Android中Intent傳遞對象的兩種方法(Serializable,Parcelable)

一.序列化原因：

1.永久性保存對象，保存對象的字節序列到本地文件中；
2.通過序列化對象在網絡中傳遞對象；
3.通過序列化在進程間傳遞對象。

二.至於選取哪種可參考下面的原則：

1.在使用內存的時候，Parcelable 類比Serializable性能高，所以推薦使用Parcelable類。
2.Serializable在序列化的時候會產生大量的臨時變量，從而引起頻繁的GC。
3.Parcelable不能使用在要將數據存儲在磁盤上的情況，因爲Parcelable不能很好的保證數據的持續性在外界有變化的情況下。儘管Serializable效率低點， 也不提倡用，但在這種情況下，還是建議你用Serializable 。

實現：
1.Serializable 的實現

只需要繼承  implements Serializable 即可。這只是給對象打了一個標記，系統會自動將其序列化。

2.Parcelabel 的實現

1）writeToParcel 方法。該方法將類的數據寫入外部提供的Parcel中.聲明如下：writeToParcel (Parcel dest, int flags) 具體參數含義見javadoc

2）describeContents方法。沒搞懂有什麼用，反正直接返回0也可以

3）靜態的Parcelable.Creator接口，本接口有兩個方法：

createFromParcel(Parcel in) 實現從in中創建出類的實例的功能

newArray(int size) 創建一個類型爲T，長度爲size的數組，僅一句話（return new T[size])即可。估計本方法是供外部類反序列化本類數組使用。

新建兩個類一個是Person.java實現Serializable接口，另一個Book.java實現Parcelable接口，代碼分別如下:
Person.java

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import java.io.Serializable; public class Person implements Serializable {     private static final long serialVersionUID = -7060210544600464481L;     private String name;     private int age;     public String getName() {         return name;     }     public void setName(String name) {         this.name = name;     }     public int getAge() {         return age;     }     public void setAge(int age) {         this.age = age;     }   }

Book.java

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import android.os.Parcel; import android.os.Parcelable; public class Book implements Parcelable {     private String bookName;     private String author;     private int publishTime;       public String getBookName() {         return bookName;     }     public void setBookName(String bookName) {         this.bookName = bookName;     }     public String getAuthor() {         return author;     }     public void setAuthor(String author) {         this.author = author;     }     public int getPublishTime() {         return publishTime;     }     public void setPublishTime(int publishTime) {         this.publishTime = publishTime;     }       public static final Parcelable.Creator<Book> CREATOR = new Creator<Book>() {        public Book createFromParcel(Parcel source) {          Book mBook = new Book();          mBook.bookName = source.readString();          mBook.author = source.readString();          mBook.publishTime = source.readInt();          return mBook;        }        public Book[] newArray(int size) {          return new Book[size];        }     };       public int describeContents() {       return 0;     }     public void writeToParcel(Parcel parcel, int flags) {       parcel.writeString(bookName);       parcel.writeString(author);       parcel.writeInt(publishTime);     } }

下面還後一個demo
第一步:新建一個Android工程命名爲ObjectTranDemo(類比較多哦!)目錄結構如下圖:

第二步:修改main.xml佈局文件(這裏我增加了兩個按鈕)代碼如下

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Welcome to Mr wei's blog."
    />
<Button
    android:id="@+id/button1"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Serializable"
/>
<Button
    android:id="@+id/button2"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Parcelable"
/>
</LinearLayout>

 

第三步:新建兩個類一個是Person.java實現Serializable接口，另一個Book.java實現Parcelable接口，代碼分別如下:

Person.java:

 

package com.tutor.objecttran;
import java.io.Serializable;
public class Person implements Serializable {
    private static final long serialVersionUID = -7060210544600464481L;
    private String name;
    private int age;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }

}

 

Book.java:

