SavedStateReader

Artifact: androidx.savedstate:savedstate

Kotlin |Java

value public final class SavedStateReader

An inline class that encapsulates an opaque SavedState, and provides an API for reading the platform specific state.

See also
`read`

Summary

Public methods
`final boolean`	`contains(@NonNull String key)` Checks if the `SavedState` contains the specified `key`.
`final boolean`	`getBoolean(@NonNull String key)` Retrieves a `Boolean` value associated with the specified `key`.
`final boolean`	`getBooleanOrElse( @NonNull String key, @NonNull Function0<@NonNull Boolean> defaultValue )` Retrieves a `Boolean` value associated with the specified `key`, or a default value if the `key` doesn't exist.
`final double`	`getDouble(@NonNull String key)` Retrieves a `Double` value associated with the specified `key`.
`final double`	`getDoubleOrElse( @NonNull String key, @NonNull Function0<@NonNull Double> defaultValue )` Retrieves a `Double` value associated with the specified `key`, or a default value if the `key` doesn't exist.
`final float`	`getFloat(@NonNull String key)` Retrieves a `Float` value associated with the specified `key`.
`final float`	`getFloatOrElse( @NonNull String key, @NonNull Function0<@NonNull Float> defaultValue )` Retrieves a `Float` value associated with the specified `key`, or a default value if the `key` doesn't exist.
`final int`	`getInt(@NonNull String key)` Retrieves an `Int` value associated with the specified `key`.
`final @NonNull List<@NonNull Integer>`	`getIntList(@NonNull String key)` Retrieves a `List` of elements of `Int` associated with the specified `key`.
`final @NonNull List<@NonNull Integer>`	`getIntListOrElse( @NonNull String key, @NonNull Function0<@NonNull List<@NonNull Integer>> defaultValue )` Retrieves a `List` of elements of `Int` associated with the specified `key`, or a default value if the `key` doesn't exist.
`final int`	`getIntOrElse( @NonNull String key, @NonNull Function0<@NonNull Integer> defaultValue )` Retrieves an `Int` value associated with the specified `key`, or a default value if the `key` doesn't exist.
`final @NonNull T`	`<T extends Parcelable> getParcelable(@NonNull String key)` Retrieves a `Parcelable` object associated with the specified key.
`final @NonNull List<@NonNull T>`	`<T extends Parcelable> getParcelableList(@NonNull String key)` Retrieves a `List` of elements of `Parcelable` associated with the specified `key`.
`final @NonNull List<@NonNull T>`	`<T extends Parcelable> getParcelableListOrElse( @NonNull String key, @NonNull Function0<@NonNull List<@NonNull T>> defaultValue )` Retrieves a `List` of elements of `Parcelable` associated with the specified `key`, or a default value if the `key` doesn't exist.
`final @NonNull T`	`<T extends Parcelable> getParcelableOrElse( @NonNull String key, @NonNull Function0<@NonNull T> defaultValue )` Retrieves a `Parcelable` object associated with the specified key, or a default value if the key doesn't exist.
`final @NonNull SavedState`	`getSavedState(@NonNull String key)` Retrieves a `SavedState` object associated with the specified `key`.
`final @NonNull SavedState`	`getSavedStateOrElse( @NonNull String key, @NonNull Function0<@NonNull SavedState> defaultValue )` Retrieves a `SavedState` object associated with the specified `key`, or a default value if the `key` doesn't exist.
`final @NonNull String`	`getString(@NonNull String key)` Retrieves a `String` value associated with the specified `key`.
`final @NonNull List<@NonNull String>`	`getStringList(@NonNull String key)` Retrieves a `List` of elements of `String` associated with the specified `key`.
`final @NonNull List<@NonNull String>`	`getStringListOrElse( @NonNull String key, @NonNull Function0<@NonNull List<@NonNull String>> defaultValue )` Retrieves a `List` of elements of `String` associated with the specified `key`, or a default value if the `key` doesn't exist.
`final @NonNull String`	`getStringOrElse( @NonNull String key, @NonNull Function0<@NonNull String> defaultValue )` Retrieves a `String` value associated with the specified `key`, or a default value if the `key` doesn't exist.
`final boolean`	`isEmpty()` Checks if the `SavedState` is empty (contains no key-value pairs).
`final int`	`size()` Returns the number of key-value pairs in the `SavedState`.

