Android example source code file (AbsSavedState.java)

This example Android source code file (AbsSavedState.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

abssavedstate, android, creator, empty_state, illegalargumentexception, illegalstateexception, os, parcelable

The AbsSavedState.java Android example source code

/*
 * 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.view;

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

/**
 * A {@link Parcelable} implementation that should be used by inheritance
 * hierarchies to ensure the state of all classes along the chain is saved.
 */
public abstract class AbsSavedState implements Parcelable {
    public static final AbsSavedState EMPTY_STATE = new AbsSavedState() {};

    private final Parcelable mSuperState;

    /**
     * Constructor used to make the EMPTY_STATE singleton
     */
    private AbsSavedState() {
        mSuperState = null;
    }

    /**
     * Constructor called by derived classes when creating their SavedState objects
     * 
     * @param superState The state of the superclass of this view
     */
    protected AbsSavedState(Parcelable superState) {
        if (superState == null) {
            throw new IllegalArgumentException("superState must not be null");
        }
        mSuperState = superState != EMPTY_STATE ? superState : null;
    }

    /**
     * Constructor used when reading from a parcel. Reads the state of the superclass.
     * 
     * @param source
     */
    protected AbsSavedState(Parcel source) {
        // FIXME need class loader
        Parcelable superState = (Parcelable) source.readParcelable(null);
         
        mSuperState = superState != null ? superState : EMPTY_STATE;
    }

    final public Parcelable getSuperState() {
        return mSuperState;
    }

    public int describeContents() {
        return 0;
    }

    public void writeToParcel(Parcel dest, int flags) {
         dest.writeParcelable(mSuperState, flags);
    }

    public static final Parcelable.Creator<AbsSavedState> CREATOR 
        = new Parcelable.Creator<AbsSavedState>() {
        
        public AbsSavedState createFromParcel(Parcel in) {
            Parcelable superState = (Parcelable) in.readParcelable(null);
            if (superState != null) {
                throw new IllegalStateException("superState must be null");
            }
            return EMPTY_STATE;
        }

        public AbsSavedState[] newArray(int size) {
            return new AbsSavedState[size];
        }
    };
}