使用自定义parcelable类在Android应用中解组错误

Question

对于我的Android应用程序,我得到了几个解组错误,尽管我认为我已经完成了通过Parcelables 正确保存和加载对象所需的一切.你能告诉我我的代码有什么问题吗？

错误1:

java.lang.RuntimeException: Unable to start activity ComponentInfo
Caused by: java.lang.RuntimeException: Parcel android.os.Parcel@41279860: Unmarshalling unknown type code 6619241 at offset 1372
at android.os.Parcel.readValue(Parcel.java:1922)
at android.os.Parcel.readMapInternal(Parcel.java:2094)
at android.os.Bundle.unparcel(Bundle.java:223)
at android.os.Bundle.getParcelable(Bundle.java:1158)
at android.app.Activity.onCreate(Activity.java:860)
at my.app.package.PlayComputer.onCreate(PlayComputer.java:1012)
at android.app.Activity.performCreate(Activity.java:4465)

在1012行MyActivity是调用super.onCreate(savedInstanceState);中Activity的onCreate().

protected void onSaveInstanceState(Bundle savedInstanceState) {
    if (myObject == null) {
        savedInstanceState.putParcelable("myObject", null);
    }
    else {
        savedInstanceState.putParcelable("myObject", myObject);
    }
    savedInstanceState.putInt(...);
    savedInstanceState.putString(...);
    savedInstanceState.putBoolean(...);
    super.onSaveInstanceState(savedInstanceState);
}

myObject是一类MyObject具有以下方法:

public void writeToParcel(Parcel out, int flags) {
    out.writeIntArray(...);
    out.writeInt(...);
    out.writeStringArray(...);
    out.writeString(...);
    out.writeParcelableArray(..., flags);
}

public static final Parcelable.Creator<MyObject> CREATOR = new Parcelable.Creator<MyObject>() {
    public MyObject createFromParcel(Parcel in) {
        try {
            if (in == null) {
                return null;
            }
            else {
                return new MyObject(in);
            }
        }
        catch (Exception e) {
            return null;
        }
    }
    public MyObject[] newArray(int size) {
        return new MyObject[size];
    }
};

private MyObject(Parcel in) {
    in.readIntArray(...);
    ... = in.readInt();
    in.readStringArray(...);
    ... = in.readString();
    ... = (OtherObject[]) in.readParcelableArray(OtherObject.class.getClassLoader());
}

错误2:

java.lang.RuntimeException: Unable to start activity ComponentInfo
Caused by: android.os.BadParcelableException: ClassNotFoundException when unmarshalling:
at android.os.Parcel.readParcelable(Parcel.java:1971)
at android.os.Parcel.readValue(Parcel.java:1859)
at android.os.Parcel.readMapInternal(Parcel.java:2099)
at android.os.Bundle.unparcel(Bundle.java:223)
at android.os.Bundle.getParcelable(Bundle.java:1158)
at android.app.Activity.onCreate(Activity.java:905)
at my.app.package.PlayComputer.onCreate(SourceFile:1012)

相同的文件和类.

错误3:

java.lang.RuntimeException: Unable to start activity ComponentInfo
Caused by: java.lang.RuntimeException: Parcel android.os.Parcel@4051aff8: Unmarshalling unknown type code 7340149 at offset 1276
at android.os.Parcel.readValue(Parcel.java:1913)
at android.os.Parcel.readMapInternal(Parcel.java:2083)
at android.os.Bundle.unparcel(Bundle.java:208)
at android.os.Bundle.getParcelable(Bundle.java:1100)
at my.app.package.PlayComputer.onCreate(SourceFile:1111)

这次,引起线(1111)如下:

myObject = (MyObject) savedInstanceState.getParcelable("myObject");

Answer 1

Android有两个不同的类加载器:框架类加载器(它知道如何加载Android类)和APK类加载器(它知道如何加载代码).APK类加载器将框架类加载器设置为其父类,这意味着它还可以加载Android类.

错误#2可能是由Bundle使用框架类加载器引起的,因此它不知道您的类.我认为这可能发生在Android需要保留Bundle并稍后恢复它时(例如在后台内存不足时).您可以通过在捆绑包上设置APK类加载器来解决此问题:

savedInstanceState.setClassLoader(的getClass()getClassLoader());

错误#1和#3更加神秘,您是否可以写入空值writeToParcel()？Android我不太喜欢这样.