Question

我的getter和设置有问题，他们没有被调用。我以为我明白他们是如何工作的，但看起来我有问题...

我知道我在使用select按钮之前没有初始化DateRangeController视图，但是知道它的nil我可以在viewDidLoad中设置值。如果我必须初始化它如何设置nib文件等？

这是我的父屏幕，我在其中设置值并获取值

@interface PieChartViewController : UIViewController {
    DateRangeController *nextController;
}
@property (nonatomic, retain) DateRangeController *nextController;
@implementation PieChartViewController
@synthesize nextController;

-(void)viewWillAppear:(BOOL)animated {
    if ([nextController StartDate] == nil) {
        [nextController setStartDate:[NSDate date]];
    }

    // DBStartDate returns nil and yes convertNSDateToDBStringDate works !
    NSString* DBStartDate = [General convertNSDateToDBStringDate:
       [nextController StartDate]];
}
- (void) selectRangeButtonPressed {
    nextController = [[[DateRangeController alloc] 
        initWithNibName:@"DateRange" bundle:nil] autorelease];
    nextController.title = @"Date Range";   
}

继承我的选择/儿童屏幕。

@interface DateRangeController : UIViewController  {
NSDate *returnStartDate;
}
-(NSDate*) StartDate;
-(void)setStartDate:(NSDate*) value;
@end
@implementation DateRangeController
-(NSDate*) StartDate {
   return returnStartDate;
}
-(void)setStartDate:(NSDate*) value {
    if (value != returnStartDate) {
       [value retain];
       [returnStartDate release];
       returnStartDate = value;
       NSLog(@"StartDate=%@", returnStartDate);
    }
}
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)
       nibBundleOrNil {
   if ((self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil])) {
       // Custom initialization
       returnStartDate = nil;
   }
   return self;
}
- (void)dealloc {
   [returnStartDate release];
}

Answer 1

尝试将“value”与isEqualToDate - 函数进行比较，而不是“！=” - 运算符：

if(![value isEqualToDate: returnStartDate]) { ...}

编辑：如果你需要nextController将startDate存储在viewWillAppear中，你应该在分配startDate之前在那里（或者更好，在viewDidLoad中）而不是在buttonPressed - Method中初始化它。

Obj-C，为什么我的吸气剂和制定者不工作？

1 个答案: