different between versions 3.0.0 and 2.0.2

[Kadanza]

Hi

• 1) what improvement has version 3.0.0?

• 2) why need MutableLiveDataKtx instead MutableLiveData?

• 3) In version 2.0 we has great extension observe without Observer

livedata.observe(this) {it ->

}

In version 3.0 observe without Observer is gone =(
We have now only ugly

.observe(lifecycleOwner, Observer { result ->

})

• 4)

In version 2.0 I has unpleasant bug in android studio,
My breakpoint is skipped by android studio in extension observe, but code in worked

livedata.observe(this) {it ->
// here breakpoint
}

but common way work fine
.observe(lifecycleOwner, Observer { result ->
// result is non-null and always true
})

[Kadanza]

point 4 :
some device have this error (with old api Android)

Nexus 6p - Android 8.1 doesn't have this mistake

[henrytao-me]

Hi @Kadanza, I missed your original message. Thanks for reaching out. Hopefully, I can address some of your questions below:

1. what improvement has version 3.0.0?
2. why need MutableLiveDataKtx instead MutableLiveData?

As listed in the README, v3 focuses on Kotlin friendly, preserve immutability, and extensibility. For instance, you still can set null value for a non-null LiveData which can cause NPE at runtime. Compiler should be able to prevent it.

// Allow to set null value to LiveData
val liveData = MutableLiveData<Boolean>()
liveData.value = null

// LiveDataKtx doesn't allow to null value
val liveData = MutableLiveDataKtx<Boolean>()
liveData.value = null // doesn't allow

// Set nullable in LiveDataKtx
val liveData = MutableLiveDataKtx<Boolean?>()
liveData.value = null

3. In version 2.0 we has great extension observe without Observer

There is tradeoffs for the approach. Kotlin lambda generates different object down to Java layer which makes harder to remove the observer later on.

4. In version 2.0 I has unpleasant bug in android studio

I haven't encountered this issue. I can take a look later.

[Kadanza]

point 3 : are you not recommend use version 2 because of problem with memory?

I use version 2 widely

[henrytao-me]

If you use v2.0.2, removeObserver should work properly as we had a fix for it https://github.com/Shopify/livedata-ktx/releases/tag/v2.0.2.

So, migrating to v3 is an optional.

[henrytao-me]

Let us know if you have any other concerns. I will close this issue for now. Feel free to reopen if needed.