PreferenceDataStoreDelegateKt

public final class PreferenceDataStoreDelegateKt


Summary

Public methods

static final @NonNull ReadOnlyProperty<@NonNull Context, @NonNull DataStore<@NonNull Preferences>>
preferencesDataStore(
    String name,
    ReplaceFileCorruptionHandler<Preferences> corruptionHandler,
    Function1<ContextList<DataMigration<Preferences>>> produceMigrations,
    CoroutineScope scope
)

Creates a property delegate for a single process DataStore.

Public methods

preferencesDataStore

public static final @NonNull ReadOnlyProperty<@NonNull Context, @NonNull DataStore<@NonNull Preferences>> preferencesDataStore(
    String name,
    ReplaceFileCorruptionHandler<Preferences> corruptionHandler,
    Function1<ContextList<DataMigration<Preferences>>> produceMigrations,
    CoroutineScope scope
)

Creates a property delegate for a single process DataStore. This should only be called once in a file (at the top level), and all usages of the DataStore should use a reference the same Instance. The receiver type for the property delegate must be an instance of Context.

This should only be used from a single application in a single classloader in a single process.

Example usage:

val Context.myDataStore by preferencesDataStore("filename")

class SomeClass(val context: Context) {
suspend fun update() = context.myDataStore.edit {...}
}
Parameters
String name

The name of the preferences. The preferences will be stored in a file in the "datastore/" subdirectory in the application context's files directory and is generated using preferencesDataStoreFile.

ReplaceFileCorruptionHandler<Preferences> corruptionHandler

The corruptionHandler is invoked if DataStore encounters a androidx.datastore.core.CorruptionException when attempting to read data. CorruptionExceptions are thrown by serializers when data can not be de-serialized.

Function1<ContextList<DataMigration<Preferences>>> produceMigrations

produce the migrations. The ApplicationContext is passed in to these callbacks as a parameter. DataMigrations are run before any access to data can occur. Each producer and migration may be run more than once whether or not it already succeeded (potentially because another migration failed or a write to disk failed.)

CoroutineScope scope

The scope in which IO operations and transform functions will execute.

Returns
@NonNull ReadOnlyProperty<@NonNull Context, @NonNull DataStore<@NonNull Preferences>>

a property delegate that manages a datastore as a singleton.