Custom Tabs warm up

CustomTabUtil.kt

package net.swiftzer.metroride.app.customtab

import android.content.ActivityNotFoundException
import android.content.ComponentName
import android.content.Context
import android.content.Intent
import android.content.pm.PackageManager
import android.net.Uri
import androidx.browser.customtabs.CustomTabsCallback
import androidx.browser.customtabs.CustomTabsClient
import androidx.browser.customtabs.CustomTabsIntent
import androidx.browser.customtabs.CustomTabsServiceConnection
import androidx.browser.customtabs.CustomTabsSession
import kotlinx.coroutines.channels.awaitClose
import kotlinx.coroutines.flow.callbackFlow
import timber.log.Timber

private const val STABLE_PACKAGE = "com.android.chrome"
private const val BETA_PACKAGE = "com.chrome.beta"
private const val DEV_PACKAGE = "com.chrome.dev"
private const val LOCAL_PACKAGE = "com.google.android.apps.chrome"

/**
 * Goes through all apps that handle VIEW intents and have a warmup service. Picks
 * the one chosen by the user if there is one, otherwise makes a best effort to return a
 * valid package name.
 *
 * This is **not** threadsafe.
 *
 * @param context [Context] to use for accessing [PackageManager].
 * @return The package name recommended to use for connecting to custom tabs related components.
 */
fun getCustomTabPackageNameToUse(context: Context): String? {
    // Get default VIEW intent handler.
    val activityIntent = Intent(Intent.ACTION_VIEW, Uri.parse("https://example.com"))
    val defaultViewHandlerInfo = context.packageManager.resolveActivity(activityIntent, 0)
    val defaultViewHandlerPackageName = defaultViewHandlerInfo?.activityInfo?.packageName

    // Get all apps that can handle VIEW intents.
    val packagesSupportingCustomTabs =
        context.packageManager.queryIntentActivities(activityIntent, 0)
            .asSequence()
            .map {
                val serviceIntent = Intent().apply {
                    action = "android.support.customtabs.action.CustomTabsService"
                    `package` = it.activityInfo.packageName
                }
                if (context.packageManager.resolveService(serviceIntent, 0) != null) {
                    it.activityInfo.packageName
                } else {
                    ""
                }
            }
            .filter { it.isNotBlank() }
            .toList()

    // Now packagesSupportingCustomTabs contains all apps that can handle both VIEW intents
    // and service calls.
    return when {
        packagesSupportingCustomTabs.isEmpty() -> null
        packagesSupportingCustomTabs.size == 1 -> packagesSupportingCustomTabs.first()
        !defaultViewHandlerPackageName.isNullOrBlank() &&
            !hasSpecializedHandlerIntents(context, activityIntent) &&
            packagesSupportingCustomTabs.contains(defaultViewHandlerPackageName) -> {
            defaultViewHandlerPackageName
        }

        packagesSupportingCustomTabs.contains(STABLE_PACKAGE) -> STABLE_PACKAGE
        packagesSupportingCustomTabs.contains(BETA_PACKAGE) -> BETA_PACKAGE
        packagesSupportingCustomTabs.contains(DEV_PACKAGE) -> DEV_PACKAGE
        packagesSupportingCustomTabs.contains(LOCAL_PACKAGE) -> LOCAL_PACKAGE
        else -> null
    }
}

/**
 * Used to check whether there is a specialized handler for a given intent.
 *
 * @param intent The intent to check with.
 * @return Whether there is a specialized handler for the given intent.
 */
private fun hasSpecializedHandlerIntents(context: Context, intent: Intent): Boolean {
    try {
        val handlers =
            context.packageManager.queryIntentActivities(intent, PackageManager.GET_RESOLVED_FILTER)
        if (handlers.isEmpty()) return false
        for (resolveInfo in handlers) {
            val filter = resolveInfo.filter ?: continue
            if (filter.countDataAuthorities() == 0 || filter.countDataPaths() == 0) continue
            if (resolveInfo.activityInfo == null) continue
            return true
        }
    } catch (e: RuntimeException) {
        Timber.e(e, "hasSpecializedHandlerIntents: runtime error")
    }
    return false
}

fun connectAndBindCustomTabsService(context: Context) = callbackFlow {
    trySend(null)

    var isCustomTabsServiceBindingSuccess = false
    val connection = object : CustomTabsServiceConnection() {
        override fun onCustomTabsServiceConnected(
            name: ComponentName,
            client: CustomTabsClient,
        ) {
            client.warmup(0)
            val session = client.newSession(CustomTabsCallback())
            trySend(session)
        }

        override fun onServiceDisconnected(name: ComponentName?) {
            // no-op
        }
    }

    val packageName = getCustomTabPackageNameToUse(context)
    if (packageName != null) {
        isCustomTabsServiceBindingSuccess =
            CustomTabsClient.bindCustomTabsService(context, packageName, connection)
    }

    awaitClose {
        if (isCustomTabsServiceBindingSuccess) {
            context.unbindService(connection)
        }
    }
}

suspend fun launchCustomTab(
    context: Context,
    customTabsSession: CustomTabsSession?,
    uri: Uri,
    onMissingDefaultBrowser: suspend () -> Unit,
) {
    when {
        getCustomTabPackageNameToUse(context) != null -> {
            val customTabsIntent = CustomTabsIntent.Builder(customTabsSession)
                .setShowTitle(true)
                .build()
            customTabsIntent.launchUrl(context, uri)
        }

        else -> try {
            context.startActivity(Intent(Intent.ACTION_VIEW, uri))
        } catch (e: ActivityNotFoundException) {
            onMissingDefaultBrowser()
        }
    }
}

Example.kt

coroutineScope.launch {
    val customTabSession = connectAndBindCustomTabsService(context)
        .flowWithLifecycle(
            lifecycleOwner.lifecycle,
            Lifecycle.State.STARTED,
        )
        .firstOrNull()
    launchCustomTab(
        context,
        customTabSession,
        "https://support.google.com/googleplay/answer/9037938".toUri(),
    ) {
        scaffoldState.snackbarHostState.showSnackbar(activityNotFoundText)
    }
}