将可打包对象列表写入可打包对象答案

【问题标题】：Writing a list of parcelable objects to a parcelable object将可打包对象列表写入可打包对象
【发布时间】：2013-11-26 03:42:46
【问题描述】：

我正在尝试将可打包对象的列表写入可打包对象，但我收到一个 java 运行时错误，提示“解组时找不到类...”。

Logcat

11-13 08:41:06.412: E/Parcel(791): Class not found when unmarshalling: com.firstandroidapp.EventMeta
11-13 08:41:06.412: E/Parcel(791): java.lang.ClassNotFoundException: com.firstandroidapp.EventMeta
11-13 08:41:06.412: E/Parcel(791):  at java.lang.Class.classForName(Native Method)
11-13 08:41:06.412: E/Parcel(791):  at java.lang.Class.forName(Class.java:204)
11-13 08:41:06.412: E/Parcel(791):  at java.lang.Class.forName(Class.java:169)
11-13 08:41:06.412: E/Parcel(791):  at android.os.Parcel.readParcelableCreator(Parcel.java:2091)
11-13 08:41:06.412: E/Parcel(791):  at android.os.Parcel.readParcelable(Parcel.java:2055)
11-13 08:41:06.412: E/Parcel(791):  at android.os.Parcel.readValue(Parcel.java:1971)
11-13 08:41:06.412: E/Parcel(791):  at android.os.Parcel.readListInternal(Parcel.java:2264)
11-13 08:41:06.412: E/Parcel(791):  at android.os.Parcel.readList(Parcel.java:1537)
11-13 08:41:06.412: E/Parcel(791):  at com.firstandroidapp.EventHolder.<init>(EventHolder.java:36)
11-13 08:41:06.412: E/Parcel(791):  at com.firstandroidapp.EventHolder$1.createFromParcel(EventHolder.java:17)
11-13 08:41:06.412: E/Parcel(791):  at com.firstandroidapp.EventHolder$1.createFromParcel(EventHolder.java:1)
11-13 08:41:06.412: E/Parcel(791):  at android.os.Parcel.readParcelable(Parcel.java:2062)
11-13 08:41:06.412: E/Parcel(791):  at android.os.Parcel.readValue(Parcel.java:1971)
11-13 08:41:06.412: E/Parcel(791):  at android.os.Parcel.readMapInternal(Parcel.java:2255)
11-13 08:41:06.412: E/Parcel(791):  at android.os.Bundle.unparcel(Bundle.java:223)
11-13 08:41:06.412: E/Parcel(791):  at android.os.Bundle.getParcelable(Bundle.java:1170)
11-13 08:41:06.412: E/Parcel(791):  at android.content.Intent.getParcelableExtra(Intent.java:4501)
11-13 08:41:06.412: E/Parcel(791):  at com.firstandroidapp.AddSubjectFragment.onActivityResult(AddSubjectFragment.java:198)
11-13 08:41:06.412: E/Parcel(791):  at android.support.v4.app.FragmentActivity.onActivityResult(FragmentActivity.java:166)
11-13 08:41:06.412: E/Parcel(791):  at android.app.Activity.dispatchActivityResult(Activity.java:5322)
11-13 08:41:06.412: E/Parcel(791):  at android.app.ActivityThread.deliverResults(ActivityThread.java:3363)
11-13 08:41:06.412: E/Parcel(791):  at android.app.ActivityThread.handleSendResult(ActivityThread.java:3410)
11-13 08:41:06.412: E/Parcel(791):  at android.app.ActivityThread.access$1100(ActivityThread.java:141)
11-13 08:41:06.412: E/Parcel(791):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1304)
11-13 08:41:06.412: E/Parcel(791):  at android.os.Handler.dispatchMessage(Handler.java:99)
11-13 08:41:06.412: E/Parcel(791):  at android.os.Looper.loop(Looper.java:137)
11-13 08:41:06.412: E/Parcel(791):  at android.app.ActivityThread.main(ActivityThread.java:5103)
11-13 08:41:06.412: E/Parcel(791):  at java.lang.reflect.Method.invokeNative(Native Method)
11-13 08:41:06.412: E/Parcel(791):  at java.lang.reflect.Method.invoke(Method.java:525)
11-13 08:41:06.412: E/Parcel(791):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
11-13 08:41:06.412: E/Parcel(791):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
11-13 08:41:06.412: E/Parcel(791):  at dalvik.system.NativeStart.main(Native Method)
11-13 08:41:06.412: E/Parcel(791): Caused by: java.lang.NoClassDefFoundError: com/firstandroidapp/EventMeta
11-13 08:41:06.412: E/Parcel(791):  ... 32 more
11-13 08:41:06.412: E/Parcel(791): Caused by: java.lang.ClassNotFoundException: Didn't find class "com.firstandroidapp.EventMeta" on path: DexPathList[[directory "."],nativeLibraryDirectories=[/system/lib]]
11-13 08:41:06.412: E/Parcel(791):  at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:53)
11-13 08:41:06.412: E/Parcel(791):  at java.lang.ClassLoader.loadClass(ClassLoader.java:501)
11-13 08:41:06.412: E/Parcel(791):  at java.lang.ClassLoader.loadClass(ClassLoader.java:461)
11-13 08:41:06.412: E/Parcel(791):  ... 32 more

