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ContactsThe Contacts API enables a client to request contact data from local or remote backends. This is part of the Qt Mobility Project. NamespaceThe QtMobility APIs are placed into the QtMobility namespace. This is done to facilitate the future migration of Mobility APIs into Qt. See the Quickstart guide for an example on how the namespace impacts on application development. IntroductionThe Contacts API provides clients with the ability to access contact data in a platform-independent and datastore-agnostic manner. This is achieved by defining generic personal information data abstractions which can sufficiently describe contact data stored on any platform. Due to the cross-platform nature of the API, and the ability for developers to write platform-independent implementations of a QContactManager which may unify one or more platform-specific contact backends, it is intended that the semantics and quirks of the underlying datastores on any platform may be entirely opaque from the perspective of Qt-based, cross-platform client applications. OverviewThe QtMobility APIs are placed into the QtMobility namespace. This is done to facilitate the future migration of Mobility APIs into Qt. See the Quickstart guide for an example on how the namespace impacts on application development. Contact information is stored in datastores whose functionality is exposed via a manager. The Contacts API models a contact as a collection of distinct details. Each detail conforms to a particular definition (or template), which may be extensible or otherwise modifiable by clients. Individual contacts may be related to one other, and these relationships are stored separately from contacts themselves and may be manipulated directly by clients. Contact, detail definition, and relationship information may all be retrieved, modified or deleted by clients using either synchronous or asynchronous API. Client-Facing APIThe client-facing API allows retrieval, modification and deletion of contacts, detail definitions and relationships, and access to manager meta data and capability reporting. Container ClassesContact information is stored in container (value) classes. These classes are not derived from QObject, and hence can be used in lists, do not have parents, do not emit signals, and so on. They represent data which may be manipulated and retrieved from a manager. ContactA contact is the digital representation of a person, group or entity, which is stored in a platform-specific manner. Information pertaining to a single contact may be located across several different datastores, and each datum (or detail) may or may not pertain to a particular context in which that information is valid. A contact may include semantically identical pieces of information that are relevant in different contexts. For example, a contact may have a phone number that is relevant to their "home" context, and another phone number that is relevant to their "work" context. It can be seen that the context of information defines its validity to the user, depending on the context of usage; and as such, the sum of information in a given context can be considered equivalent to a "contextual identity". This allows great flexibility when consolidating data from various sources into a single, cohesive contact. Each contact stored in a manager is identified by an id which consists of a manager identifier (URI) and the manager-local id which is used to identify the contact in that manager. Note that a contact stored in one manager may have the same local id as a different contact stored in another manager; please see the QContactId documentation for more information. DetailA detail is a single, cohesive unit of information that is stored in a contact. As explained previously, it is valid for a particular context or set of contexts, and conforms to a particular definition. A detail may have specific metadata associated with it, such as its sub-type, context, and arbitrary, user-defined metadata, as well as access constraints which may apply to the the detail (such as read-only, irremovable, etc). There are a number of common details defined in the API which are intended for use by clients, as listed here. Detail DefinitionEach detail stored in a contact has defined semantics of usage and storage. The Qt Contacts API allows per-datastore contact detail definitions, allowing a manager to provide clients with this information on demand, and allowing third-party developers to register detail definitions for use by clients. A detail definition includes the fields (and value-types of those fields) which make up the detail, and per-contact uniqueness constraints on details of the definition. Most clients can safely ignore this class entirely, since they will most likely want to use the predefined details listed here. In some cases, however, a manager will not support all of the fields of a particular predefined detail leaf class; in that case, it may be necessary for the client to inspect the supported detail definition for that leaf class and modify its behavior accordingly (for example, if the CustomLabel field of the QContactName leaf detail is not supported in a particular manager). RelationshipsContacts may participate in relationships with other contacts. The details of any such relationship is stored by the manager which contains the contact. There are several standard relationship types supported by the default schema, and arbitrary relationship types are also allowed if the manager supports that feature. One important relationship is that of group membership; membership of a contact in a group can be modeled as that group contact participating in a HasMember relationship with the contact. ManagerAccess to contacts is provided by implementations of the Qt Contacts manager API. A manager provides access to zero or more platform-specific datastores. Each datastore may support different capabilities (for example, the ability to store certain datatypes, the ability to natively filter on different details or details of different definitions, the provision of locking mechanisms, the provision of changelog information, etc) which are reported by the manager on request. The manager therefore provides access to detail definitions, contacts, and relationships stored in different datastores, in a platform and datastore independent manner. Meta Data APIThe API offered by the QContactManager exposes functionality which is implemented by plugins. These plugins may be platform specific, and may be provided by Nokia or by third party developers. As described above, each plugin will have different capabilities and implement the functionality exposed by the Contacts API to a different degree. The QContactManager class provides a static function QContactManager::availableManagers() which allows clients of the API to determine (at run time) which plugins (managers) are available for use. Clients of the API also need to be able to determine (at run time) what the capabilities of a given plugin (contact manager) are. The QContactManager class provides API to query the capabilities of a given manager with the following synchronous functions:
