当一些代码像这样：
objc_setAssociatedObject ( obj,&key,val,OBJC_ASSOCIATION_RETAIN );
我需要打电话给相关的
objc_setAssociatedObject ( obj,nil,OBJC_ASSOCIATION_RETAIN );
释放保留值？ Objective-C运行时是否自动释放dealloc或某处的关联引用？
解决方法
取消分配父对象时将释放关联对象.请参阅文档
here,特别是此示例：
At point 1,the string
overviewis still valid because theOBJC_ASSOCIATION_RETAINpolicy specifies that the array retains the associated object. When the array is deallocated,however (at point 2),overviewis released and so in this case also deallocated.