据我了解，将EventMeta 的列表写入EventHolder 时发生错误。

这里是EventHolder 和EventMeta 的实现。

事件持有者

public class EventHolder implements Parcelable {

    public List<EventMeta> mEMList = new ArrayList<EventMeta>();
    public Event mEvent;

    @SuppressWarnings("rawtypes")
    public static final Parcelable.Creator CREATOR = new Parcelable.Creator() {
        public EventHolder createFromParcel(Parcel in) {
            return new EventHolder(in); 
        }

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


    public EventHolder(List<EventMeta> mEMList, Event mEvent) {
        this.mEMList = mEMList;
        this.mEvent = mEvent;
    }

    public EventHolder(Parcel in){
        mEMList= new ArrayList<EventMeta>();
        in.readTypedList(mEMList, EventMeta.CREATOR);
        this.mEvent = in.readParcelable(null);
    }

    public int describeContents(){
        return 0;
    }

    public void writeToParcel(Parcel dest, int flags) {
        dest.writeTypedList(mEMList); 
        dest.writeParcelable(mEvent, flags);
    }
}

事件元

public class EventMeta implements Parcelable {

    long mEventMetaId;
    long mEventId;
    Date mStartDate;

    @SuppressWarnings("rawtypes")
    public static final Parcelable.Creator CREATOR = new Parcelable.Creator() {
        public EventMeta createFromParcel(Parcel in) {
            return new EventMeta(in);
        }

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

    public EventMeta(long mEventMetaId, long mEventId, Date mStartDate) {
        this.mEventMetaId = mEventMetaId;
        this.mEventId = mEventId;
        this.mStartDate = mStartDate;
    }

    public EventMeta(Parcel in) {
        this.mEventMetaId = in.readLong();
        this.mEventId = in.readLong();
        this.mStartDate = new Date(in.readLong());
    }

    public int describeContents() {
        return 0;
    }

    public void writeToParcel(Parcel dest, int flags) {
        dest.writeLong(this.mEventMetaId);
        dest.writeLong(this.mEventId);
        dest.writeLong(this.mStartDate.getTime());
    }

}

我的代码有什么问题吗？我在发布之前仔细检查了所有内容，但找不到任何不合适的地方。

更新##

我使用了 daneejela 的答案，现在问题已转移到名为“Class”的类 - 这意味着问题已部分解决。

Class扩展了`Event，它看起来像这样：

public class Class extends Event {  

    long mClassId;
    String mClassLocation;
    long mSubjectId;

    @SuppressWarnings("rawtypes")
    public static final Parcelable.Creator CREATOR = new Parcelable.Creator() {
        public Class createFromParcel(Parcel in) {
            return new Class(in);
        }

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

    public Class(long mClassId, String location, long mSubjectId, long mEventId, int mEventPriority, String mEventTitle, String mEventNotes, long start, long end) {
        super(mEventId, mEventPriority, mEventTitle, mEventNotes, start, end);
        this.mClassId = mClassId;
        this.mClassLocation = location;
        this.mSubjectId = mSubjectId;
    }

    public Class(Parcel in){
        super(in);
        this.mClassId = in.readLong();
        this.mClassLocation = in.readString();
        this.mSubjectId = in.readLong();
    }

    public int describeContents(){
        return 0;
    }

    public void writeToParcel(Parcel dest, int flags) {
        super.writeToParcel(dest, flags);
        dest.writeLong(this.mClassId);
        dest.writeString(this.mClassLocation);
        dest.writeLong(this.mSubjectId);
    }
}

