Show a snack if missing permissions.

A lot of people don't grant etesync the appropriate permissions
and then complain it doesn't work. Hopefully this will fix this
point of failure.

app/src/main/java/com/etesync/syncadapter/ui/AccountsActivity.kt

@@ -12,6 +12,7 @@ import android.content.ContentResolver
 import android.content.ContentResolver.SYNC_OBSERVER_TYPE_SETTINGS
 import android.content.Intent
 import android.content.SyncStatusObserver
+import android.content.pm.PackageManager
 import android.os.Bundle
 import android.view.Gravity
 import android.view.MenuItem
@@ -132,6 +133,26 @@ class AccountsActivity : BaseActivity(), NavigationView.OnNavigationItemSelected
         return true
     }
 
+    override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<String>, grantResults: IntArray) {
+        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
+        val denied = HashMap<String, Boolean>()
+        for (permission in permissions.withIndex()) {
+            val status = grantResults[permission.index]
+            if (status != PackageManager.PERMISSION_GRANTED) {
+                val key = permission.value.substringAfterLast('_')
+                if (key != "TASKS") {
+                    // We don't want to show it for tasks
+                    denied[key] = true
+                }
+            }
+        }
+
+        if (denied.size > 0) {
+            val deniedString = denied.keys.joinToString(", ")
+            Snackbar.make(findViewById(R.id.coordinator), getString(R.string.accounts_missing_permissions, deniedString), Snackbar.LENGTH_INDEFINITE).show()
+        }
+    }
+
     companion object {
         val HINT_ACCOUNT_ADD = "AddAccount"
     }

app/src/main/res/values/strings.xml

@@ -81,6 +81,7 @@
     <string name="accounts_global_sync_disabled">System-wide automatic synchronization is disabled</string>
     <string name="accounts_global_sync_enable">Enable</string>
     <string name="accounts_showcase_add">You need to add an account in order to use EteSync. Click here to add one...</string>
+    <string name="accounts_missing_permissions">Missing permissions: %s</string>
 
     <!-- AccountUpdateService -->