Problem in implementing Parcelable containing other Parcelable
I'm implementing Parcelable class that has another Parcelable insde.
In OuterParcelable class:
@Override
public void writeToParcel(Parcel dest, int flags) {
Bundle tmp = new Bundle();
tmp.putParcelable("innerParcelable", mParcelable);
dest.writeBundle(tmp);
and then:
public OuterParcelable(Parcel parcel) {
super();
Bundle b = parcel.readBundle();
mParcelable = b.getParcelable("innerParcelable");
and:
public OuterParcelable createFromParcel(Parcel in) {
return new OuterParcelable(in);
}
When I recreate object using above code I get:
08-18 17:13:08.566: ERROR/AndroidRuntime(15520): Caused by: android.os.BadParcelableException: ClassNotFou开发者_Go百科ndException when unmarshalling: my.package.InnerParcelable
A clean way to store non-primitive attributes as parcelable, possibly null, values. Use Parcel.writeValue() and readValue(). See comments in code below:
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 ...
}
Works like a charm. writeValue() and readValue() encapsulate the dealing with possible nulls and type detection. From 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. ...
Why are you putting the value into a Bundle? Did you completely implement the parcelable in your class?
Parcelable Skeleton
public MyClass(Parcel in) {
readFromParcel(in);
}
//
// Parcelable Implementation
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeParcelable(aParcelableClass, flags);
}
private void writeObject(Parcel dest, Object obj) {
if (obj != null) {
dest.writeInt(1);
dest.writeValue(obj);
} else {
dest.writeInt(0);
}
}
public void readFromParcel(Parcel in) {
aParcelableClass = in.readParcelable(ParcelableClass.class.getClassLoader());
}
private Object readObject(Parcel in) {
Object value = null;
if (in.readInt() == 1) {
value = in.readValue(null); // default classloader
}
return value;
}
public static final Parcelable.Creator<MyClass> CREATOR = new Parcelable.Creator<MyClass>() {
@Override
public MyClass createFromParcel(Parcel source) {
return new MyClass(source);
}
@Override
public MyClass[] newArray(int size) {
return new MyClass[size];
}
};
I added a few things to make null values more easily dealt with, but the principle is the same. You need the @Override items, constructor, and Creator.
If you're going to read and write a parcelable you will have issues if you specify null as the class loader.
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