A given manager is identified by its URI. The URI consists of the manager's name, any relevant parameters which were used during instantiation of the manager, and the version of the manager. While the name of the manager identifies the plugin which provides the functionality, you cannot guarantee that the data available through one manager will be available through another with the same name (for example, if one parameter tells the plugin to store and retrieve contact information from a particular online service or local file). The synchronous API offered to allow run-time querying of a manager's metadata includes:
The functionality that the above functions provide is only available through synchronous API. Asynchronous APIThe asynchronous API provides a way to access or modify the contact information managed by a particular backend via non-blocking, asynchronous requests. It is recommended for most applications that the asynchronous API be used where possible. The asynchronous API is offered through various classes derived from the QContactAbstractRequest class, including QContactLocalIdFetchRequest, QContactFetchRequest, QContactSaveRequest, QContactRemoveRequest, QContactDetailDefinitionFetchRequest, QContactDetailDefinitionSaveRequest, QContactDetailDefinitionRemoveRequest, QContactRelationshipFetchRequest, QContactRelationshipSaveRequest, and QContactRelationshipRemoveRequest. The asynchronous API allows manipulation of contacts, contact relationships, and schema definitions, but does not provide manager capability or meta data information reporting. For more detailed documentation on the asynchronous API, see the Contacts Asynchronous API. Synchronous APIThe synchronous API provides the simplest way to access or modify the contact information managed by a particular backend. It has the disadvantage that calls block the current thread of execution until completion and is therefore most suitable only for applications which interact with local, high-speed datastores, or for applications which do not require a responsive user interface. The synchronous API is offered through the QContactManager class, and includes manipulation of contacts, contact relationships, and schema definitions. As previously described, the meta data reporting and manipulation functions are also provided via synchronous API only. For more detailed documentation on the synchronous API, see the Contacts Synchronous API. ActionsClients can perform actions on contacts which support them. Actions are things like "Send Email" or "Dial", and can be provided from various sources including Qt Plugins or the Qt Mobility Service Framework. Every action implementation is uniquely identified by a combination of its name, the name of the service which provided the implementation, and the version of the implementation. These pieces of data may be encapsulated in a QContactActionDescriptor which can be used to retrieve an instance of the implementation from a QContactActionFactory. Different actions will allow (or require) different parameters to invocation. For example, an action which allows clients to send emails to a contact may be able to accept attachments as a parameter to invocation. Each action must be invoked on an action target or list of targets, where a target may be a contact or a specific detail of a particular contact. See the Qt Contacts Action API documentation for more information on this topic. Non-Client-Facing APIThe non-client-facing API allows third party developers to implement a manager engine plugin from which clients may request data. Manager EngineThe functionality exposed by the QContactManager class may be implemented by engine plugins which interface directly to a platform-specific backend or provide their own data storage backend. As such, the terms "manager", "plugin" and "backend" are used interchangeably in this documentation to refer to any engine plugin which implements the functionality exposed by the QContactManager interface. The plugin architecture allows dynamic loading of different manager engines at runtime. A manager backend may be implemented by subclassing QContactManagerEngine, and providing a QContactManagerEngineFactory which can instantiate it when required. See Qt Contacts Manager Engines for more information on available engines and how to write your own engine. Using the APISome examples of common usage of the API may be found here. Building and compilingTo build the library, see the Qt Mobility installation instructions. Reference documentationMain classes
"Contact Details" Leaf ClassesSeveral subclasses of QContactDetail are provided as part of the Qt Mobility Project Contacts API. They are general in design but are intended to fulfill specific use-cases. Please note that certain backends may choose not to support one or more of these subclasses as they appear here; they may offer their own which provide similar functionality.
Each of these subclasses provide access to information stored in fields which may have certain constraints, as listed in the schema. Asynchronous RequestsClients may use either the synchronous or asynchronous API to access functionality provided by a manager backend. The asynchronous API is offered through subclasses of the QContactAbstractRequest class:
Contact SelectionClients may select a contact by specifying a unique contact id, or by supplying a QContactFilter which matches the contact or contacts they wish to select. The various derivatives of QContactFilter allow for fine-grained and flexible selection of contacts according to various criteria:
A client can also request that the results of such a selection be sorted, by passing a QContactSortOrder (or list of sort orders) to the manager. ActionsActions are described by descriptors and are instantiated by factories.
Implementing BackendsA backend implementor must implement the following interfaces:
For more information on this topic, see please see the documentation on implementing manager engines. Synchronization and SerializationThe contacts API is used by another Qt Mobility module: the Versit* module. It allows serialization of a QContact into a vCard document, and vice versa. [*] Versit ® is a trademark of the Internet Mail Consortium. ExamplesThe following sample applications show examples of API usage: See also: Contacts API Usage QML ElementsFor details on the QML support provided for the Contacts API see the documentation for the Contacts QML Plugin. X
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