更新 2

事件

public class Event implements Parcelable {

    long mEventId;
    int mEventPriority;
    String mEventTitle;
    String mEventNotes;
    long mEventStartTime;
    long mEventEndTime;

    @SuppressWarnings("rawtypes")
    public static final Parcelable.Creator CREATOR = new Parcelable.Creator() {
        public Event createFromParcel(Parcel in) {
            return new Event(in); 
        }

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

    public Event(long id, int priority, String title, String notes, long start, long end) {
        this.mEventId = id;
        this.mEventPriority = priority;
        this.mEventTitle = title;
        this.mEventNotes = notes;
        this.mEventStartTime = start;
        this.mEventEndTime = end;
    }

    public Event(Parcel in){
        this.mEventId = in.readLong();
        this.mEventPriority = in.readInt();
        this.mEventTitle = in.readString();
        this.mEventNotes = in.readString();
        this.mEventStartTime = in.readLong();
        this.mEventEndTime = in.readLong();
    }

    public int describeContents(){
        return 0;
    }

    public void writeToParcel(Parcel dest, int flags) {
        dest.writeLong(this.mEventId);
        dest.writeInt(this.mEventPriority);
        dest.writeString(this.mEventTitle);
        dest.writeString(this.mEventNotes);
        dest.writeLong(this.mEventStartTime);
        dest.writeLong(this.mEventEndTime);
    }
}

【问题讨论】：

您有什么特别的理由必须使用EventMeta吗？ ArrayList 已经可以打包了。
抱歉，我的意思是EventHolder。 EventMeta 看起来不错，但是在您的 EventHolder 中，编写整个类只是将一个 Event 关联到 EventMetas 的列表感觉有点多余。
嗯..你能发布事件代码吗？（PS 如果您将“public static final Parcelable.Creator CREATOR = new Parcelable.Creator()”更改为“public static final Parcelable.Creator CREATOR = new Parcelable.Creator()”，有什么变化吗？）
@xTCx 性能可能不会成为问题，但如果您打算在活动之间传递这些东西，请注意内存限制！您实际上无法通过 Bundle 放置那么多信息。限制为around 500kB
@xTCx 对不起，是的，我就是这个意思。你应该希望没问题，只要你不包含任何图片。

标签： java android eclipse android-intent parcelable

【解决方案1】：

试试这个代码

公共类 EventHolder 实现 Parcelable { 公共列表 mEMList = new ArrayList(); 公共事件 mEvent；公共静态最终 Parcelable.Creator CREATOR = new Parcelable.Creator() { public EventHolder createFromParcel(Parcel in) { 返回新的 EventHolder(in); } 公共 EventHolder[] newArray(int size) { 返回新的EventHolder[大小]； } }; 公共EventHolder（列表mEMList，事件mEvent）{ this.mEMList = meMList; 这个.mEvent = mEvent; } 公共EventHolder（包裹）{ in.readList(mEMList, mEMList.getClass().getClassLoader()); this.mEvent = in.readParcelable(mEvent.getClass().getClassLoader()); } 公共 int describeContents() { 返回 0XFE； } 公共无效writeToParcel（包裹目的地，int标志）{ dest.writeList(mEMList); dest.writeParcelable(mEvent, describeContents()); } }

我怀疑 Event 是 parcelable 吗？如果不让它成为可包裹的。

【讨论】：

谢谢。 Event 确实可以打包。我已经尝试过您的解决方案，但它不起作用。同样的错误。

【解决方案2】：

你有没有尝试过这个（在 EventHolder 中）：

public class EventHolder implements Parcelable {

//...

public EventHolder(Parcel in){
    mEMList= new ArrayList<EventMeta>();
    in.readTypedList(mEMList, EventMeta.CREATOR);
    this.mEvent = in.readParcelable(null);
}

public int describeContents(){
    return 0;
}

public void writeToParcel(Parcel dest, int flags) {
    dest.writeTypedList(mEMList); 
    dest.writeParcelable(mEvent, flags);
}

}

【讨论】：

谢谢！显然，部分解决了它。问题是现在我得到了同样的错误，但是对于名为Class 的类，它扩展了Event。我正在使用课程代码更新我的主要帖子。你能看看吗？ :D