java.lang.RuntimeException:Parcel android.os.Parcel:解组未知类型代码

Question

我似乎在我的应用程序中遇到一个奇怪的错误(请参阅GitHub),当我将对象传递给实现的不同活动时会发生这种错误Parcelable.

我已经在Stack Overflow上检查了其他问题和答案,但我无法找到解决方案.我在这里尝试了答案,例如 - 这里仅供参考:

-keepclassmembers class * implements android.os.Parcelable {
    static ** CREATOR;
}

我还确保方法调用writeToParcel是有序的.关于此问题的Stack Overflow上的大多数其他问题都没有答案.

此外,我问一个新问题的原因是因为我认为我的问题是由于我在我的应用程序中使用接口的原因引起的(稍后我将对此进行扩展).Stack Overflow上的其他问题不适合我的特定情况.

在下面,我通过GitHub提供了代码的链接,以便您可以根据需要探索更多代码.

---

当我单击按钮以启动新活动(传递实现的对象Parcelable)时,会发生崩溃:

Process: com.satsuware.flashcards, PID: 4664
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.satsuware.flashcards/com.satsumasoftware.flashcards.ui.FlashCardActivity}: java.lang.RuntimeException: Parcel android.os.Parcel@d2219e4: Unmarshalling unknown type code 6815860 at offset 200
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
    ...
 Caused by: java.lang.RuntimeException: Parcel android.os.Parcel@d2219e4: Unmarshalling unknown type code 6815860 at offset 200
at android.os.Parcel.readValue(Parcel.java:2319)
at android.os.Parcel.readListInternal(Parcel.java:2633)
at android.os.Parcel.readArrayList(Parcel.java:1914)
at android.os.Parcel.readValue(Parcel.java:2264)
at android.os.Parcel.readArrayMapInternal(Parcel.java:2592)
at android.os.BaseBundle.unparcel(BaseBundle.java:221)
at android.os.Bundle.getParcelable(Bundle.java:786)
at android.content.Intent.getParcelableExtra(Intent.java:5377)
at com.satsumasoftware.flashcards.ui.FlashCardActivity.onCreate(FlashCardActivity.java:71)
at android.app.Activity.performCreate(Activity.java:6237)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
...

我这样称之为上述活动(另见GitHub):

Intent intent = new Intent(TopicDetailActivity.this, FlashCardActivity.class);
intent.putExtra(FlashCardActivity.EXTRA_TOPIC, mTopic);
intent.putExtra(FlashCardActivity.EXTRA_NUM_CARDS, mSelectedNumCards);
intent.putExtra(FlashCardActivity.EXTRA_CARD_LIST, mFilteredCards);
startActivity(intent);

要考虑的主要部分是我通过时mTopic.这是我创建的Topic 界面.

但是,Topic接口扩展Parcelable,因此实现的对象Topic还包括构造函数,CREATOR字段以及实现的类Parcelable通常必须具有的方法.

您可以通过GitHub链接查看相关的类,但我将在下面提供这些类的相关部分.这是Topic界面:

public interface Topic extends Parcelable {

    int getId();

    String getIdentifier();

    String getName();

    Course getCourse();


    ArrayList<FlashCard> getFlashCards(Context context);


    class FlashCardsRetriever {

        public static ArrayList<FlashCard> filterStandardCards(ArrayList<FlashCard> flashCards, @StandardFlashCard.ContentType int contentType) {
            ArrayList<FlashCard> filteredCards = new ArrayList<>();
            for (FlashCard flashCard : flashCards) {
                boolean isPaper2 = ((StandardFlashCard) flashCard).isPaper2();
                boolean condition;
                switch (contentType) {
                    case StandardFlashCard.PAPER_1:
                        condition = !isPaper2;
                        break;
                    case StandardFlashCard.PAPER_2:
                        condition = isPaper2;
                        break;
                    case StandardFlashCard.ALL:
                        condition = true;
                        break;
                    default:
                        throw new IllegalArgumentException("content type '" + contentType + "' is invalid");
                }
                if (condition) filteredCards.add(flashCard);
            }
            return filteredCards;
        }

