How do I get a list of contacts in a more advanced way?

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How do I get a list of contacts in a more advanced way?

This library provides the Query API that allows you to get a list of Contacts matching a specific search criteria. All RawContacts of matching Contacts are included in the resulting Contact instances.

This provides a great deal of granularity and customizations when providing matching criteria via the where function.

An instance of the Query API is obtained by,

val query = Contacts(context).query()

For a broader, and more native Contacts app like query, use the BroadQuery API. For more info, read How do I get a list of contacts in the simplest way?

If you want to query Data directly instead of Contacts, read How do I get a list of specific data kinds?

If you want to get the device owner Contact Profile, read How do I get the device owner Contact profile?

An advanced query

To retrieve the first 5 contacts (including only the contact id, display name, and phone numbers in the results) ordered by display name in descending order, matching ALL of these rules;

val contacts = Contacts(context)
    .query()
    .where {
        (Name.GivenName startsWith "leo") and
        (Email.Address { endsWith("gmail.com") or endsWith("hotmail.com") }) and
        (Address.Country equalToIgnoreCase "us") and
        (Event { (Date lessThan Date().toWhereString()) and (Type equalTo EventEntity.Type.BIRTHDAY) }) and
        (Contact.Options.Starred equalTo true) and
        (Nickname.Name equalTo "DarEdEvil") and
        (Organization.Company `in` listOf("facebook", "FB")) and
        (Note.Note.isNotNullOrEmpty())
    }
    .accounts(
        Account("john.doe@gmail.com", "com.google"),
        Account("john.doe@myspace.com", "com.myspace"),
    )
    .include { setOf(
        Contact.Id,
        Contact.DisplayNamePrimary,
        Phone.Number
    ) }
    .orderBy(ContactsFields.DisplayNamePrimary.desc())
    .offset(0)
    .limit(5)
    .find()

A basic query

This query API may also be used to make basic, simpler queries.

To get all contacts ordered by the primary display name,

val contacts = Contacts(context)
    .query()
    .orderBy(ContactsFields.DisplayNamePrimary.asc())
    .find()

To get all contacts with a phone number AND email,

val contacts = Contacts(context)
    .query()
    ...
    .where{ Phone.Number.isNotNullOrEmpty() and Email.Address.isNotNullOrEmpty() }
    .find()

Note that phone numbers are a special case because the Contacts Provider keeps track of the existence of a phone number for any given contact. Use Contact.HasPhoneNumber equalTo true instead for a more optimized query.

To get a list of contacts with the given IDs,

val contacts = Contacts(context)
    .query()
    ...
    .where { Contact.Id `in` contactIds }
    .find()

Including blank contacts

The API allows you to specify if you want to include blank contacts or not,

.includeBlanks(true|false)

For more info, read How do I learn more about “blank” contacts?

Specifying Accounts

To limit the search to only those contacts associated with one of the given accounts,

.accounts(accounts)

For example, to limit the search to contacts belonging to only one account,

.accounts(Account("john.doe@gmail.com", "com.google"))

For more info, read How do I query for Accounts?

The Contacts returned may still contain RawContacts / data that belongs to other accounts not specified in the given accounts because Contacts may be made up of more than one RawContact from different Accounts. This is the same behavior as the native Contacts app.

If no accounts are specified (this function is not called or called with no Accounts), then all RawContacts of Contacts are included in the search.

A null Account may be provided here, which results in RawContacts with no associated Account to be included in the search. RawContacts without an associated account are considered local contacts or device-only contacts, which are not synced.

For more info, read How do I learn more about “local” (device-only) contacts?

Note that this may affect performance. This may require one or more additional queries, internally performed in this function, which increases the time required for the search. Therefore, you should only specify this if you actually need it.

Including only specific data

To include only the given set of fields (data) in each of the matching contacts,

.include(fields)

For example, to only include email and name fields,

.include { Email.all + Name.all }

For more info, read How do I include only the data that I want?

Specifying Groups

To limit the search to only those RawContacts associated with at least one of the given groups,

.where { GroupMembership.GroupId `in` groups.mapNotNull { it.id } }

For more info, read How do I retrieve groups?

Contacts returned may still contain RawContacts / data that belongs to other groups not specified in the given groups because Contacts may be made up of more than one RawContact from different Groups. This is the same behavior as the native Contacts app.

If no groups are specified, then all RawContacts of Contacts are included in the search.

Note that this may affect performance. This may require one or more additional queries, internally performed in this function, which increases the time required for the search. Therefore, you should only specify this if you actually need it.

Ordering

To order resulting Contacts using one or more fields,

.orderBy(fieldOrder)

For example, to order contacts by favorite/starred status such that favorite/starred contacts appear first in the list AND order by display name primary in ascending order (from a to z ignoring case),

.orderBy(
    ContactsFields.Options.Starred.desc(),
    ContactsFields.DisplayNamePrimary.asc()
)

String comparisons ignores case by default. Each orderBys provides ignoreCase as an optional parameter.

Use ContactsFields to construct the orderBys.

