android 开发Parcelable 怎么传值ArrayList

public class TradeEntity implements Parcelable{
    public String id;
    
    //有关进度条的参数
    ArrayList<TradeStateNodeInfo> nodes;
    public TradeEntity() {
        nodes = new ArrayList<TradeStateNodeInfo>();
    }
    /////////////////////////实现parcel接口///////////////////////////////
    @Override
    public int describeContents() {
        return 0;
    }
    @Override
    public void writeToParcel(Parcel out, int arg1) {
        out.writeString(id);
        out.writeList(nodes);
    }
    private TradeEntity(Parcel in)
    {
        id = in.readString();
        nodes = in.readArrayList(TradeStateNodeInfo.class.getClassLoader());
    }
    public static final Parcelable.Creator<TradeEntity> CREATOR = new Parcelable.Creator<TradeEntity>() 
    {
        public TradeEntity createFromParcel(Parcel in) 
        {
            return new TradeEntity(in);
        }

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

 以上问题还会出现不能传值的问题，解决如下：

将 TradeStateNodeInfo 也要实现parcel接口

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

/**
 * 交易状态
 * @author huqiang
 *
 */
public class TradeStateNodeInfo implements Parcelable{

    public int active;   //颜色激活（-1、错误；0、未激活；1、激活；2、当前步骤成功）
    public String time ; 
    public String name ; //节点名称
    
    public TradeStateNodeInfo()
    {}
    private TradeStateNodeInfo(Parcel in)
    {
        active = in.readInt();
        time = in.readString();
        name = in.readString();
    }
    @Override
    public int describeContents() {
        return 0;
    }
    @Override
    public void writeToParcel(Parcel out, int flag) {
        out.writeInt(active);
        out.writeString(time);
        out.writeString(name);
    }
    public static final Parcelable.Creator<TradeStateNodeInfo> CREATOR = new Parcelable.Creator<TradeStateNodeInfo>() 
    {
        public TradeStateNodeInfo createFromParcel(Parcel in) 
        {
            return new TradeStateNodeInfo(in);
        }

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