        ...
    }

}

一个类(对象)implements Topic:

public class CourseTopic implements Topic {

    ...

    public CourseTopic(int id, String identifier, String name, Course course) {
        ...
    }

    @Override
    public int getId() {
        return mId;
    }

    @Override
    public String getIdentifier() {
        return mIdentifier;
    }

    ...


    protected CourseTopic(Parcel in) {
        mId = in.readInt();
        mIdentifier = in.readString();
        mName = in.readString();
        mCourse = in.readParcelable(Course.class.getClassLoader());
    }

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

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

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

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeInt(mId);
        dest.writeString(mIdentifier);
        dest.writeString(mName);
        dest.writeParcelable(mCourse, flags);
    }

}

在上面代码的最后一行中,您可以看到我传递mCourse,这是Course我创建的对象.这里是:

public class Course implements Parcelable {

    ...

    public Course(String subject, String examBoard, @FlashCard.CourseType String courseType,
              String revisionGuide) {
        ...
    }


    public String getSubjectIdentifier() {
        return mSubjectIdentifier;
    }

    public String getExamBoardIdentifier() {
        return mBoardIdentifier;
    }

    public ArrayList<Topic> getTopics(Context context) {
        ArrayList<Topic> topics = new ArrayList<>();
        String filename = mSubjectIdentifier + "_" + mBoardIdentifier + "_topics.csv";
        CsvParser parser = CsvUtils.getMyParser();
        try {
            List<String[]> allRows = parser.parseAll(context.getAssets().open(filename));
            for (String[] line : allRows) {
                int id = Integer.parseInt(line[0]);
                topics.add(new CourseTopic(id, line[1], line[2], this));
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return topics;
    }

    ...


    protected Course(Parcel in) {
        mSubjectIdentifier = in.readString();
        mBoardIdentifier = in.readString();
        mCourseType = in.readString();
        mRevisionGuide = in.readString();
    }

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

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

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

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeString(mSubjectIdentifier);
        dest.writeString(mBoardIdentifier);
        dest.writeString(mCourseType);
        dest.writeString(mRevisionGuide);
    }

}

我怀疑这里可能会出现问题,这也是我的情景与其他问题不同的原因.

---

说实话,我不确定可能导致错误的原因,因此非常感谢答案中的解释和指导.

---

编辑:

在David Wasser的建议之后,我更新了部分代码:

FlashCardActivity.java - onCreate(...):

Bundle extras = getIntent().getExtras();
extras.setClassLoader(Topic.class.getClassLoader());
mTopic = extras.getParcelable(EXTRA_TOPIC);

Course.java - writeToParcel(...):

dest.writeString(mSubjectIdentifier);
dest.writeString(mBoardIdentifier);
dest.writeString(mCourseType);
dest.writeInt(mRevisionGuide == null ? 0 : 1);
if (mRevisionGuide != null) dest.writeString(mRevisionGuide);

Course.java - Course(Parcel in):

mSubjectIdentifier = in.readString();
mBoardIdentifier = in.readString();
mCourseType = in.readString();
if (in.readInt() != 0) mRevisionGuide = in.readString();

我已经添加了日志消息,Log.d(...)以便在传入时查看是否有任何变量为null,writeToParcel(...)并使用David Wasser的方法来正确处理此问题.

但是,我仍然得到相同的错误消息.

Answer 1

你的问题在于LanguagesFlashCard.以下是您的parcel/unparcel方法:

protected LanguagesFlashCard(Parcel in) {
    mId = in.readInt();
    mEnglish = in.readString();
    mAnswerPrefix = in.readString();
    mAnswer = in.readString();
    mTier = in.readInt();
    mTopic = in.readParcelable(Topic.class.getClassLoader());
}

如您所见,它们不匹配.你写的第二项Parcel是a int,你读的第二项Parcel是a String.

@Override
public void writeToParcel(Parcel dest, int flags) {
    dest.writeInt(mId);
    dest.writeInt(mTier);
    dest.writeString(mEnglish);
    dest.writeString(mAnswerPrefix);
    dest.writeString(mAnswer);
    dest.writeParcelable(mTopic, flags);
}