Android 实现Parcelable接口序列化对象


关于对象序列化的方法，在Android中常用到的一般有两种，一种是可以通过实现Serializable接口，这也是java语言中常用的序列化方法，别外一种就是实现Parcelable接口，这是android所特有的。这两个接口，实现Serializable接口相对简单，声明一下就可以了，而实现Parcelable接口相对要复杂一些，但是android过程中，效率较Serializable要高一些，所以推荐使用实现Parcelable接口的方法来序列化对象。

通过Parcelable接口序列化对象一般要通过以下几个步骤：

1，声明实现Parcelable接口。

2，覆写writeToParcel方法，将对象序列化为Parcel对象。

3，实现内部Parcelable.Creator<T>对象，覆写createFromParcel方法，来将对象反序列化。

下面贴上Android代码中通过实现Parcelable接口序列化对象的例子：

/*
* Copyright (C) 2009 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.accounts;

import android.os.Parcelable;
import android.os.Parcel;
import android.text.TextUtils;

/**
* Value type that represents an Account in the {@link AccountManager}. This object is
* {@link Parcelable} and also overrides {@link #equals} and {@link #hashCode}, making it
* suitable for use as the key of a {@link java.util.Map}
*/
public class Account implements Parcelable {
public final String name;
public final String type;

public boolean equals(Object o) {
if (o == this) return true;
if (!(o instanceof Account)) return false;
final Account other = (Account)o;
return name.equals(other.name) && type.equals(other.type);
}

public int hashCode() {
int result = 17;
result = 31 * result + name.hashCode();
result = 31 * result + type.hashCode();
return result;
}

public Account(String name, String type) {
if (TextUtils.isEmpty(name)) {
throw new IllegalArgumentException("the name must not be empty: " + name);
}
if (TextUtils.isEmpty(type)) {
throw new IllegalArgumentException("the type must not be empty: " + type);
}
this.name = name;
this.type = type;
}

public Account(Parcel in) {
this.name = in.readString();
this.type = in.readString();
}

public int describeContents() {
return 0;
}

public void writeToParcel(Parcel dest, int flags) {
dest.writeString(name);
dest.writeString(type);
}

public static final Creator<Account> CREATOR = new Creator<Account>() {
public Account createFromParcel(Parcel source) {
return new Account(source);
}

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

public String toString() {
return "Account {name=" + name + ", type=" + type + "}";
}
}

对象序列化的一个好处，就是可以很方便的通过Intent来传递数据，可以直接传递一个对象，也可以通过putParcelableArrayListExtra方法，直接传递一个序列化对象的数组。