 

package com.tutor.objecttran;
import android.os.Parcel;
import android.os.Parcelable;
public class Book implements Parcelable {
    private String bookName;
    private String author;
    private int publishTime;

    public String getBookName() {
        return bookName;
    }
    public void setBookName(String bookName) {
        this.bookName = bookName;
    }
    public String getAuthor() {
        return author;
    }
    public void setAuthor(String author) {
        this.author = author;
    }
    public int getPublishTime() {
        return publishTime;
    }
    public void setPublishTime(int publishTime) {
        this.publishTime = publishTime;
    }

    public static final Parcelable.Creator<Book> CREATOR = new Creator<Book>() {
        public Book createFromParcel(Parcel source) {
            Book mBook = new Book();
            mBook.bookName = source.readString();
            mBook.author = source.readString();
            mBook.publishTime = source.readInt();
            return mBook;
        }
        public Book[] newArray(int size) {
            return new Book[size];
        }
    };

    public int describeContents() {
        return 0;
    }
    public void writeToParcel(Parcel parcel, int flags) {
        parcel.writeString(bookName);
        parcel.writeString(author);
        parcel.writeInt(publishTime);
    }
}

 

第四步:修改ObjectTranDemo.java,並且新建兩個Activity,一個是ObjectTranDemo1.java,別一個是ObjectTranDemo2.java.分別用來顯示Person對像數據，和Book對象數據:,代碼分別如下：

ObjectTranDemo.java:

 

package com.tutor.objecttran;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class ObjectTranDemo extends Activity implements OnClickListener {

    private Button sButton,pButton;
    public  final static String SER_KEY = "com.tutor.objecttran.ser";
    public  final static String PAR_KEY = "com.tutor.objecttran.par";
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        setupViews();

    }

    //我的一貫作風呵呵
    public void setupViews(){
        sButton = (Button)findViewById(R.id.button1);
        pButton = (Button)findViewById(R.id.button2);
        sButton.setOnClickListener(this);
        pButton.setOnClickListener(this);
    }
    //Serializeable傳遞對象的方法
    public void SerializeMethod(){
        Person mPerson = new Person();
        mPerson.setName("frankie");
        mPerson.setAge(25);
        Intent mIntent = new Intent(this,ObjectTranDemo1.class);
        Bundle mBundle = new Bundle();
        mBundle.putSerializable(SER_KEY,mPerson);
        mIntent.putExtras(mBundle);

        startActivity(mIntent);
    }
    //Pacelable傳遞對象方法
    public void PacelableMethod(){
        Book mBook = new Book();
        mBook.setBookName("Android Tutor");
        mBook.setAuthor("Frankie");
        mBook.setPublishTime(2010);
        Intent mIntent = new Intent(this,ObjectTranDemo2.class);
        Bundle mBundle = new Bundle();
        mBundle.putParcelable(PAR_KEY, mBook);
        mIntent.putExtras(mBundle);

        startActivity(mIntent);
    }
    //銨鈕點擊事件響應
    public void onClick(View v) {
        if(v == sButton){
            SerializeMethod();
        }else{
            PacelableMethod();
        }
    }
}

 

ObjectTranDemo1.java:

 

package com.tutor.objecttran;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class ObjectTranDemo1 extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        TextView mTextView = new TextView(this);
        Person mPerson = (Person)getIntent().getSerializableExtra(ObjectTranDemo.SER_KEY);
        mTextView.setText("You name is: " + mPerson.getName() + "/n"+
                "You age is: " + mPerson.getAge());

        setContentView(mTextView);
    }
}

 

ObjectTranDemo2.java:

 

package com.tutor.objecttran;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class ObjectTranDemo2 extends Activity {

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        TextView mTextView = new TextView(this);
        Book mBook = (Book)getIntent().getParcelableExtra(ObjectTranDemo.PAR_KEY);
        mTextView.setText("Book name is: " + mBook.getBookName()+"/n"+
                          "Author is: " + mBook.getAuthor() + "/n" +
                          "PublishTime is: " + mBook.getPublishTime());
        setContentView(mTextView);
    }
}

 

第五步:比較重要的一步啦，修改AndroidManifest.xml文件（將兩個新增的Activity，ObjectTranDemo1,ObjectTranDemo2)申明一下代碼如下(第14，15行):

 

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.tutor.objecttran"
      android:versionCode="1"
      android:versionName="1.0">
    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".ObjectTranDemo"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".ObjectTranDemo1"></activity>
        <activity android:name=".ObjectTranDemo2"></activity>
    </application>
    <uses-sdk android:minSdkVersion="7" />
</manifest>