问题描述
在我的应用程序中，MFMailComposeViewController 工作正常，但创建 MFMessageComposeViewController 的新实例失败.
In my application, MFMailComposeViewController works fine but creating a new instance of MFMessageComposeViewController fails.
这是两者的代码:
-( IBAction)sendSMS: (id)sender
{
MFMessageComposeViewController *picker = [[[MFMessageComposeViewController alloc] init] autorelease];
picker.messageComposeDelegate = self;
NSArray *toRecipients = [NSArray arrayWithObject: cell.currentTitle ];
picker.recipients = toRecipients;
[self presentModalViewController:picker animated:YES];
}
-( IBAction)sendEmail: (id)sender
{
MFMailComposeViewController *picker = [[[MFMailComposeViewController alloc] init] autorelease];
picker.mailComposeDelegate = self;
NSArray *toRecipients = [NSArray arrayWithObject: email.currentTitle ];
[picker setToRecipients:toRecipients];
[self presentModalViewController:picker animated:YES];
}
看起来一切都正确链接，因为电子邮件视图控制器工作正常.有什么我遗漏的东西可能是配置方面的吗?
Its seemingly obvious that everything is linking correctly because the email view controller works fine. Is there something I am missing maybe configuration wise?
推荐答案
你检查过+[MFMessageComposeViewController canSendText]吗?
来自 MFMessageComposeViewController 类参考,
在呈现消息组合视图之前，调用 canSendText 类方法以确保用户的设备已正确配置.如果 canSendText 方法返回 NO，请不要尝试显示消息组合视图.如果 SMS 传送不可用，您可以通知用户或直接在您的应用程序中禁用 SMS 功能.
Before presenting a message composition view, call the
canSendTextclass method to ensure that the user’s device is appropriately configured. Do not attempt to present a message composition view if the canSendText method returns NO. If SMS delivery isn’t available, you can notify the user or simply disable the SMS features in your application.
从 iOS 5 开始，您可以注册以通过 MFMessageComposeViewControllerTextMessageAvailabilityDidChangeNotification 通知的方式接收短信发送可用性更改的通知.
Starting in iOS 5, you can register to be notified of changes to the availability of text message sending by way of the MFMessageComposeViewControllerTextMessageAvailabilityDidChangeNotification notification.
可能返回 nil 的原因:
- 设备未运行 iOS 4.
- 设备是未启用 iMessage 的 iPod Touch/iPad.
- 没有 SIM 卡?(该视图现在显示在 iOS 6 中；应用不会收到消息发送失败的通知.)
- 设备"其实就是模拟器.(也许这也适用于 iOS 6.)
同样，[[MFMailComposeViewController alloc] init] 在未启用邮件帐户时返回 nil(您可以通过在设置中禁用帐户来快速测试)，但也会显示为您提供未配置邮件帐户"警报.MFMessageComposeViewController 不这样做.
Similarly, [[MFMailComposeViewController alloc] init] returns nil when no mail accounts are enabled (you can quickly test this by disabling accounts in Settings), but also shows a "No mail accounts configured" alert for you. MFMessageComposeViewController does not do this.
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