传递本地指针到performSelectorOnMainThread的withObject参数？ [英] Passing a native pointer to performSelectorOnMainThread's withObject argument?
问题描述
我想传递一个C ++对象到使用performSelectorOnMainThread调用的选择器。简单地将指针转换为一个'id'（objc_object *）似乎不工作。
我总是可以写我自己的目标C包装类，但应该有一个相当标准的方式做到这一点。
I want to pass a point to a C++ object to the selector invoked using performSelectorOnMainThread. Simply casting the pointer to an 'id' (objc_object*) doesn't seem to work. I could always write my own objective C wrapper class, but there should be a fairly standard way of doing this. I didn't really find anything on apple's documentation for it though.
这是最好的方法是什么？
What's the best way to do this?
这里是我想做的：
...
Foo *foo = new Foo(); // Foo is a C++ class
MyObject *myObj = [[MyObject alloc] init]; // Obj-C class
[myObj performSelectorOnMainThread:@selector(someMethod:) withObject:foo waitUntilDone:NO];
...
谢谢！
推荐答案
不需要创建自己的包装类; [NSValue valueWithPointer：]是为拳击指针设计的。只要让someMethod取一个NSValue而不是一个原始指针，然后用pointerValue提取指针。
No need to make your own wrapper class; [NSValue valueWithPointer:] is designed for boxing pointers. Just make someMethod take an NSValue rather than a raw pointer, and then extract the pointer with pointerValue.
（我相信performSelector *方法保留他们的参数，保证通过调用持续，这就是为什么你不能只是将随机值转换为该参数中的id。）
(I believe that the performSelector* methods retain their arguments so that the object is guaranteed to last through the call, which is why you can't just cast a random value to an id in that argument.)
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