Extension functions
`final @NonNull T`	`<T extends Object> SavedStateKt.write( @NonNull SavedStateReader receiver, @ExtensionFunctionType @NonNull Function1<@NonNull SavedStateWriter, @NonNull T> block )` Calls the specified function `block` with a `SavedStateWriter` value as its receiver and returns the `block` value.

Public methods

contains

Added in 1.3.0-alpha02

public final boolean contains(@NonNull String key)

Checks if the SavedState contains the specified key.

Parameters
`@NonNull String key`	The `key` to check for.

Returns
`boolean`	`true` if the `SavedState` contains the `key`, `false` otherwise.

getBoolean

Added in 1.3.0-alpha02

public final boolean getBoolean(@NonNull String key)

Retrieves a Boolean value associated with the specified key. Throws an IllegalStateException if the key doesn't exist.

Parameters
`@NonNull String key`	The `key` to retrieve the value for.

Returns
`boolean`	The `Boolean` value associated with the `key`.

Throws
`kotlin.IllegalStateException`	If the `key` is not found.

getBooleanOrElse

Added in 1.3.0-alpha02

public final boolean getBooleanOrElse(
    @NonNull String key,
    @NonNull Function0<@NonNull Boolean> defaultValue
)

Retrieves a Boolean value associated with the specified key, or a default value if the key doesn't exist.

Parameters
`@NonNull String key`	The `key` to retrieve the value for.
`@NonNull Function0<@NonNull Boolean> defaultValue`	A function providing the default value if the `key` is not found.

Returns
`boolean`	The `Boolean` value associated with the `key`, or the default value if the `key` is not found.

getDouble

Added in 1.3.0-alpha02

public final double getDouble(@NonNull String key)

Retrieves a Double value associated with the specified key. Throws an IllegalStateException if the key doesn't exist.

Parameters
`@NonNull String key`	The `key` to retrieve the value for.

Returns
`double`	The `Double` value associated with the `key`.

Throws
`kotlin.IllegalStateException`	If the `key` is not found.

getDoubleOrElse

Added in 1.3.0-alpha02

public final double getDoubleOrElse(
    @NonNull String key,
    @NonNull Function0<@NonNull Double> defaultValue
)

Retrieves a Double value associated with the specified key, or a default value if the key doesn't exist.

Parameters
`@NonNull String key`	The `key` to retrieve the value for.
`@NonNull Function0<@NonNull Double> defaultValue`	A function providing the default value if the `key` is not found.

Returns
`double`	The `Double` value associated with the `key`, or the default value if the `key` is not found.

getFloat

Added in 1.3.0-alpha02

public final float getFloat(@NonNull String key)

Retrieves a Float value associated with the specified key. Throws an IllegalStateException if the key doesn't exist.

Parameters
`@NonNull String key`	The `key` to retrieve the value for.

Returns
`float`	The `Float` value associated with the `key`.

Throws
`kotlin.IllegalStateException`	If the `key` is not found.

getFloatOrElse

Added in 1.3.0-alpha02

public final float getFloatOrElse(
    @NonNull String key,
    @NonNull Function0<@NonNull Float> defaultValue
)

Retrieves a Float value associated with the specified key, or a default value if the key doesn't exist.

Parameters
`@NonNull String key`	The `key` to retrieve the value for.
`@NonNull Function0<@NonNull Float> defaultValue`	A function providing the default value if the `key` is not found.

Returns
`float`	The `Float` value associated with the `key`, or the default value if the `key` is not found.

getInt

Added in 1.3.0-alpha02

public final int getInt(@NonNull String key)

Retrieves an Int value associated with the specified key. Throws an IllegalStateException if the key doesn't exist.

Parameters
`@NonNull String key`	The `key` to retrieve the value for.

Returns
`int`	The `Int` value associated with the `key`.

Throws
`kotlin.IllegalStateException`	If the `key` is not found.

getIntList

Added in 1.3.0-alpha02

public final @NonNull List<@NonNull Integer> getIntList(@NonNull String key)

Retrieves a List of elements of Int associated with the specified key. Throws an IllegalStateException if the key doesn't exist.

Parameters
`@NonNull String key`	The `key` to retrieve the value for.

Returns
`@NonNull List<@NonNull Integer>`	The `List` of elements of `Int` associated with the `key`.

Throws
`kotlin.IllegalStateException`	If the `key` is not found.

getIntListOrElse

Added in 1.3.0-alpha02

public final @NonNull List<@NonNull Integer> getIntListOrElse(
    @NonNull String key,
    @NonNull Function0<@NonNull List<@NonNull Integer>> defaultValue
)

Retrieves a List of elements of Int associated with the specified key, or a default value if the key doesn't exist.

Parameters
`@NonNull String key`	The `key` to retrieve the value for.
`@NonNull Function0<@NonNull List<@NonNull Integer>> defaultValue`	A function providing the default value if the `key` is not found or the retrieved value is not a list of `Int`.

Returns
`@NonNull List<@NonNull Integer>`	The list of elements of `Int` associated with the `key`, or the default value if the `key` is not found.

getIntOrElse

Added in 1.3.0-alpha02

public final int getIntOrElse(
    @NonNull String key,
    @NonNull Function0<@NonNull Integer> defaultValue
)

Retrieves an Int value associated with the specified key, or a default value if the key doesn't exist.

Parameters
`@NonNull String key`	The `key` to retrieve the value for.
`@NonNull Function0<@NonNull Integer> defaultValue`	A function providing the default value if the `key` is not found.

Returns
`int`	The `Int` value associated with the `key`, or the default value if the `key` is not found.

getParcelable

public final @NonNull T <T extends Parcelable> getParcelable(@NonNull String key)

Retrieves a Parcelable object associated with the specified key. Throws an IllegalStateException if the key doesn't exist.

Parameters
`@NonNull String key`	The key to retrieve the value for.

Returns
`@NonNull T`	The `Parcelable` object associated with the key.

Throws
`kotlin.IllegalStateException`	If the key is not found.

getParcelableList

public final @NonNull List<@NonNull T> <T extends Parcelable> getParcelableList(@NonNull String key)

Retrieves a List of elements of Parcelable associated with the specified key. Throws an IllegalStateException if the key doesn't exist.

Parameters
`@NonNull String key`	The `key` to retrieve the value for.

Returns
`@NonNull List<@NonNull T>`	The `List` of elements of `Parcelable` associated with the `key`.

Throws
`kotlin.IllegalStateException`	If the `key` is not found.

getParcelableListOrElse

public final @NonNull List<@NonNull T> <T extends Parcelable> getParcelableListOrElse(
    @NonNull String key,
    @NonNull Function0<@NonNull List<@NonNull T>> defaultValue
)

Retrieves a List of elements of Parcelable associated with the specified key, or a default value if the key doesn't exist.

Parameters
`@NonNull String key`	The `key` to retrieve the value for.
`@NonNull Function0<@NonNull List<@NonNull T>> defaultValue`	A function providing the default value if the `key` is not found or the retrieved value is not a list of `Parcelable`.

Returns
`@NonNull List<@NonNull T>`	The list of elements of `Parcelable` associated with the `key`, or the default value if the `key` is not found.

getParcelableOrElse

public final @NonNull T <T extends Parcelable> getParcelableOrElse(
    @NonNull String key,
    @NonNull Function0<@NonNull T> defaultValue
)

Retrieves a Parcelable object associated with the specified key, or a default value if the key doesn't exist.

Parameters
`@NonNull String key`	The key to retrieve the value for.
`@NonNull Function0<@NonNull T> defaultValue`	A function providing the default `Parcelable` if the key is not found.

Returns
`@NonNull T`	The `Parcelable` object associated with the key, or the default value if the key is not found.

getSavedState

Added in 1.3.0-alpha02

public final @NonNull SavedState getSavedState(@NonNull String key)

Retrieves a SavedState object associated with the specified key. Throws an IllegalStateException if the key doesn't exist.

