UIPopover 中的 UIDatePicker

Question

我搜索了整个互联网（也许我有点夸张），寻找有关如何将 DatePicker 放入 UIPopover 并在 iPad 应用程序中显示它的教程。我尝试创建一个视图控制器，将日期选择器放入视图控制器中，然后：

self.popover = [[UIPopoverController alloc] initWithContentViewController:sa];

（sa 是我创建的视图控制器的名称），但这不起作用，应用程序崩溃了。有人可以帮忙吗？

Answer 1

尝试使用下面的代码。它将正常工作：

Objective-C

- (IBAction)showDatePicker:(UIButton *)sender {
    UIDatePicker *datePicker = [[UIDatePicker alloc]init];//Date picker
    datePicker.frame = CGRectMake(0, 0, 320, 216);
    datePicker.datePickerMode = UIDatePickerModeDateAndTime;
    [datePicker setMinuteInterval:5];
    [datePicker addTarget:self action:@selector(dateChanged:) forControlEvents:UIControlEventValueChanged];//need to implement this method in same class


    UIView *popoverView = [[UIView alloc] init];   //view
    popoverView.backgroundColor = [UIColor clearColor];
    [popoverView addSubview:datePicker];
    // here you can add tool bar with done and cancel buttons if required

    UIViewController *popoverViewController = [[UIViewController alloc] init];
    popoverViewController.view = datePicker;
    popoverViewController.view.frame = CGRectMake(0, 0, 320, 216);
    popoverViewController.modalPresentationStyle = UIModalPresentationPopover;
    popoverViewController.preferredContentSize = CGSizeMake(320, 216);
    popoverViewController.popoverPresentationController.sourceView = sender; // source button
    popoverViewController.popoverPresentationController.sourceRect = sender.bounds; // source button bounds
    //popoverViewController.popoverPresentationController.delegate = self;
    [self presentViewController:popoverViewController animated:YES completion:nil];
}
- (void)dateChanged:(UIDatePicker *)datePicker {
    NSLog(@"DATE :: %@", datePicker.date);
}

Swift 4.2

 @IBAction func showDatePicker(_ sender: UIButton) {
    let datePicker = UIDatePicker()//Date picker
    let datePickerSize = CGSize(width: 320, height: 216) //Date picker size
    datePicker.frame = CGRect(x: 0, y: 0, width: datePickerSize.width, height: datePickerSize.height)
    datePicker.datePickerMode = .dateAndTime
    datePicker.minuteInterval = 5
    datePicker.addTarget(self, action: #selector(dateChanged(_:)), for: .valueChanged)

    let popoverView = UIView()
    popoverView.backgroundColor = UIColor.clear
    popoverView.addSubview(datePicker)
    // here you can add tool bar with done and cancel buttons if required

    let popoverViewController = UIViewController()
    popoverViewController.view = popoverView
    popoverViewController.view.frame = CGRect(x: 0, y: 0, width: datePickerSize.width, height: datePickerSize.height)
    popoverViewController.modalPresentationStyle = .popover
    popoverViewController.preferredContentSize = datePickerSize
    popoverViewController.popoverPresentationController?.sourceView = sender // source button
    popoverViewController.popoverPresentationController?.sourceRect = sender.bounds // source button bounds
    popoverViewController.popoverPresentationController?.delegate = self // to handle popover delegate methods 
    self.present(popoverViewController, animated: true, completion: nil)

    }
    @objc func dateChanged(_ datePicker: UIDatePicker) {
        print("DATE :: \(datePicker.date)")
    }

如果您在视图控制器中分别实现以下委托，则相同的代码也适用于 iPhone

extension YourViewController : UIPopoverPresentationControllerDelegate {
    func adaptivePresentationStyle(for controller: UIPresentationController) -> UIModalPresentationStyle {
        // Force popover style
        return UIModalPresentationStyle.none
    }
}

Answer 2

现在，既然您已经标记了 iPhone，那么可以清楚地假设您正在尝试在 iPhone 中使用 UIPopoverController，但是 UIPopoverController仅适用于 iPad。由于 iPhone 无法识别该控制器，因此会导致崩溃。