Xcode 6:为什么这段代码现在不能编译?
问题描述:
我的代码被编译,直到我升级到Xcode的运行极大6.Xcode 6:为什么这段代码现在不能编译?
定义显示了一个警告:自动属性合成将不能合成属性“散”,因为它是“读写”,但它会通过合成“只读”另一个属性
@property (nonatomic, strong) NSString *hash; // (get/compute) hash code of the place (master hash of images)
实施显示错误,每当我访问_hash:未声明的标识符“_hash”的使用
-(NSString *)hash {
if (_hash) return _hash;
// If place id, take it as the hash code
NSString *poiID = self.info[@"id"];
if (poiID) {
_hash = [NSString stringWithFormat:@"id-%lu",(unsigned long)[self.address hash]];
}
else if (CLLocationCoordinate2DIsValid(self.location.coordinate)) {
NSString *seed = [NSString stringWithFormat:@"%f,%f", self.location.coordinate.latitude, self.location.coordinate.longitude];
_hash = [NSString stringWithFormat:@"location-%lu",(unsigned long)[seed hash]];
}
else if (self.address) {
NSString *seed = self.address;
_hash = [NSString stringWithFormat:@"address-%lu",(unsigned long)[seed hash]];
}
else {
_hash = @"POI-unknownIDLocationOrAddress";
}
return _hash;
}
答
你需要下面的行添加到自动生成setter方法:
@synthesize hash = _hash;
如果你不想setter方法,只需要一个只读属性:
@property (nonatomic, strong, readonly) NSString *hash;
好的。我们现在必须用@synthesize hash = _hash显式声明自动合成; – 2014-09-21 15:04:03
查看本节[何时提供实例变量](http://useyourloaf.com/blog/2012/08/01/property-synthesis-with-xcode-4-dot-4.html)来自2012年的关于Xcode 4.4的文章 – 2014-09-21 15:30:03