Make Google login a suspend fun which waits for auth completion

app/src/main/java/de/mm20/launcher2/fragment/PreferencesSearchFragment.kt

@@ -153,8 +153,10 @@ class PreferencesSearchFragment : PreferenceFragmentCompat() {
     }
 
     private fun googleLogin() {
+        lifecycleScope.launch {
             GoogleApiHelper.getInstance(requireContext()).login(requireActivity())
         }
+    }
 
     private fun setSettingsScreen(fragment: Fragment) {
         parentFragmentManager.beginTransaction()

app/src/main/java/de/mm20/launcher2/fragment/PreferencesServicesFragment.kt

@@ -47,7 +47,9 @@ class PreferencesServicesFragment : PreferenceFragmentCompat() {
                 setTitle(R.string.preference_google_signin)
                 setSummary(R.string.preference_google_signin_summary)
                 setOnPreferenceClickListener {
+                    lifecycleScope.launch {
                         googleApiHelper.login(requireActivity())
+                    }
                     true
                 }
             }

g-services/src/main/java/de/mm20/launcher2/gservices/GoogleApiHelper.kt

@@ -4,6 +4,7 @@ import android.app.Activity
 import android.content.Context
 import android.content.Intent
 import android.net.Uri
+import android.util.Log
 import androidx.browser.customtabs.*
 import androidx.core.content.edit
 import com.google.api.client.auth.oauth2.Credential
@@ -17,6 +18,7 @@ import com.google.api.services.drive.Drive
 import com.google.api.services.oauth2.Oauth2
 import de.mm20.launcher2.crashreporter.CrashReporter
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.suspendCancellableCoroutine
 import kotlinx.coroutines.withContext
 import java.io.IOException
 
@@ -119,9 +121,12 @@ class GoogleApiHelper private constructor(private val context: Context) {
             .build()
     }
 
-    fun login(activity: Activity) {
+    private var callback: (() -> Unit)? = null
+
+    suspend fun login(activity: Activity) {
         val authFlow = getAuthFlow() ?: return
 
+        suspendCancellableCoroutine<Unit> {
             val url = authFlow
                 .newAuthorizationUrl()
                 .setRedirectUri(getRedirectUri())
@@ -139,9 +144,18 @@ class GoogleApiHelper private constructor(private val context: Context) {
                 .build()
 
             callingActivity = activity.javaClass
+            callback = {
+                it.resumeWith(Result.success(Unit))
+            }
+            it.invokeOnCancellation {
+                callback = null
+                Log.d("MM20", "Google Signin has been canceled")
+            }
 
             customTabsIntent.intent.flags = Intent.FLAG_ACTIVITY_NO_HISTORY
             customTabsIntent.launchUrl(activity, Uri.parse(url))
+
+        }
     }
 
     suspend fun finishAuthFlow(activity: Activity, code: String) {
@@ -168,6 +182,7 @@ class GoogleApiHelper private constructor(private val context: Context) {
         callingActivity = null
         intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP or Intent.FLAG_ACTIVITY_SINGLE_TOP)
         activity.startActivity(intent)
+        callback?.invoke()
     }
 
     private suspend fun loadAccountName(): String? {