android - 实现包含其他 Parcelable 的 Parcelable 时出现问题

Question

我正在实现具有另一个 Parcelable insde 的 Parcelable 类。

在 OuterParcelable 类中:

@Override
public void writeToParcel(Parcel dest, int flags) {
    Bundle tmp = new Bundle();

    tmp.putParcelable("innerParcelable", mParcelable);
    dest.writeBundle(tmp);

然后:

public OuterParcelable(Parcel parcel) {
    super();

    Bundle b = parcel.readBundle();
    mParcelable = b.getParcelable("innerParcelable");

和:

    public OuterParcelable createFromParcel(Parcel in) {
        return new OuterParcelable(in);
    }

当我使用上面的代码重新创建对象时，我得到:

 08-18 17:13:08.566: ERROR/AndroidRuntime(15520): Caused by: android.os.BadParcelableException: ClassNotFoundException when unmarshalling: my.package.InnerParcelable

Answer 1

一种将非原始属性存储为可分割的、可能为空的值的简洁方法。使用 Parcel.writeValue()和 readValue() .请参阅下面代码中的注释:

public class MyParcelableClass implements Parcelable {
    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeValue(getIntegerAttribute()); // getIntegerAttribute() returns Integer
        dest.writeValue(getDoubleAttribute());
        dest.writeValue(getMyEnumAttribute()); // getMyEnumAttribute() returns a user defined enum
        dest.wrtieValue(getUserClassAttribute()); //UserClass must implement Parcelable in a similar fashion
    }

    private MyParcelableClass(Parcel in) {
        setIntegerAttribute((Integer)in.readValue(null)); //pass null to use default class loader. Ok for Integer, String, etc.
        setDoubleAttribute((Double)in.readValue(null)); //Cast to your specific attribute type
        setEnumAttribute((MyEnum)in.readValue(null));
        setUserClassAttribute((UserClass)in.readValue(UserClass.class.getClassLoader())); //Use specific class loader
    }

    @Override
    public int describeContents() ...

    public static final Parcelable.Creator<ParcelableLocationBean> CREATOR ...    
}

像魅力一样工作。 writeValue() 和 readValue() 封装了可能的空值处理和类型检测。来自 javadoc:

public final void writeValue (Object v)
Flatten a generic object in to a parcel. The given Object value may currently be one of the following types:
null, String, Integer, ...
String[], boolean[], ...
Any object that implements the Parcelable protocol. ...