ios - PopupViewController 将 null 返回给 ViewController

Question

我想将 datepicker.date 从 DatePickerPopupViewController 传递到我的 SensorvViewcontroller，如下所示。但是，它返回我“null”。我究竟做错了什么？我的代码如下:

#import "DatePopoverViewController.h"

@interface DatePopoverViewController ()

@end

@implementation DatePopoverViewController
@synthesize datePicker;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
    datePicker.date=[NSDate date];
}



@end

#import "SensorViewController.h"

@interface SensorViewController ()

@end
// this represent my button which triggers popupViewController

-(void)chooseDate
{

    if([popoverController isPopoverVisible])
    {
    [popoverController dismissPopoverAnimated:YES];

    }
    else
    {
        CGRect popRect=CGRectMake (900,1,1,1);
        //CGRect popRect=CGRectMake (tools.frame.origin.x,tools.frame.origin.y,50,50);
        popoverController.popoverContentSize =CGSizeMake(320,216);
        [popoverController presentPopoverFromRect:popRect inView:self.view permittedArrowDirections:UIPopoverArrowDirectionUp animated:YES];
        datepop=[[DatePopoverViewController alloc]init];
        NSDate *ali= datepop.datePicker.date;
        NSLog(@"%@",ali);
    }

}

   @end

Answer 1

这段代码:

    CGRect popRect=CGRectMake (900,1,1,1);
    //CGRect popRect=CGRectMake (tools.frame.origin.x,tools.frame.origin.y,50,50);
    popoverController.popoverContentSize =CGSizeMake(320,216);
    [popoverController presentPopoverFromRect:popRect inView:self.view permittedArrowDirections:UIPopoverArrowDirectionUp animated:YES];
    datepop=[[DatePopoverViewController alloc]init];
    NSDate *ali= datepop.datePicker.date;
    NSLog(@"%@",ali);

应该更像是:

    popoverController=[[DatePopoverViewController alloc]init];

    CGRect popRect=CGRectMake (900,1,1,1);
    //CGRect popRect=CGRectMake (tools.frame.origin.x,tools.frame.origin.y,50,50);
    popoverController.popoverContentSize =CGSizeMake(320,216);
    [popoverController presentPopoverFromRect:popRect inView:self.view permittedArrowDirections:UIPopoverArrowDirectionUp animated:YES];

并且您应该设置委托(delegate)关系或 block 回调，以便当用户实际选择日期时调用方法，您可以执行以下操作:

NSDate *ali= popoverController.datePicker.date;
NSLog(@"%@",ali);

或者，更好的是，弹出窗口 Controller 从选择器获取日期并将其作为参数传递给回调方法/ block 。

---

类似于(内联键入):

在弹出窗口中:

typedef void (^CompletionBlock) ();

@propertty (copy, nonatomic) CompletionBlock completionBlock;

 - (void)dateSelected {
    self.completion();
}

在源 Controller 中:

self.popoverController.completionBlock = ^{
    NSLog(@"%@", self.popoverController.datePicker.date);
};