MFMailComposeViewController 加载空白屏幕

Question

我正在运行 OS 3.1.3 的 iPod Touch 上进行测试，

试图允许用户从应用程序内发送电子邮件 - 但当执行以下代码时，整个屏幕会完全变成空白/白色。

关于为什么会发生这种情况有什么想法吗？ 我的项目中有MessageUI框架。 我在头文件中导入和委托：

#import <MessageUI/MessageUI.h>
#import <MessageUI/MFMailComposeViewController.h>
<MFMailComposeViewControllerDelegate>

这是代码，非常标准：

if ([MFMailComposeViewController canSendMail]) {
    MFMailComposeViewController *picker = [[MFMailComposeViewController alloc] init];
    picker.mailComposeDelegate = self;

    [picker setSubject:@"App Feedback"];
    [picker setToRecipients:[NSArray arrayWithObject:@"[email protected]"]];

    [self presentModalViewController:picker animated:YES];
    [picker release];
    }

然后我有 didFinishWithResult 函数，该函数会在发送电子邮件时关闭 ModalViewController。

但同样，我在 iPod Touch 上看到的只是空白的白屏。 =/

谢谢！

Answer 1

if([MFMailComposeViewController canSendMail]){

        MFMailComposeViewController *mail=[[MFMailComposeViewController alloc]init];
        mail.mailComposeDelegate=self;
        [mail setSubject:@"App Feedback"];          
        [mail setMessageBody:@"*your message  content*" isHTML:NO];
        [self presentModalViewController:mail animated:YES];
        [mail release];         
    }

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

}

Answer 2

你可以看一下苹果的示例代码：
http://developer.apple.com/library/ios/ #samplecode/MessageComposer/Listings/Classes_MessageComposerViewController_m.html

-(IBAction)showMailPicker:(id)sender {

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

if (mailClass != nil) {
        [self displayMailComposerSheet];

    if ([mailClass canSendMail]) {
        [self displayMailComposerSheet];
    }
    else {
        feedbackMsg.hidden = NO;
        feedbackMsg.text = @"Device not configured to send mail.";
    }
}
else    {
    feedbackMsg.hidden = NO;
    feedbackMsg.text = @"Device not configured to send mail.";
}

}

-(void)displayMailComposerSheet
{
MFMailComposeViewController *picker = [[MFMailComposeViewController alloc] init];
picker.mailComposeDelegate = 自我;

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



NSArray *toRecipients = [NSArray arrayWithObject:@"[email protected]"]; 
NSArray *ccRecipients = [NSArray arrayWithObjects:@"[email protected]", @"[email protected]", nil]; 
NSArray *bccRecipients = [NSArray arrayWithObject:@"[email protected]"]; 

[picker setToRecipients:toRecipients];
[picker setCcRecipients:ccRecipients];  
[picker setBccRecipients:bccRecipients];


NSString *path = [[NSBundle mainBundle] pathForResource:@"rainy" ofType:@"jpg"];
NSData *myData = [NSData dataWithContentsOfFile:path];
[picker addAttachmentData:myData mimeType:@"image/jpeg" fileName:@"rainy"];


NSString *emailBody = @"It is raining in sunny California!";
[picker setMessageBody:emailBody isHTML:NO];

[self presentModalViewController:picker animated:YES];
[picker release];

}
- (void)mailComposeController:(MFMailComposeViewController*)控制器
didFinishWithResult:(MFMailComposeResult)结果错误:(NSError*)错误 {

feedbackMsg.hidden = NO;
// Notifies users about errors associated with the interface
switch (result)
{
    case MFMailComposeResultCancelled:
        feedbackMsg.text = @"Result: Mail sending canceled";
        break;
    case MFMailComposeResultSaved:
        feedbackMsg.text = @"Result: Mail saved";
        break;
    case MFMailComposeResultSent:
        feedbackMsg.text = @"Result: Mail sent";
        break;
    case MFMailComposeResultFailed:
        feedbackMsg.text = @"Result: Mail sending failed";
        break;
    default:
        feedbackMsg.text = @"Result: Mail not sent";
        break;
}
[self dismissModalViewControllerAnimated:YES];

}