将 MFMailComposeViewController 推送到导航堆栈上?未以模态方式呈现

Pushing an MFMailComposeViewController onto the navigation stack? Not presented modally(将 MFMailComposeViewController 推送到导航堆栈上?未以模态方式呈现)

问题描述

我有一个表格视图，在其中一个单元格中显示联系人".选择此单元格后，我想推入一个 MFMailComposeViewController.

I have a table view, and in one of the cells, it says "contact". Upon selecting this cell, I'd like to push in a MFMailComposeViewController.

我似乎只能以模态方式呈现这个 MFMailComposeViewController.这里有什么问题?

I can only seem to present this MFMailComposeViewController modally. What is the problem here?

谢谢！

相关代码片段:

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {


    MFMailComposeViewController *controller = [[MFMailComposeViewController alloc] init];
    //*works*//[self.navigationController presentModalViewController:controller animated:YES];
    //*broken*//[self.navigationController pushViewController:controller animated:YES];

}

我得到的错误是:" * 由于未捕获的异常 'NSInvalidArgumentException' 导致应用程序终止，原因:'不支持推送导航控制器'* 在第一次抛出时调用堆栈:"

The error that I get is: " * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Pushing a navigation controller is not supported' * Call stack at first throw:"

所以看起来我已经有了一个导航控制器，并且由于 MFMailComposeViewController 是 UINavigationController 的子类，我正在将一个导航控制器推到另一个导航控制器上?

So it looks like I have a navigationController already, and since MFMailComposeViewController is a subclass of UINavigationController, I'm pushing a navController onto another navController?

我希望我的 UI 保持一致，因此我想将 MFMailComposeViewController 推送到导航堆栈上，而不是模态显示它.

I want my UI to be consistent, so I want to push a MFMailComposeViewController onto the nav stack rather than present it modally.

推荐答案

这是因为 MFMailComposeViewController 不是 UIViewController 的子类，而是 UINavigationController代码>.当您尝试将 UINavigationController 或 UINavigationController 的子类推送到现有堆栈时，UINavigationController 会引发异常.允许以模态方式呈现 UINavigationController.

This is because MFMailComposeViewController isn't a subclass of UIViewController but of UINavigationController. UINavigationController throws an exception when you're attempting to push a UINavigationController or subclass of UINavigationController onto an existing stack. Presenting a UINavigationController modally is permitted.

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