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标题: ios - 我们在 ARC 中创建对象的这两种方式之间有什么区别吗？ [打印本页]

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作者: 菜鸟教程小白    时间: 2022-12-13 08:55
标题: ios - 我们在 ARC 中创建对象的这两种方式之间有什么区别吗？

我想知道两者之间实际上有什么区别:

UIButton *deleteButton = [UIButton buttonWithType:UIButtonTypeCustom];
self.deleteButton = deleteButton;

和:

self.deleteButton = [UIButton buttonWithType:UIButtonTypeCustom];

当使用 ARC 时？

我看到很多人在第一种情况下写了很多代码，但我相信第二种方式更短，更清晰简洁。

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Best Answer-推荐答案

is there actually any difference between

是的，但是在编译器优化下，生成的二进制文件将是相同的。

UIButton *deleteButton，即UIButton __strong *deleteButton拥有该对象的所有权。

对象已在当前自动释放池中注册，因为 buttonWithType: 类方法不以“alloc”、“new”、“copy”或“mutableCopy”开头。

因此，

UIButton *deleteButton = [UIButton buttonWithType:UIButtonTypeCustom];

/*
 * The current Autorelease Pool has ownership of the object. retainCount=1
 * __strong deleteButton has ownership of the object as well. retainCount=2
 */

self.deleteButton = deleteButton;

/*
 * If self.deleteButton is strong property, it has ownership of the object too. retainCount=3
 * If self.deleteButton is weak property, it doesn't have ownership of the object. retainCount=2
 */

关于ios - 我们在 ARC 中创建对象的这两种方式之间有什么区别吗？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/31251139/

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