我遇到了一个错误

Variable is not assignable (missing __block type specifier)

就行了aPerson =参与者；。如何确保 block 可以访问 aPerson 变量并且可以返回 aPerson 变量？

Person *aPerson = nil;

[participants enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {   
    Person *participant = (Person*)obj;

    if ([participant.gender isEqualToString:@"M"]) {
        aPerson = participant;
        *stop = YES;
    }
}];

return aPerson;

最佳答案

您需要使用这行代码来解决您的问题:

__block Person *aPerson = nil;

更多详情请引用本教程:Blocks and Variables

https://stackoverflow.com/questions/7962721/