objective-c - 为什么将 unsigned int 传递给 performSelector 会丢失位？

我试图将十六进制值作为无符号整数传递给使用动态链接的方法。我作为参数传递的值以某种方式被破坏了。怎么了？

- (void)callPerformSelector
{
    NSNumber *argument = [NSNumber numberWithUnsignedInt:(unsigned int)0xFFFFFFFF];
    SEL selector = NSSelectorFromString(@"testPerformSelector:");
    NSLog(@"testPerformSelector object %@", argument);
   [self performSelector:selector withObject:argument];
}

- (void)testPerformSelector:(unsigned int) arg1
{
    NSLog(@"testPerformSelector unsigned int %u", arg1);
    NSLog(@"testPerformSelector hex %X", arg1);
}

输出是:

testPerformSelector object 4294967295
testPerformSelector unsigned int 4294967283
testPerformSelector hex FFFFFFF3

最佳答案

因为它应该是:

- (void)callPerformSelector
{
    NSNumber *argument = @0xFFFFFFFF;
    SEL selector = @selector(testPerformSelector:);
    NSLog(@"testPerformSelector object %@", argument);
   [self performSelector:selector withObject:argument];
}

- (void)testPerformSelector:(NSNumber *) arg1
{
    NSLog(@"testPerformSelector unsigned int %u", arg1.unsignedIntValue);
}

unsigned int 和 NSNumber * 是两个不同的东西

关于objective-c - 为什么将 unsigned int 传递给 performSelector 会丢失位？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/40508865/