关於 Parcelable 实作以及继承

看例子

 class Shape implements Parcelable {
   public int left;
   public int top;
   public int width;
   public int height;

   // CREATOR part is omitted

   protected Shape(Parcel in) {
     readFromParcel(in);
   }

   public void readFromParcel(Parcel in) {
     left = in.readInt();
     top = in.readInt();
     width = in.readInt();
     height = in.readInt();
   }

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

   @Override
   public void writeToParcel(Parcel out, int flags) {
     out.writeInt(left);
     out.writeInt(top);
     out.writeInt(width);
     out.writeInt(height);
   }
 }

子类：

 class RoundedRectangle extends Rectangle {
   public int radius;
   // CREATOR part is omitted

   protected RoundedRectangle(Parcel in) {
     super(in);
   }

   public void readFromParcel(Parcel in) {
     super.readFromParcel(in);
     radius = in.readInt();
   }

   @Override
   public void writeToParcel(Parcel out, int flags) {
     super.writeToParcel(out, flags);
     out.writeInt(radius);
   }
 }

注意事项：

• 只有父类需要 implements Parcelable
• 只有父类需要实作 describeContents() 方法
• 如果子类没有增加其他的成员，则可以不用实作那些parceling 的方法
• 写入/读出顺序要写正确。如果父类先写，则父类要先读，如果子类先写，则子类的资料要先读。

参考资料来源：http://idlesun.blogspot.co.il/2012/12/android-parcelable-example-3-subclass