无法识别的选择器,但调试可以看到它

以下是收集方法:

...
//predicate is a boolean method that accepts an object as its single parameter
-(id<Notation>) getFirstChildMatching: (SEL) predicate declaredInInstance:(id) instance
{
    NSMethodSignature *sig = [[instance class] instanceMethodSignatureForSelector:predicate];
    NSInvocation *myInvocation = [NSInvocation invocationWithMethodSignature:sig];
    [myInvocation setTarget:instance];
    [myInvocation setSelector:predicate];

    int numItems = childNotations.count;
    for(int i=0;i< numItems;i++)
    {
        id<Notation> thisNotation = [childNotations objectAtIndex:i];
        [myInvocation setArgument:thisNotation atIndex:2];
        BOOL result =NO;
        [myInvocation retainArguments];
        [myInvocation invoke];
        [myInvocation getReturnValue:&result];

        if (result)
            return thisNotation;

    }

    return nil;
}

以下是测试方法和谓词:

- (void) testGetFirstChildMatching
{
    Leaf *line1 = [[Leaf alloc] initWithValue:1 step:Step_A andNumber:1];
    Leaf *line2 = [[Leaf alloc] initWithValue:2 step:Step_B andNumber:2];

    SEL mySelector = @selector(valueIs1:);

    id<CompositeNotation> compositeNotation = [[CompositeNotation alloc] init];
    [compositeNotation addNotation:line1];
    [compositeNotation addNotation:line2];

    id notation = [compositeNotation getFirstChildMatching: mySelector declaredInInstance:self];
    STAssertEquals(YES, [notation isKindOfClass:[Leaf class]], @"Should be of type Leaf: %@", notation);
    //Leaf *found = ((Leaf *)notation);
    STAssertEquals([notation value], line1.value, @"Should have found line 1 with value 1: actual %i", [notation value]);
    [line1 release];
    [line2 release];
}

-(BOOL) valueIs1: (Leaf *) leaf
{
    if (leaf.value == 1)
        return YES;

    return NO;
}

有什么想法吗?

顺便说一句,Leaf实现了表示法协议