Question

我有一些重复的代码我试图重构：

if (_currentIndex >= [_questions count] - 1) {
    [patient setDate:[NSDate date]];
    ConfirmationViewController *confirmation = [self.storyboard instantiateViewControllerWithIdentifier:@"Confirmation"];
    [confirmation setPatient:patient];
    [confirmation setQuestions: _questions];
    [self.navigationController pushViewController:confirmation animated:YES];

} else if ([[_questions objectAtIndex:_currentIndex + 1] isEqualToString:@"date"]) {
    DateViewController *dateView = [self.storyboard instantiateViewControllerWithIdentifier:@"Date"];
    [dateView setPatient:patient];
    [dateView setQuestions: _questions];
    [dateView setCurrentIndex: _currentIndex + 1];
    [self.navigationController pushViewController:dateView animated:YES];
} else {
    QuestionViewController *nextQuestion = [self.storyboard instantiateViewControllerWithIdentifier:@"Question"];
    [nextQuestion setCurrentIndex:_currentIndex + 1];
    [nextQuestion setPatient:patient];
    [nextQuestion setQuestions: _questions];
    [self.navigationController pushViewController:nextQuestion animated:YES];
}

我想声明一个变量nextView，它可以是ConfirmationViewController，DateViewController或QuestionViewController，因为所有这些变量都包含setPatient:patient，[self.navigationController pushViewController...]和{ {1}}，只需在运行特定于案例的代码片段后调用该块，但由于它们都是不同的类型，我无法弄清楚如何声明这个＆＃39;视图＆＃39;变量（我主要是JS背景，所以我习惯[setQuestions:_questions] - 在顶部！）

Answer 1

让您的三个视图控制器实现一个通用协议：

@protocol BaseViewController
    @property (readwrite, copy) MyPatient *patient;
    @property (readwrite, copy) NSArray *questions;
@end;

@interface ConfirmationViewController : UITableViewController <BaseViewController>
...
@end
@interface DateViewController : UIViewController <BaseViewController>
...
@end
@interface QuestionViewController : UIViewController <BaseViewController>
...
@end

现在你可以创建一个BaseViewController类型的变量，并在条件之外设置公共属性：

UIViewController<BaseViewController> *vc;
if (_currentIndex >= [_questions count] - 1) {
    [patient setDate:[NSDate date]];
    vc = [self.storyboard instantiateViewControllerWithIdentifier:@"Confirmation"];
} else if ([[_questions objectAtIndex:_currentIndex + 1] isEqualToString:@"date"]) {
    vc = [self.storyboard instantiateViewControllerWithIdentifier:@"Date"];
    [vc setCurrentIndex: _currentIndex + 1];
} else {
    vc = [self.storyboard instantiateViewControllerWithIdentifier:@"Question"];
    [vc setCurrentIndex:_currentIndex + 1];
}
[vc setPatient:patient];
[vc setQuestions: _questions];
[self.navigationController pushViewController:vc animated:YES];

Answer 2

如果你可以保证它们都有一个patient并且它们都有questions那么你可以让它们全部从一个具有这些东西的UIViewController子类继承，或者让它们全部采用一个协议需要那些东西。就个人而言，我会选择UIViewController子类。

动态类型的视图控制器

2 个答案: