Question

我有一些实现Parcelable的类，其中一些类作为属性互相包含。我正在将类编组为Parcel以在活动之间传递它们。将它们编组到包裹中工作正常，但是当我尝试解组它们时，我收到以下错误：

...
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();
    }
}

这是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，它在以下位代码（来自Parcel's source）失败了：

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

为什么找不到课程？它既存在又实现Parcelable。

Answer 1

因为在“回答”中没有回答，但在评论中我会发回答：正如@ Max-Gontar指出的那样，你应该使用LocationType.class.getClassLoader（）来获取正确的ClassLoader并摆脱ClassNotFound异常，即：

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

Answer 2

我在以下设置中遇到了同样的问题：某个处理程序创建了一个Message并通过Messenger将其发送到远程服务。

消息包含一个Bundle，我放置了我的Parcelable后代：

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

messenger.send(msg);

当远程服务尝试取消选中时，我遇到了同样的异常。在我的情况下，我监督了远程服务确实是一个单独的操作系统进程。因此，我必须设置当前的类加载器以供服务端的取消分析过程使用：

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

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

Bundle.setClassLoader设置用于加载相应Parcelable类的类加载器。在远程服务中，您需要将其重置为当前的类加载器。

Answer 3

我发现问题是我没有将我的应用程序ClassLoader传递给解组函数：

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

而不是：

in.readParceleable(null);

OR

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

Answer 4

在这里加上我的2美分，因为我失去了半天的时间。如果不以完全相同的顺序放置写入方法和读取方法，则可能会出现此错误。例如，以下是错误的：

 @Override
    // Order: locid -> desc -> lat -> dir -> lng
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeInt   (locid);
        dest.writeString(desc);
        dest.writeDouble(lat);
        dest.writeString(dir);
        dest.writeDouble(lng);
    }
    // Order: locid -> desc -> dir -> lat -> lng
    private LocationType(Parcel dest) {
        locid = dest.readInt();
        desc  = dest.readString();
        dir   = dest.readString();
        lat   = dest.readDouble();
        lng   = dest.readDouble();
    }

顺便提一下，作者这样做了，但有一天它可能对某人有所帮助。

Answer 5

我对Parcelable不是很熟悉，但是如果它类似于Serialization，那么每次调用写一个实现该接口的对象都会导致对writeToParcel（）的递归调用。因此，如果调用堆栈中的某些内容失败或写入空值，则可能无法正确构造发起调用的类。

尝试：跟踪writeToParcel（）调用堆栈，通过从第一次调用writeToParcel（）开始的所有类，并验证是否正确发送了所有值。

Answer 6

我也得到了ClassNotFoundException并且在这里发布了我的解决方案答案，这使我找到了正确的方向。我的情况是我有嵌套的parcelable对象。对象A包含Object B的ArrayList。两者都实现了Parcelable。在A类中编写B对象列表：

@Override
public void writeToParcel(Parcel dest, int flags) {
    ...
    dest.writeList(getMyArrayList());

}

阅读A类中的清单：

public ObjectA(Parcel source) {
    ...
    myArrayList= new ArrayList<B>();
    source.readList(myArrayList, B.class.getClassLoader());
}

谢谢！

Answer 7

而不是使用writeParcelable和readParcelable直接使用writeToParcel和createFromParcel。所以更好的代码是：

@Override
public void writeToParcel(Parcel dest, int flags) {
    location.writeToParcel(dest, 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.CREATOR.createFromParcel(dest);
    start = dest.readLong();
    end   = dest.readLong();
}

Answer 8

我有同样的问题并以非常愚蠢的方式解决它，我不知道它是否完全被称为解决方案。

假设您要将此课程传递给其他活动

public class Person implements  Parcelable,Serializable{
public  String Name;
public  int Age;

@Override
public void writeToParcel(Parcel dest, int flags) {

 dest.writeString(name);
dest.writeInt(age);

}

public SeriesInfo(Parcel in) {

age= in.readInt(); //her was my problem as I have put age befor name
//while in the writeToParcel function I have defined
//dest.writeInt(age) after  in.readString();???!!!!
name= in.readString();

}
}

多数民众赞成当我改变了：

dest.writeString(name);
dest.writeInt(age);

到

dest.writeInt(age);
dest.writeString(name);

问题解决了??? !!!!

Answer 9

如果你有一个具有List对象类型属性的Object，你应该在读取属性时传递类加载器，例如：

public class Mall implements Parcelable {

    public List<Outstanding> getOutstanding() {
        return outstanding;
    }

    public void setOutstanding(List<Outstanding> outstanding) {
        this.outstanding = outstanding;
    }        

    protected Mall(Parcel in) {
        outstanding = new ArrayList<Outstanding>();
        //this is the key, pass the class loader
        in.readList(outstanding, Outstanding.class.getClassLoader());
    }

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

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeList(outstanding);
    }

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

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

注意：Outstanding类实现Parceable接口很重要。

Answer 10

由于缺少构造函数，因此出现了此异常。所有实现Parcelable的类都必须执行相同的操作：

// add new constructor
@RequiresApi(Build.VERSION_CODES.N)
private LocationType(Parcel dest, ClassLoader loader) {
    super(dest, loader);
    locid = dest.readInt();
    desc  = dest.readString();
    dir   = dest.readString();
    lat   = dest.readDouble();
    lng   = dest.readDouble();
}

public static final Creator<LayoverType> CREATOR = new ClassLoaderCreator<LayoverType>() {

    // add createFromParcel method with ClassLoader
    @Override
    public LayoverType createFromParcel(Parcel in, ClassLoader loader)
    {
        return Build.VERSION.SDK_INT >= Build.VERSION_CODES.N ? new LayoverType(in, loader) : new LayoverType(in);
    }

    public LayoverType createFromParcel(Parcel in) {
        // call other createFromParcel method.    
        return createFromParcel(in, null);
    }

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

问题解组parcelables

10 个答案: