harmony 鸿蒙oh_preferences.h

2025-06-12
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oh_preferences.h

Overview

Provides APIs and structs for accessing the Preferences object.

File to include: <database/preferences/oh_preferences.h>

Library: libohpreferences.so

System capability: SystemCapability.DistributedDataManager.Preferences.Core

Since: 13

Related module: Preferences

Summary

Types

Name	Description
typedef struct OH_Preferences OH_Preferences	Defines a Preferences object.
typedef void(* OH_PreferencesDataObserver) (void context, const OH_PreferencesPair pairs, uint32_t count)	Defines the callback to be invoked when data changes.

Functions

Name	Description
OH_Preferences * OH_Preferences_Open (OH_PreferencesOption option, int errCode)	Opens a Preferences instance and creates a pointer to it. If this pointer is no longer required, use OH_Preferences_Close to close the instance.
int OH_Preferences_Close (OH_Preferences *preference)	Closes a Preferences instance.
int OH_Preferences_GetInt (OH_Preferences preference, const char key, int *value)	Obtains an integer corresponding to the specified key in a Preferences instance.
int OH_Preferences_GetBool (OH_Preferences preference, const char key, bool *value)	Obtains a Boolean value corresponding to the specified key in a Preferences instance.
int OH_Preferences_GetString (OH_Preferences preference, const char key, char *value, uint32_t valueLen)	Obtains a string corresponding to the specified key in a Preferences instance.
void OH_Preferences_FreeString (char *string)	Releases a string.
int OH_Preferences_SetInt (OH_Preferences preference, const char key, int value)	Sets an integer value based on the specified key in a Preferences instance.
int OH_Preferences_SetBool (OH_Preferences preference, const char key, bool value)	Sets a Boolean value based on the specified key in a Preferences instance.
int OH_Preferences_SetString (OH_Preferences preference, const char key, const char *value)	Sets a string based on the specified key in a Preferences instance.
int OH_Preferences_Delete (OH_Preferences preference, const char key)	Deletes a KV pair of the specified key from a Preferences object.
int OH_Preferences_RegisterDataObserver (OH_Preferences preference, void context, OH_PreferencesDataObserver observer, const char *keys[], uint32_t keyCount)	Subscribes to data changes of the specified key. If the value of the specified key changes, a callback will be invoked after OH_Preferences_Close () is called.
int OH_Preferences_UnregisterDataObserver (OH_Preferences preference, void context, OH_PreferencesDataObserver observer, const char *keys[], uint32_t keyCount)	Unsubscribes from data changes of the specified key.
int OH_Preferences_IsStorageTypeSupported (Preferences_StorageType type, bool *isSupported)	Checks whether the specified storage type is supported.