I found it rather difficult to us `compose-wear` w...

# compose-wear

[Yingding Wang]

I found it rather difficult to us compose-wear with an AppCompactActivity on Wear OS, if i want to migrate to wear compose along side my view system code.
The following steps are necessary:
1. the view code need to use Theme.AppCompat.DayNight.NoActionBar from MDC lib com.google.android.material:material
2. use the AppCompatTheme Adaptor from the Accompanist com.google.accompanist:accompanist-appcompat-theme to copy over the AppCompat Theme to a MaterialTheme composable
3. Add wear compose dependencies, and also horologist dependencies
I wish there is a codelab for this 🙂

I made an example project to demo this possibility that I can also migrate to compose-wear starting with new features along side view system code (https://github.com/yingding/wear-os-examples/tree/main/Wear3KtxPagerExample), would love to hear your thoughts on this.

[yschimke]

Thanks for the sample project, I'll take a look. I'm more familiar with the interop options, from a more technical than design perspective. ComposeView, AndroidView, GoogleMaps (before the compose wrapper).

[yschimke]

A few comments - I think you should avoid AppCompatTheme, the MaterialTheme it brings in, is not the one that is compatible with Composer for Wear OS's MaterialTheme.

[yschimke]

androidx.compose.material.MaterialTheme vs androidx.wear.compose.material.MaterialTheme.

[yschimke]

What is the structure of your app? Is it a single Activity? Using Wear Navigation? Or multiple Activities, one of which is going to use Compose for now?

[yschimke]

BTW The training materials talk about these replacements for navigation and material. https://developer.android.com/training/wearables/compose#different

[yschimke]

What are the styles you need from Theme.AppCompat.DayNight.NoActionBar in com.google.android.material:material, over taking one of the app compat themes and customising it for your existing Compose views? Do you existing Wear Views use some Material Features from that theme?

[yschimke]

Actually that one is from AppCompat, not from Material. So I don't see the problem.

[Yingding Wang]

@yschimke Thanks also for so many great comments and feedbacks. My current wear os app is a multi-activities wear os app, which has a MainActivity as FragmentActivity uses WearableNavigationDrawerView and WearableActionDrawerView. I haven’t used Wear Navigation yet. There is also an Onboarding Activity of AppCompatActivity using an old GridViewPager with wearable.view.CardFragment.

I am currently replacing the GridViewPager with compose-wear and ideally Horologist PagerScreen or Accompanist Pager layouts

I have to admit, that I am also not a theme specialist, The different theme and also AppCompatActivity came from the different third-part libs I used. Some time I need FragmentActivity, sometime AppCompatActivity. For the AppCompatActivity, i am force to use the old theme.

I know the solution using AppCompatTheme Adaptor is not ideal, but it helps me to start replacing the view code with compose code. Otherwise, i have to rewrite the old features with Material Theme.

I also used some Material Theme in Dialog, which is also quite hacky.

[yschimke]

You should really avoid the non Wear Material Theme. Can get confusing with things like Text. You want to be using androidx.wear.compose.material.Text.

[yschimke]

I haven't gone through this process for real with a Wear Views app, and then migrating to Compose.

[yschimke]

The pre-canned advice would be
a) structure your app following modern guidance so it's easy to migrate, separate UI layers, data layers, use ViewModel.

[yschimke]

b) Change a whole screen/activity at a time. Could this new activity use Component Activity, and you as a one off copy the View theme values into a MaterialTheme?

[yschimke]

What breaks (the third party libs) in the screen you are trying to use if you don't use FragmentActivity or AppCompatActivity? Is it a public lib?

[Yingding Wang]

@yschimke Thanks, I will definitely try to update to a Wear Material Theme first. Will the compose also work with FragmentActivity which is needed for AmbientModeSupport. For the non-ambient activity, i can try to use ComponentActivity instead.

[yschimke]

I'm not sure, but the samples suggests it needs FragmentActivity https://github.com/android/wear-os-samples/blob/main/AlwaysOnKotlin/compose/src/main/java/com/example/android/wearable/wear/alwayson/MainActivity.kt#L82

[yschimke]

From that codelab - I think it's mostly all still relevant on wear with two exceptions https://developer.android.com/codelabs/jetpack-compose-migration

[yschimke]

1. We don't have an option for the Theme Adapter, while apparently mobile compose has 2 (Accompanist + Material),
2. We would generally advise against a wear screen being a patchwork of components. I think device sizes plays to our advantage here, in that it's easier to migrate a Wear screen, hopefully focused on a single feature, rather than a mobile screen that might have multiple features and reused menus etc.

[Yingding Wang]

@yschimke You are right. I found a better way to migrate my view system multi-activity wear os app to compose-wear without the AppTheme Adapter.

1. create an additional theme in values/styles.xml

<style name="composeWearAppTheme" parent="@android:style/Theme.DeviceDefault" ></style>

2. Apply the migration theme for each activity to migrate in AndroidManifest.xml

<activity
            android:name=".migrateToComposeWearActivity"
            android:label="ComponentActivity"
            android:theme="@style/composeWearAppTheme"
            android:exported="false"/>

3. Adopt style to theme/Color.kt , theme/Theme.kt ,theme/Type.kt manually and gradually activity by activity

With this approach I can keep my old Theme.AppCompat and also use Wear Material Theme separately and don’t need to mix them.

[yschimke]

That's good to here. And thanks for working through it and posting here. Helps us with examples we can point to.

[yschimke]

As you migrate please let us know about any tips you find helpful, or alternatively if anything is harder than with views, please let us know.