java - Why we need to serializable object for passing one activity to another activity in Android

Question

Can anybody please tell why we need to serializable object for passing one activity to another activity in android? Android is following Java syntax. In java we can pass object to another class without serializable.

Thanks

Answer 1

In ordinary java programs passing parameters(Object type), is kind of create a new handler to the object and giving to another method (In regular words passing the reference by value).

But when it comes in android, passing object references from activity to activity, where their states have to be persisted, is a serious headache.

One way you can do is create a static object in the first activity and access from the second, though this seems to be a easiest way, there is no guarantee that the system maintains the activity in the memory. Therefore the second activity may loose the object reference.

Other way, and the mostly recommended way is serializing(Kind of flatten the object) the object and pass with the intent as extra. In android there are two ways to serialize.

1. Implement the java's serializable interface
2. Implement the android's parcelable interface

However, on the android, there is a serious performance hit that comes with using serializable, the solution is using parcelable.

You can find a pretty good tutorial and explanation on android parcelable implementation here.