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“sending ‘const nsstring ’ to parameter of type ‘nsstring ’ discards qualifiers” warning

admin 11月 11, 2020 0

“sending ‘const NSString ’ to parameter of type ‘NSString ’ discards qualifiers” warning

在项目中碰到“sending ‘const NSString *’ to parameter of type ‘NSString *’ discards qualifiers” warning，代码如下：

NSString const * ShopListDidClickShopNotification = @"ShopListDidClickShopNotification";

[[NSNotificationCenter defaultCenter] addObserverForName:ShopListDidClickShopNotification object:nil queue:nil usingBlock:^(NSNotification *note) {
//..
}];

期初以为是常量ShopListDidClickShopNotification声明有误，左改右改都没用，后来发现是NSNotificationCenter的调用有问题，正确的方式应该为：

NSString const * ShopListDidClickShopNotification = @"ShopListDidClickShopNotification";

[[NSNotificationCenter defaultCenter] addObserverForName:(NSString *)ShopListDidClickShopNotification object:nil queue:nil usingBlock:^(NSNotification *note) {
     //...
}];