android序列化(2)Parcelable与Parcel

1.简介

Parcel  ：　　包裹

　　Android采用这个它封装消息数据。这个是通过IBinder通信的消息的载体。需要明确的是Parcel用来存放数据的是内存（RAM），而不是永久性介质（Nand等）。

Parcelable：　可放入包裹的协议接口

　　如果需要封装到包裹中去，就必须实现这一接口，实现了这一接口，该实体就成为“可打包的”了。

2.示例

 import android.content.Intent;
 import android.os.Parcel;
 import android.os.Parcelable;

 import com.e.weixin.R;
 import com.e.weixin.contacts.beans.ContactBean;

 public class MsgBean implements Parcelable{

     public static final int MSB_TYPE_TXT = ;
     public static final int MSB_TYPE_TP = ;
     public static final int MSB_TYPE_XSP = ;
     public static final int MSB_TYPE_HB = ;
     public static final int MSB_TYPE_ZZ = ;
     public static final int MSB_TYPE_SC = ;
     public static final int MSB_TYPE_WZ = ;
     public static final int MSB_TYPE_SPLT = ;
     public static final int MSB_TYPE_MP = ;
     public static final int MSB_TYPE_YY = ;

     ContactBean contact;
     public int type ;
     public String title;
     public String content;
     public int icon;
     public int movie_res;

     //==================
     public MsgBean(){

     }

     //下面代码都是as自动生成
     protected MsgBean(Parcel in) {
         //从Parcel中读一个实现了Parcelable接口的自定义的类，需要ClassLoader
         contact = in.readParcelable(ContactBean.class.getClassLoader());
         type = in.readInt();
         title = in.readString();
         content = in.readString();
         icon = in.readInt();
         movie_res = in.readInt();
     }

     public static final Creator<MsgBean> CREATOR = new Creator<MsgBean>() {
         @Override
         public MsgBean createFromParcel(Parcel in) {
             return new MsgBean(in);
         }

         @Override
         public MsgBean[] newArray(int size) {
             return new MsgBean[size];
         }
     };

     @Override
     public int describeContents() {
         return ;
     }

     @Override
     public void writeToParcel(Parcel dest, int flags) {
         dest.writeParcelable(contact,flags);//写另一个自定义的类，它也实现了Parcelable接口
         dest.writeInt(type);
         dest.writeString(title);
         dest.writeString(content);
         dest.writeInt(icon);
         dest.writeInt(movie_res);
     }

     public static void test(){

         int sz = -,position = -;
         //1,准备一个Parcel,其它数据放入其中
         Parcel parcel = Parcel.obtain();
         sz = parcel.dataSize();
         position = parcel.dataPosition();

         //2,准备要写入的对象，其中包含另一个实现了Parcelable的对象
         ContactBean cb = new ContactBean();
         cb.name = "name";
         cb.sectionCount = ;
         cb.isSection = true;
         cb.icon = R.drawable.ebf;

         MsgBean mb1 = new MsgBean();
         mb1.type = ;
         mb1.icon = R.drawable.ebf;
         mb1.content = "content";
         mb1.title = "title";
         mb1.contact = cb;
         mb1.movie_res = R.raw.movie;

         //3,写入
         mb1.writeToParcel(parcel,);
         sz = parcel.dataSize();
         position = parcel.dataPosition();

         //4,读取
         MsgBean mb2 = MsgBean.CREATOR.createFromParcel(parcel);

         MsgBean mb3 = parcel.readParcelable(MsgBean.class.getClassLoader());

         parcel.writeParcelable(mb1, );

         MsgBean mb4 = MsgBean.CREATOR.createFromParcel(parcel);
         MsgBean mb5 = parcel.readParcelable(MsgBean.class.getClassLoader());

         //5,开始序列
         Intent intent = new Intent();
         intent.putExtra("parcelable",mb1);
         intent.putExtra("int",);

         //6,开始反序列
         //通常是在另一个地方得到上面的Intent
         MsgBean mb6 = intent.getParcelableExtra("parcelable");
         int data = intent.getIntExtra("int",-);
     }
 }