變量消滅dismissViewController

Question

我有一個視圖控制器與日期選擇器，並將變量設置爲選擇日期。

當我關閉視圖控制器時，變量爲零。

有什麼建議嗎？當「完成」

DatePickerView代碼被按下（NSLogs顯示日期被分配到變量）：當我檢查的日期賦予

-(void)done:(id)sender 
{ 
    [self dismissViewControllerAnimated:YES completion:nil]; 

    AddEditFixturesTableViewController *fixtures = [[AddEditFixturesTableViewController alloc]init]; 

    fixtures.fixtureDateTime = pickerDateTime; 

    NSDateFormatter *formatter = [[NSDateFormatter alloc]init]; 
    [formatter setDateFormat:@"dd-MM-yyyy"]; 
    NSString *pickerDateTimeString = [formatter stringFromDate:pickerDateTime]; 
    NSLog(@"Picker Date: %@", pickerDateTimeString); 
    NSString *fixturesDateTimeString = [formatter stringFromDate:[fixtures fixtureDateTime]]; 
    NSLog(@"Fixture Date: %@", fixturesDateTimeString); 
} 

代碼（NSLogs顯示變量是空的）：

DatePickViewController *pickerView = [[DatePickViewController alloc]init]; 

NSDateFormatter *formatter = [[NSDateFormatter alloc]init]; 
[formatter setDateFormat:@"dd-MM-yyyy"]; 
NSString *fixturesDateTimeString = [formatter stringFromDate:fixtureDateTime]; 
NSLog(@"Fixture Date: %@", fixturesDateTimeString); 
NSString *pickerDateTime = [formatter stringFromDate:[pickerView pickerDateTime]]; 
NSLog(@"Picker Date: %@", pickerDateTime); 

Answer 1

你錯就錯在下面的代碼：

AddEditFixturesTableViewController *fixtures = [[AddEditFixturesTableViewController alloc]init]; 
fixtures.fixtureDateTime = pickerDateTime; 

在這裏，您初始化NE w AddEditFixturesTableViewController對象併爲其設置屬性。但是你必須將它設置爲你的存在對象。所以你必須使用委派。

首先你必須做的是添加協議。添加以下到您的DatePickViewController.h：

@protocol DatePickViewControllerDelegate <NSObject> 

- (void)setNewDate:(NSDate *)date; 

@end 

@interface DatePickViewController : UIViewController 

{ 
    IBOutlet UIDatePicker *datePicker; 
} 

@property (nonatomic, weak) id<DatePickViewControllerDelegate> delegate; 
@property (nonatomic, strong) IBOutlet UIDatePicker *datePicker; 
@property (nonatomic, strong) NSDate *pickerDateTime; 

-(IBAction)done:(id)sender; 
-(IBAction)dateChanged:(id)sender; 

@end 

現在解決您的done:方法。

- (void)done:(id)sender 
{ 
    [self dismissViewControllerAnimated:YES completion:nil]; 

    if (_delegate) { 
     [_delegate setNewDate:pickerDateTime]; 
    } 

    NSDateFormatter *formatter = [[NSDateFormatter alloc]init]; 
    [formatter setDateFormat:@"dd-MM-yyyy"]; 
    NSString *pickerDateTimeString = [formatter stringFromDate:pickerDateTime]; 
    NSLog(@"Picker Date: %@", pickerDateTimeString); 
    NSString *fixturesDateTimeString = [formatter stringFromDate:[fixtures fixtureDateTime]]; 
    NSLog(@"Fixture Date: %@", fixturesDateTimeString); 
} 

在你的AddEditFixturesTableViewController接口中添加委託方法。

@interface AddEditFixturesTableViewController : UITableViewController <UITextFieldDelegate, UITextViewDelegate, DatePickViewControllerDelegate> 

@property (nonatomic, strong) NSDate *fixtureDateTime; 

@property (nonatomic, strong) IBOutlet UILabel *label; 
- (IBAction)setDate:(id)sender; 
- (void)setNewDate:(NSDate)date; 

@end 

最後加的委託方法實現：

- (void)setNewDate:(NSDate *)date 
{ 
    fixtureDateTime = date; 
} 

它會幫助你。祝你好運！