iPhone:performSelector与BOOL参数？

Question

有没有办法在选择器中发送BOOL？

[self performSelector:@selector(doSomething:) withObject:YES afterDelay:1.5];

或者我应该使用NSInvocation？有人可以写一个样品吗？

Answer 1

如果你不能改变目标方法签名来接受a NSNumber代替BOOL你可以使用NSInvocation而不是performSelector:

MyTargetClass* myTargetObject;
BOOL myBoolValue = YES; // or NO

NSMethodSignature* signature = [[myTargetObject class] instanceMethodSignatureForSelector: @selector( myMethodTakingBool: )];
NSInvocation* invocation = [NSInvocation invocationWithMethodSignature: signature];
[invocation setTarget: myTargetObject];
[invocation setSelector: @selector( myMethodTakingBool: ) ];
[invocation setArgument: &myBoolValue atIndex: 2];
[invocation invoke];

Answer 2

你可以使用NSNumber来包装bools类型:

BOOL myBool = YES;
NSNumber *passedValue = [NSNumber numberWithBool:myBool];
[self performSelector:@selector(doSomething:) withObject:passedValue afterDelay:1.5];

在选择器中,要获取bool值,请使用:

BOOL value = [recievedObject boolValue];

Answer 3

最简单的方法如下:

如果你有方法

-(void)doSomething:(BOOL)flag

并希望执行带有flag = NO使用的Selecor

[object performSelector:@selector(doSomething:) withObject:nil];

如果是flag = YES,您可以发送任何对象,例如@YES - 来自bool的数字

 [object performSelector:@selector(doSomething:) withObject:@YES];

注意:不要使用@NO!在bool参数的方法中,只有nil会被解释为NO.

Answer 4

在主线程中使用dispatch_after,如下所示:

dispatch_time_t delayTime = dispatch_time(DISPATCH_TIME_NOW, (_animationDuration+1) * NSEC_PER_SEC);
dispatch_after(delayTime, dispatch_get_main_queue(), ^{
    [self completeAnimation:NO];
});

Answer 5

如果你想传递NO,只有NO,你可以改为零

[self performSelector:@selector(doSomething:) withObject:0 afterDelay:1.5];

但请记住,只需工作为零,不用ARC编译,不允许隐式转换

Answer 6

另一种方法是传递nilfor NO和anything elseforYES

[self performSelector:@selector(doSomething :) withObject:nil];

doSomething for BOOL参数将具有NO值

-

[self performSelector:@selector(doSomething :) withObject:[NSNumber numberWithBool:YES]];

doSomething for BOOL参数将具有YES值

-

[self performSelector:@selector(doSomething :) withObject:[NSNumber numberWithBool:NO]];

doSomething for BOOL参数将具有YES值(甚至传递的数字为NO)