If you need to sort a collection of Contacts outside of a database query using any field (in addition to ContactsFields), use contacts.core.util.ContactsComparator. For more info, read How do I use some miscellaneous extension functions to make my life easier?

Limiting and offsetting

To limit the amount of contacts returned and/or offset (skip) a specified number of contacts,

.limit(limit)
.offset(offset)

For example, to only get a maximum 20 contacts, skipping the first 20,

.limit(20)
.offset(20)

This is useful for pagination =)

Note that it is recommended to limit the number of contacts when querying to increase performance and decrease memory cost.

Executing the query

To execute the query,

.find()

Cancelling the query

To cancel a query amid execution,

.find { returnTrueIfQueryShouldBeCancelled() }

The find function optionally takes in a function that, if it returns true, will cancel query processing as soon as possible. The function is called numerous times during query processing to check if processing should stop or continue. This gives you the option to cancel the query.

This is useful when used in multi-threaded environments. One scenario where this would be frequently used is when performing queries as the user types a search text. You are able to cancel the current query when the user enters new text.

For example, to automatically cancel the query inside a Kotlin coroutine when the coroutine is cancelled,

launch {
    withContext(coroutineContext) {
        val contacts = query.find { !isActive }
    }
}

Performing the query asynchronously

Queries are executed when the find function is invoked. The work is done in the same thread as the call-site. This may result in a choppy UI.

To perform the work in a different thread, use the Kotlin coroutine extensions provided in the async module. For more info, read How do I use the async module to simplify executing work outside of the UI thread using coroutines?

You may, of course, use other multi-threading libraries or just do it yourself =)

Extensions for Kotlin Flow and RxJava are also in the v1 roadmap, which includes APIs for listening to Contacts database changes.

Performing the query with permission

Queries require the android.permission.READ_CONTACTS permission. If not granted, the query will do nothing and return an empty list.

To perform the query with permission, use the extensions provided in the permissions module. For more info, read How do I use the permissions module to simplify permission handling using coroutines?

You may, of course, use other permission handling libraries or just do it yourself =)

Custom data support

The Query API supports custom data. For more info, read How do I use query APIs to get custom data?

Using the where function to specify matching criteria

Use the contacts.core.Fields combined with the extensions from contacts.core.Where to form WHERE clauses.

This howto page will not provide a tutorial on database where clauses. It assumes that you know the basics. If you don’t know the basics, then search for sqlite where clause.

For example, to get all contacts with a phone number AND email,

val contacts = Contacts(context)
    .query()
    ...
    .where { Phone.Number.isNotNullOrEmpty() and Email.Address.isNotNullOrEmpty() }
    .find()

To get a list of contacts with the given IDs,

val contacts = Contacts(context)
    .query()
    ...
    .where { Contact.Id `in` contactIds }
    .find()

Limitations

This library only provides basic WHERE functions. It does not cover the entirety of SQLite, though the community may add more over time <3

Furthermore, this library is constrained by rules and limitations set by the Contacts Provider and the behavior of the native Contacts app. One such rule/limitation has resulted in this library not providing WHERE functions such as isNull or isNullOrEmpty to prevent making misleading queries.

Removing a piece of existing data results in the deletion of the row in the Data table if that row no longer contains any meaningful data. This is the behavior of the native Contacts app. Therefore, querying for null fields is not possible. For example, there may be no Data rows that exist where the email address is null. Thus, a query to search for all contacts with no email addresses may return 0 contacts even if there are some contacts that do not have at least one email address.

If you want to match contacts that has no particular type of data, you will have to make two queries. One to get contacts that have that particular type of data and another to get contacts that were not part of the first query results. For example,

val contactsWithEmails = query
    .include(Fields.Contact.Id)
    .where { Email.Address.isNotNullOrEmpty() }
    .find()

val contactIdsWithEmails = contactsWithEmails.mapNotNull { it.id }
val contactsWithoutEmails = query
    .where { Contact.Id notIn contactIdsWithEmails }
    .find()

There is a special case with phone numbers. The ContactsContract provides a field that is true if the contact has at least one phone number; Fields.Contact.HasPhoneNumber. The phone number is the only kind of data that the ContactsContract provides with an indexed value such as this. The ContactsContract does NOT provide things like “hasEmail”, “hasWebsite”, etc. Regardless, this library provide functions to match contacts that “has at least one instance of a kind of data”. The HasPhoneNumber field is not necessary to get contacts that have a phone number. However, this does provide an easy way to get contacts that have no phone numbers without having to make two queries. For example,

val contactsWithNoPhoneNumbers = query
    .where { Contact.HasPhoneNumber notEqualTo true }
    .find()

Blank Contacts and the where function

The where function is only used to query the Data table. Some contacts do not have any Data table rows. However, this library exposes some fields that belong to other tables, accessible via the Data table with joins;

Using these fields in the where clause does not have any effect in matching blank Contacts or blank RawContacts simply because they have no Data rows containing these joined fields.

For more info, read How do I learn more about “blank” contacts?