问题解编组麻袋

Question

我有几个实现Parcelable的类，其中一些类作为属性相互包含。我正在将这些类编组到一个包裹中，以便在活动之间传递它们。将它们编组到Parcel，但是当我试图解开它们时，我会得到以下错误：

...
AndroidRuntime  E  Caused by: android.os.BadParcelableException: ClassNotFoundException when unmarshalling: schemas.Arrivals.LocationType
AndroidRuntime  E   at android.os.Parcel.readParcelable(Parcel.java:1822)
AndroidRuntime  E   at schemas.Arrivals.LayoverType.<init>(LayoverType.java:121)
AndroidRuntime  E   at schemas.Arrivals.LayoverType.<init>(LayoverType.java:120)
AndroidRuntime  E   at schemas.Arrivals.LayoverType$1.createFromParcel(LayoverType.java:112)
AndroidRuntime  E   at schemas.Arrivals.LayoverType$1.createFromParcel(LayoverType.java:1)
AndroidRuntime  E   at android.os.Parcel.readTypedList(Parcel.java:1509)
AndroidRuntime  E   at schemas.Arrivals.BlockPositionType.<init>(BlockPositionType.java:244)
AndroidRuntime  E   at schemas.Arrivals.BlockPositionType.<init>(BlockPositionType.java:242)
AndroidRuntime  E   at schemas.Arrivals.BlockPositionType$1.createFromParcel(BlockPositionType.java:234)
AndroidRuntime  E   at schemas.Arrivals.BlockPositionType$1.createFromParcel(BlockPositionType.java:1)
...

LayoverType类(失败的地方)：

public class LayoverType implements Parcelable {    
    protected LocationType location;
    protected long start;
    protected long end;

    public LayoverType() {}

    public LocationType getLocation() {
        return location;
    }

    public void setLocation(LocationType value) {
        this.location = value;
    }

    public long getStart() {
        return start;
    }

    public void setStart(long value) {
        this.start = value;
    }

    public long getEnd() {
        return end;
    }

    public void setEnd(long value) {
        this.end = value;
    }


    // **********************************************
    //  for implementing Parcelable
    // **********************************************

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

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeParcelable(location, flags);
        dest.writeLong(start);
        dest.writeLong(end  );
    }

    public static final Parcelable.Creator<LayoverType> CREATOR = new Parcelable.Creator<LayoverType>() {
        public LayoverType createFromParcel(Parcel in) {
            return new LayoverType(in);
        }

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

    private LayoverType(Parcel dest) {
        location = (LocationType) dest.readParcelable(null);    // it's failing here
        start = dest.readLong();
        end   = dest.readLong();
    }
}

下面是LocationType类：

public class LocationType implements Parcelable {
    protected int locid;
    protected String desc;
    protected String dir;
    protected double lat;
    protected double lng;

    public LocationType() {}

    public int getLocid() {
        return locid;
    }

    public void setLocid(int value) {
        this.locid = value;
    }

    public String getDesc() {
        return desc;
    }

    public void setDesc(String value) {
        this.desc = value;
    }

    public String getDir() {
        return dir;
    }

    public void setDir(String value) {
        this.dir = value;
    }

    public double getLat() {
        return lat;
    }

    public void setLat(double value) {
        this.lat = value;
    }

    public double getLng() {
        return lng;
    }

    public void setLng(double value) {
        this.lng = value;
    }

    // **********************************************
    //  for implementing Parcelable
    // **********************************************


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

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeInt   (locid);
        dest.writeString(desc );
        dest.writeString(dir  );
        dest.writeDouble(lat  );
        dest.writeDouble(lng  );
    }

    public static final Parcelable.Creator<LocationType> CREATOR = new Parcelable.Creator<LocationType>() {
        public LocationType createFromParcel(Parcel in) {
            return new LocationType(in);
        }

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

    private LocationType(Parcel dest) {
        locid = dest.readInt   ();
        desc  = dest.readString();
        dir   = dest.readString();
        lat   = dest.readDouble();
        lng   = dest.readDouble();
    }
}

更新2：据我所知，它在以下代码(来自包裹来源)中失败：

Class c = loader == null ? Class.forName(name) : Class.forName(name, true, loader);

为什么找不到这门课？它既存在又实现了Parcelable。

Answer 1

由于“应答”中没有回答这一点，但在评论中，我将发布一个答复:正如@Max指出的那样，您应该使用LocationType.class.getClassLoader()来获得正确的ClassLoader，并消除ClassNotFound异常，即：

in.readParceleable(LocationType.class.getClassLoader());

Answer 2

在下面的设置中，我也遇到了同样的问题:一些处理程序创建了一条消息，并通过Messenger将其发送到远程服务。

这条信息包含了一个包，我把我的可分析的后代放在这里：

final Message msg = Message.obtain(null, 0);
msg.getData().putParcelable("DOWNLOADFILEURLITEM", downloadFileURLItem);

messenger.send(msg);

当远程服务试图打开包裹时，我也有同样的例外。在我的例子中，我曾经监督过远程服务确实是一个单独的os进程。因此，我必须将当前的类加载器设置为服务端的解分段过程使用：

final Bundle bundle = msg.getData();
bundle.setClassLoader(getClassLoader());

DownloadFileURLItem urlItem = (DownloadFileURLItem)
bundle.getParcelable("DOWNLOADFILEURLITEM");

Bundle.setClassLoader设置类加载器，用于加载适当的Parcelable类。在远程服务中，需要将其重置为当前的类加载器。

Answer 3

我发现问题在于我没有将我的应用程序ClassLoader传递给解编组功能：

in.readParceleable(getContext().getClassLoader());

而不是：

in.readParceleable(null); 

或

in.readParceleable(MyClass.class.getClassLoader());