Question

我尝试过滤错过@property BOOL的对象数组取决于此属性的值

我定义了：

NSPredicate *missedInvitationsPredicate = [NSPredicate predicateWithBlock: ^BOOL(CRGQuizInvitation* invitation, NSDictionary *bind){
    return invitation.missed == YES;
}];

但它失败了。我尝试了很多东西，比如使用predicateWithFormat，一个等号和许多其他东西。最后我通过将BOOL转换为NSNumber来解决它，但我仍然想知道它有什么问题。

Answer 1

我已经实现了它而没有转换为NSNumber。这是示例代码。

NSMutableArray *collection = [[NSMutableArray alloc] init];

for (int itemIndex = 0; itemIndex < 5; itemIndex++)
{
  CRGQuizInvitation *invitation = [[CRGQuizInvitation alloc] init];

  if (itemIndex %2 == 0)
  {
    invitation.missed = YES;
  }

  [collection addObject:invitation];
}

NSPredicate *missedInvitationsPredicate = [NSPredicate predicateWithBlock: ^BOOL(CRGQuizInvitation* invitation, NSDictionary *bind){
    return invitation.missed == YES;
}];

NSArray *trueValueObjCollection = [collection filteredArrayUsingPredicate: missedInvitationsPredicate];

NSLog(@"%@", trueValueObjCollection);

<强> CRGQuizInvitation

@interface CRGQuizInvitation : NSObject

@property (nonatomic, assign) BOOL missed;

@end

输出记录

<TestClass: 0x8f1d450>
<TestClass: 0x8f1e440>
<TestClass: 0x8f1e460>

NSPredicate因BOOL而失败

1 个答案: