android.os.Parcelable Maven / Gradle / Ivy
/*
* Copyright (C) 2006 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.os;
import android.annotation.IntDef;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
/**
* Interface for classes whose instances can be written to
* and restored from a {@link Parcel}. Classes implementing the Parcelable
* interface must also have a non-null static field called CREATOR
* of a type that implements the {@link Creator} interface.
*
* A typical implementation of Parcelable is:
*
*
* public class MyParcelable implements Parcelable {
* private int mData;
*
* public int describeContents() {
* return 0;
* }
*
* public void writeToParcel(Parcel out, int flags) {
* out.writeInt(mData);
* }
*
* public static final Parcelable.Creator<MyParcelable> CREATOR
* = new Parcelable.Creator<MyParcelable>() {
* public MyParcelable createFromParcel(Parcel in) {
* return new MyParcelable(in);
* }
*
* public MyParcelable[] newArray(int size) {
* return new MyParcelable[size];
* }
* };
*
* private MyParcelable(Parcel in) {
* mData = in.readInt();
* }
* }
*/
public interface Parcelable {
@IntDef(flag = true, prefix = { "PARCELABLE_" }, value = {
PARCELABLE_WRITE_RETURN_VALUE,
PARCELABLE_ELIDE_DUPLICATES,
})
@Retention(RetentionPolicy.SOURCE)
public @interface WriteFlags {}
/**
* Flag for use with {@link #writeToParcel}: the object being written
* is a return value, that is the result of a function such as
* "Parcelable someFunction()",
* "void someFunction(out Parcelable)", or
* "void someFunction(inout Parcelable)". Some implementations
* may want to release resources at this point.
*/
public static final int PARCELABLE_WRITE_RETURN_VALUE = 0x0001;
/**
* Flag for use with {@link #writeToParcel}: a parent object will take
* care of managing duplicate state/data that is nominally replicated
* across its inner data members. This flag instructs the inner data
* types to omit that data during marshaling. Exact behavior may vary
* on a case by case basis.
*/
public static final int PARCELABLE_ELIDE_DUPLICATES = 0x0002;
/*
* Bit masks for use with {@link #describeContents}: each bit represents a
* kind of object considered to have potential special significance when
* marshalled.
*/
@IntDef(flag = true, prefix = { "CONTENTS_" }, value = {
CONTENTS_FILE_DESCRIPTOR,
})
@Retention(RetentionPolicy.SOURCE)
public @interface ContentsFlags {}
/**
* Descriptor bit used with {@link #describeContents()}: indicates that
* the Parcelable object's flattened representation includes a file descriptor.
*
* @see #describeContents()
*/
public static final int CONTENTS_FILE_DESCRIPTOR = 0x0001;
/**
* Describe the kinds of special objects contained in this Parcelable
* instance's marshaled representation. For example, if the object will
* include a file descriptor in the output of {@link #writeToParcel(Parcel, int)},
* the return value of this method must include the
* {@link #CONTENTS_FILE_DESCRIPTOR} bit.
*
* @return a bitmask indicating the set of special object types marshaled
* by this Parcelable object instance.
*/
public @ContentsFlags int describeContents();
/**
* Flatten this object in to a Parcel.
*
* @param dest The Parcel in which the object should be written.
* @param flags Additional flags about how the object should be written.
* May be 0 or {@link #PARCELABLE_WRITE_RETURN_VALUE}.
*/
public void writeToParcel(Parcel dest, @WriteFlags int flags);
/**
* Interface that must be implemented and provided as a public CREATOR
* field that generates instances of your Parcelable class from a Parcel.
*/
public interface Creator {
/**
* Create a new instance of the Parcelable class, instantiating it
* from the given Parcel whose data had previously been written by
* {@link Parcelable#writeToParcel Parcelable.writeToParcel()}.
*
* @param source The Parcel to read the object's data from.
* @return Returns a new instance of the Parcelable class.
*/
public T createFromParcel(Parcel source);
/**
* Create a new array of the Parcelable class.
*
* @param size Size of the array.
* @return Returns an array of the Parcelable class, with every entry
* initialized to null.
*/
public T[] newArray(int size);
}
/**
* Specialization of {@link Creator} that allows you to receive the
* ClassLoader the object is being created in.
*/
public interface ClassLoaderCreator extends Creator {
/**
* Create a new instance of the Parcelable class, instantiating it
* from the given Parcel whose data had previously been written by
* {@link Parcelable#writeToParcel Parcelable.writeToParcel()} and
* using the given ClassLoader.
*
* @param source The Parcel to read the object's data from.
* @param loader The ClassLoader that this object is being created in.
* @return Returns a new instance of the Parcelable class.
*/
public T createFromParcel(Parcel source, ClassLoader loader);
}
}