是很简单的，所以也不再解释。