Intent传递对象的两种方法Serializable 和 Parcelable

Serializable 和 Parcelable的区别

1、作用

Serializable的作用是为了保存对象的属性到本地文件、数据库、网络流、rmi以方便数据传输，当然这种传输可以是程序内的也可以是两个程序间的。而Android的Parcelable的设计初衷是因为Serializable效率过慢，为了在程序内不同组件间以及不同Android程序间(AIDL)高效的传输数据而设计，这些数据仅在内存中存在，Parcelable是通过IBinder通信的消息的载体。

从上面的设计上我们就可以看出优劣了。

2、效率及选择

Parcelable的性能比Serializable好，在内存开销方面较小，所以在内存间数据传输时推荐使用Parcelable，如activity间传输数据，而Serializable可将数据持久化方便保存，所以在需要保存或网络传输数据时选择Serializable，因为android不同版本Parcelable可能不同，所以不推荐使用Parcelable进行数据持久化

3、编程实现

对于Serializable，类只需要实现Serializable接口，并提供一个序列化版本id(serialVersionUID)即可。而Parcelable则需要实现writeToParcel、describeContents函数以及静态的CREATOR变量，实际上就是将如何打包和解包的工作自己来定义，而序列化的这些操作完全由底层实现。

 4、高级功能上

 Serializable序列化不保存静态变量，可以使用Transient关键字对部分字段不进行序列化，也可以覆盖writeObject、readObject方法以实现序列化过  程自定义

1. 文件目录结构

2. Serializable对象：SerializableObject.java 实现接口Serializable

package com.silion.serializableandparcelable;

import java.io.Serializable;

/**
 * Created by silion on 2015/10/14.
 */
public class SerializableObject implements Serializable {
    private static final long serialVersionUID = 1759681796198207841L;

    private String str;
    private int i;

    public String getStr() {
        return str;
    }

    public void setStr(String str) {
        this.str = str;
    }

    public int getI() {
        return i;
    }

    public void setI(int i) {
        this.i = i;
    }
}

3. Parcelable对象ParcelObject.java 实现接口Parcelable

package com.silion.serializableandparcelable;

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

/**
 * Created by silion on 2015/10/14.
 */
public class ParcelableObject implements Parcelable {
    private String str;
    private int i;

    public String getStr() {
        return str;
    }

    public void setStr(String str) {
        this.str = str;
    }

    public int getI() {
        return i;
    }

    public void setI(int i) {
        this.i = i;
    }

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeString(this.str);
        dest.writeInt(this.i);
    }

    public ParcelableObject() {
    }

    protected ParcelableObject(Parcel in) {
        this.str = in.readString();
        this.i = in.readInt();
    }

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

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

4. activity_main.xml 显示两个分别启动Serializable 和 Parcelable的button

5. activity_second.xml 显示通过Intent传递的对象(通过代码动态添加textview)

6. strings.xml

    SerializableAndParcelable

    Hello world!
    Settings
    Serializable
    Parcelable

7. MainActivity.java 启动Intent传递Serializable和Parcelable对象

package com.silion.serializableandparcelable;

import android.app.Activity;
import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;


public class MainActivity extends Activity implements View.OnClickListener{

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button serializableButton = (Button) findViewById(R.id.serializable);
        serializableButton.setOnClickListener(this);
        Button parcelableButton = (Button) findViewById(R.id.parcelable);
        parcelableButton.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.serializable: {
                serializableMethod();
                break;
            }
            case R.id.parcelable: {
                parcelableMethod();
                break;
            }
            default:
                break;
        }
    }

    public void parcelableMethod() {
        ParcelableObject parcelableObject = new ParcelableObject();
        parcelableObject.setStr("silion - parcelable");
        parcelableObject.setI(0);
        Intent intent = new Intent(this, SecondActivity.class);
        Bundle bundle = new Bundle();
        bundle.putParcelable("parcelable", parcelableObject);
        intent.putExtras(bundle);
        startActivity(intent);
    }

    public void serializableMethod() {
        SerializableObject serializableObject = new SerializableObject();
        serializableObject.setStr("silion - serializable");
        serializableObject.setI(1);
        Intent intent = new Intent(this, SecondActivity.class);
        Bundle bundle = new Bundle();
        bundle.putSerializable("serializable", serializableObject);
        intent.putExtras(bundle);
        startActivity(intent);
    }
}

8. SecondActivity.java 显示Serializable和Parcelable对象

package com.silion.serializableandparcelable;

import android.app.Activity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.widget.LinearLayout;
import android.widget.TextView;

/**
 * Created by silion on 2015/10/14.
 */
public class SecondActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);
        LinearLayout layout = (LinearLayout) findViewById(R.id.contentLayout);
        TextView serializableTextView = new TextView(this);
        TextView parcelableTextView = new TextView(this);
        SerializableObject serializableObject = (SerializableObject) getIntent().getSerializableExtra("serializable");
        ParcelableObject parcelableObject = getIntent().getParcelableExtra("parcelable");
        if (serializableObject != null) {
            serializableTextView.setText("str = " + serializableObject.getStr() + ", i = " + serializableObject.getI());
        }
        if(parcelableObject != null) {
            parcelableTextView.setText("str = " + parcelableObject.getStr() + ", i = " + parcelableObject.getI());
        }
        layout.addView(serializableTextView);
        layout.addView(parcelableTextView);
    }
}

9. manifests 申明Activity