ParcelableCompat.java

/*
 * Copyright (C) 2011 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.support.v4.os;

import android.os.Parcel;
import android.os.Parcelable;

/**
 * Helper for accessing features in {@link android.os.Parcelable}
 * introduced after API level 4 in a backwards compatible fashion.
 */
public class ParcelableCompat {

	/**
	 * Callbacks a {@link Parcelable} creator should implement.
	 */
	public interface ParcelableCompatCreatorCallbacks<T> {

	    /**
	     * 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 in 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 in, ClassLoader loader);

	    /**
	     * 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);
	}
	
    /**
     * Factory method for {@link Parcelable.Creator}.
     *
     * @param callbacks Creator callbacks implementation.
     * @return New creator.
     */
    public static <T> Parcelable.Creator<T> newCreator(
            ParcelableCompatCreatorCallbacks<T> callbacks) {
        if (android.os.Build.VERSION.SDK_INT >= 13) {
            ParcelableCompatCreatorHoneycombMR2Stub.instantiate(callbacks);
        }
        return new CompatCreator<T>(callbacks);
    }

    static class CompatCreator<T> implements Parcelable.Creator<T> {
        final ParcelableCompatCreatorCallbacks<T> mCallbacks;

        public CompatCreator(ParcelableCompatCreatorCallbacks<T> callbacks) {
            mCallbacks = callbacks;
        }

        @Override
        public T createFromParcel(Parcel source) {
            return mCallbacks.createFromParcel(source, null);
        }

        @Override
        public T[] newArray(int size) {
            return mCallbacks.newArray(size);
        }
    }
}