Use android.R.attr.listDivider as the default Drawable

[fondesa]

Related to #41

[fondesa]

Just released the version 3.2.0 which uses android:listDivider by default to get the divider's Drawable.

[AndroidDeveloperLB]

And in code, like this:

RecyclerViewDivider.with(context).addTo(this) 

Meaning no need for this:

fun RecyclerView.setDefaultDividers() {
    val context = this.context
    context.obtainStyledAttributes(intArrayOf(android.R.attr.listDivider)).use { typedArray ->
        typedArray.getDrawable(0)
                ?.let { RecyclerViewDivider.with(context).drawable(it).hideLastDivider().build().addTo(this) }
    }
}

?

[fondesa]

The RecyclerViewDivider API is deprecated in favour of the new DividerBuilder API.

You can replace this whole function:

fun RecyclerView.setDefaultDividers() {
    val context = this.context
    context.obtainStyledAttributes(intArrayOf(android.R.attr.listDivider)).use { typedArray ->
        typedArray.getDrawable(0)
                ?.let { RecyclerViewDivider.with(context).drawable(it).hideLastDivider().build().addTo(this) }
    }
}

With just:

recyclerView.addDivider()

Because:

• now the default divider reads the value of android.R.attr.listDivider
• now the default divider hides the last divider by default

[AndroidDeveloperLB]

Seems not working for me on dark theme for some reason, while working fine on normal theme.

Can you test, or should I try on POC ?

At least using the old method I've made seems to still work as before.

[fondesa]

I'll try it soon, thanks!

[AndroidDeveloperLB]

Please let me know about it.

[fondesa]

@AndroidDeveloperLB I reproduced it and I found the line of code which causes it.
It's the following one:

DrawableCompat.setTintList(wrappedDrawable, null)

This line is necessary to reset the tint of the single divider to avoid the tint color to propagate to the other dividers.

Now I have to understand why it changes the Drawable on night theme.

[fondesa]

It's very similar to this issue on Android: https://issuetracker.google.com/issues/141678225
The problem is that the default divider color on API > 21 is #ffdadce0 on light theme and #85ffffff on dark theme.

The problem is tinting a GradientDrawable with a color which isn't fully opaque, that's why it fails only on dark theme.

I'll replace the call to setTintList with a ColorFilter if I can't succeed to make it working in the standard way.

[AndroidDeveloperLB]

OK for now I will use the previous method. It still works fine.

[AndroidDeveloperLB]

Is there a shorter workaround than using what I wrote, BTW?

[fondesa]

You can probably change the value of android:listDivider to a plain color with those values that I wrote above (the one in the Android material version). But I'll release a fix pretty soon so I don't think it's worth

[AndroidDeveloperLB]

I need in code. Anyway, please let me know when you fix this.

[fondesa]

Yes, I'll notify you for any update

[AndroidDeveloperLB]

Thank you. If you with, this is my app that uses this repository.

[fondesa]

@AndroidDeveloperLB Released the version 3.2.1 containing the fix. Can you let me know if addDivider() works for you now?

[AndroidDeveloperLB]

I think now it's indeed fixed and working well.
Thank you.

BTW, why add extension function?
This isn't something that's common for libraries. Usually it's reserved for the main project itself, not for libraries, unless it's a very core function (kotlin basic classes, for example).

[fondesa]

Nice, to hear.

I added the extension function to create a divider using the shortest syntax and made it more accessible for Kotlin users of this library since creating the divider is the core API of this library (other APIs like RecyclerViewDividerLog which aren't related to the core one, are still expressed without extension functions). I did it also following bigger repositories written in Kotlin like Coil.

I honestly think it's more a matter of personal taste than something objective in general.

(I'm closing this issue since the bug was fixed)

[AndroidDeveloperLB]

OK your choice. Are there more extension functions on the library now?

[fondesa]

Since the version 3.2.0 (the one with new APIs) there are these 4 extensions, all 4 on RecyclerView:

• addDivider()
• dividerBuilder()
• addStaggeredDivider()
• staggeredDividerBuilder()

[AndroidDeveloperLB]

ok thanks.