Can I make the contacts in my account read-only?

[AutoImport-wtttc]

Hi！I'm using DAVDroid,and thanks for your work it works pretty good with owncloud .But i want to make the contacts in my account read-only,so i won't changed the contacts data accidentally on Android devices.Some apps like wechat work like this.

I've tried in sync-contacts.xml like:

<sync-adapter xmlns:android="http://schemas.android.com/apk/res/android"
    android:accountType="bitfire.at.davdroid"
    android:contentAuthority="com.android.contacts"
    android:allowParallelSyncs="false"
    android:supportsUploading="false"
    android:isAlwaysSyncable="true"
    android:userVisible="false" />

and it seems useless.

Thanks.

[AutoImport-wtttc]

see: http://stackoverflow.com/questions/6549624/android-make-a-contact-not-editable-on-the-phone

[rfc2822]

supportsUploading is only used to decide whether a sync process should be started on local data changes (see AbstractThreadedSyncAdapter docs). However, the sync process itself (as soon as it started) is always two-way by design.