将对象从 Activity 传递到 Fragment 是通过引用传递 [英] Passing Objects from Activity to Fragments is Pass by Reference

问题描述

当我们使用 Serializable 和 Parcelable 在 activities 之间传递对象时，然后一个 对象的副本/值发送到接收 activity(典型的按值传递行为).

When we use Serializable and Parcelable to pass object between activities then a copy/value of the object is sent to the receiving activity(Typical Pass by value behaviour).

但是为什么当我们在 Bundle 中将对象作为 Parcelable 传递给 Fragments 时，由于某种原因它们被发送为 对象的引用而不是对象的副本/值(通过引用行为).我还没有检查过Serializable，但我相信它会是一样的.

But why is it that when we pass objects to Fragments as Parcelable inside Bundle, for some reason they are sent as reference of object instead of copy/value of the object (Pass by Reference behaviour).I haven't checked this out for Serializable but i believe it would be the same.

对象以相同的方式传递，为什么 Activity 接收 object 和 Fragment 接收它的方式不同?

The object is passed the same way so why is there a difference in how the Activity receives the object and how the Fragment receives it ?

推荐答案

但是为什么当我们在 Bundle 中将对象作为 Parcelable 传递给 Fragments 时，由于某种原因它们被作为对象的引用而不是对象的副本/值发送

But why is it that when we pass objects to Fragments as Parcelable inside Bundle, for some reason they are sent as reference of object instead of copy/value of the object

这不能保证.例如，如果您进行了配置更改，或者您的流程终止但用户很快返回到您的任务，您将获得一份副本.

That is not guaranteed. For example, if you undergo a configuration change, or your process is terminated but the user returns to your task quickly, you will get a copy.

对象以同样的方式传递，那么为什么 Activity 接收对象的方式和 Fragment 接收它的方式存在差异?

The object is passed the same way so why is there a difference in how the Activity receives the object and how the Fragment receives it ?

启动活动总是涉及 IPC，因此总是涉及跨进程边界复制数据.

Starting an activity always involves IPC, and therefore always involves copying data across process boundaries.

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