The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2006 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package android.view; |
| 18 | |
| 19 | import android.os.Parcel; |
| 20 | import android.os.Parcelable; |
| 21 | |
| 22 | /** |
| 23 | * A {@link Parcelable} implementation that should be used by inheritance |
| 24 | * hierarchies to ensure the state of all classes along the chain is saved. |
| 25 | */ |
| 26 | public abstract class AbsSavedState implements Parcelable { |
| 27 | public static final AbsSavedState EMPTY_STATE = new AbsSavedState() {}; |
| 28 | |
| 29 | private final Parcelable mSuperState; |
| 30 | |
| 31 | /** |
| 32 | * Constructor used to make the EMPTY_STATE singleton |
| 33 | */ |
| 34 | private AbsSavedState() { |
| 35 | mSuperState = null; |
| 36 | } |
| 37 | |
| 38 | /** |
| 39 | * Constructor called by derived classes when creating their SavedState objects |
| 40 | * |
| 41 | * @param superState The state of the superclass of this view |
| 42 | */ |
| 43 | protected AbsSavedState(Parcelable superState) { |
| 44 | if (superState == null) { |
| 45 | throw new IllegalArgumentException("superState must not be null"); |
| 46 | } |
| 47 | mSuperState = superState != EMPTY_STATE ? superState : null; |
| 48 | } |
| 49 | |
| 50 | /** |
| 51 | * Constructor used when reading from a parcel. Reads the state of the superclass. |
| 52 | * |
| 53 | * @param source |
| 54 | */ |
| 55 | protected AbsSavedState(Parcel source) { |
| 56 | // FIXME need class loader |
| 57 | Parcelable superState = (Parcelable) source.readParcelable(null); |
| 58 | |
| 59 | mSuperState = superState != null ? superState : EMPTY_STATE; |
| 60 | } |
| 61 | |
| 62 | final public Parcelable getSuperState() { |
| 63 | return mSuperState; |
| 64 | } |
| 65 | |
| 66 | public int describeContents() { |
| 67 | return 0; |
| 68 | } |
| 69 | |
| 70 | public void writeToParcel(Parcel dest, int flags) { |
| 71 | dest.writeParcelable(mSuperState, flags); |
| 72 | } |
| 73 | |
| 74 | public static final Parcelable.Creator<AbsSavedState> CREATOR |
| 75 | = new Parcelable.Creator<AbsSavedState>() { |
| 76 | |
| 77 | public AbsSavedState createFromParcel(Parcel in) { |
| 78 | Parcelable superState = (Parcelable) in.readParcelable(null); |
| 79 | if (superState != null) { |
| 80 | throw new IllegalStateException("superState must be null"); |
| 81 | } |
| 82 | return EMPTY_STATE; |
| 83 | } |
| 84 | |
| 85 | public AbsSavedState[] newArray(int size) { |
| 86 | return new AbsSavedState[size]; |
| 87 | } |
| 88 | }; |
| 89 | } |