Parameters
`@NonNull String key`	The `key` to retrieve the value for.

Returns
`@NonNull SavedState`	The `SavedState` object associated with the `key`.

Throws
`kotlin.IllegalStateException`	If the `key` is not found.

getSavedStateOrElse

public final @NonNull SavedState getSavedStateOrElse(
    @NonNull String key,
    @NonNull Function0<@NonNull SavedState> defaultValue
)

Retrieves a SavedState object associated with the specified key, or a default value if the key doesn't exist.

Parameters
`@NonNull String key`	The `key` to retrieve the value for.
`@NonNull Function0<@NonNull SavedState> defaultValue`	A function providing the default `SavedState` if the `key` is not found.

Returns
`@NonNull SavedState`	The `SavedState` object associated with the `key`, or the default value if the `key` is not found.

getString

Added in 1.3.0-alpha02

public final @NonNull String getString(@NonNull String key)

Retrieves a String value associated with the specified key. Throws an IllegalStateException if the key doesn't exist.

Parameters
`@NonNull String key`	The `key` to retrieve the value for.

Returns
`@NonNull String`	The `String` value associated with the `key`.

Throws
`kotlin.IllegalStateException`	If the `key` is not found.

getStringList

Added in 1.3.0-alpha02

public final @NonNull List<@NonNull String> getStringList(@NonNull String key)

Retrieves a List of elements of String associated with the specified key. Throws an IllegalStateException if the key doesn't exist.

Parameters
`@NonNull String key`	The `key` to retrieve the value for.

Returns
`@NonNull List<@NonNull String>`	The `List` of elements of `String` associated with the `key`.

Throws
`kotlin.IllegalStateException`	If the `key` is not found.

getStringListOrElse

Added in 1.3.0-alpha02

public final @NonNull List<@NonNull String> getStringListOrElse(
    @NonNull String key,
    @NonNull Function0<@NonNull List<@NonNull String>> defaultValue
)

Retrieves a List of elements of String associated with the specified key, or a default value if the key doesn't exist.

Parameters
`@NonNull String key`	The `key` to retrieve the value for.
`@NonNull Function0<@NonNull List<@NonNull String>> defaultValue`	A function providing the default value if the `key` is not found or the retrieved value is not a list of `String`.

Returns
`@NonNull List<@NonNull String>`	The list of elements of `String` associated with the `key`, or the default value if the `key` is not found.

getStringOrElse

Added in 1.3.0-alpha02

public final @NonNull String getStringOrElse(
    @NonNull String key,
    @NonNull Function0<@NonNull String> defaultValue
)

Retrieves a String value associated with the specified key, or a default value if the key doesn't exist.

Parameters
`@NonNull String key`	The `key` to retrieve the value for.
`@NonNull Function0<@NonNull String> defaultValue`	A function providing the default value if the `key` is not found.

Returns
`@NonNull String`	The `String` value associated with the `key`, or the default value if the `key` is not found.

isEmpty

Added in 1.3.0-alpha02

public final boolean isEmpty()

Checks if the SavedState is empty (contains no key-value pairs).

Returns
`boolean`	`true` if the `SavedState` is empty, `false` otherwise.

size

Added in 1.3.0-alpha02

public final int size()

Returns the number of key-value pairs in the SavedState.

Returns
`int`	The size of the `SavedState`.

Extension functions

SavedStateKt.write

Artifact: androidx.savedstate:savedstate

View Source

public final @NonNull T <T extends Object> SavedStateKt.write(
    @NonNull SavedStateReader receiver,
    @ExtensionFunctionType @NonNull Function1<@NonNull SavedStateWriter, @NonNull T> block
)

Calls the specified function block with a SavedStateWriter value as its receiver and returns the block value.

Parameters
`@ExtensionFunctionType @NonNull Function1<@NonNull SavedStateWriter, @NonNull T> block`	A lambda function that performs write operations using the `SavedStateWriter`.

Returns
`@NonNull T`	The result of the lambda function's execution.

See also
`SavedStateReader`
`SavedStateWriter`