I'm trying to pass an ArrayList of unknown class type that extend an abstract class, to another activity using Parcelable. Since its not possible to use Parcelable.CREATOR on the abstract class, there is an error when I try to create the ArrayList: in.readTypedList(AbstractChannel.CREATOR), see below:
public class TvNetwork implements Parcelable {
public String name;
public ArrayList<? extends AbstractChannel> mChannels;
public TvNetwork(String name, ArrayList<? extends AbstractChannel> channels) {
this.name = name;
this.mChannels = channels;
}
protected TvNetwork(Parcel in) {
name = in.readString();
mChannels = in.readTypedList(AbstractChannel.CREATOR); // here is the error
}
public static final Creator<TvNetwork> CREATOR = new Creator<TvNetwork>() {
#Override
public TvNetwork createFromParcel(Parcel in) {
return new TvNetwork(in);
}
#Override
public TvNetwork[] newArray(int size) {
return new TvNetwork[size];
}
};
public ArrayList<? extends AbstractChannel> getChannels() {
return mChannels;
}
#Override
public int describeContents() {
return 0;
}
#Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeString(name);
dest.writeTypedList(mChannels);
}
}
Writing seems to work but not reading. This obviously does not work either, but explains a bit more what I want to do:
in.readTypedList(mChannels, <? extends AbstractChannel>.class.getClassLoader());
Any ideas?
I want to convert this generic class to a parcelable object, but I don't have very clear the concepts of the issue.
Class:
public class Type<T> implements Parcelable {
// T stands for "Type"
private T t;
public void set(T t) { this.t = t; }
public T get() { return t; }
}
This is what I've tried,. but I know that this is not correct, or maybe this is not complete.
public class Type<T> implements Parcelable {
// T stands for "Type"
private T t;
protected Type(Parcel in) {
}
public void set(T t) { this.t = t; }
public T get() { return t; }
#Override
public int describeContents() {
return 0;
}
#Override
public void writeToParcel(Parcel dest, int flags) {
}
public static final Creator< Type > CREATOR = new Creator< Type >() {
#Override
public Type createFromParcel(Parcel in) {
return new Type(in);
}
#Override
public Type[] newArray(int size) {
return new Type[size];
}
};
}
This is similar approach as vikas kumar but guarantte that you can pass only Parcelable as T parameter so you avoid exception.
public class Type<T extends Parcelable> implements Parcelable {
private T t;
protected Type(Parcel in) {
t = (T) in.readValue(t.getClass().getClassLoader());
}
public static final Creator<Type> CREATOR = new Creator<Type>() {
#Override
public Type createFromParcel(Parcel in) {
return new Type(in);
}
#Override
public Type[] newArray(int size) {
return new Type[size];
}
};
#Override
public int describeContents() {
return 0;
}
#Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeValue(t);
}
}
Your generic data type may cause runtime error
so make sure you implements Parcelable and also the class you are passing should implement Parcelable otherwise it will cause runtime error.
public class Type<T extends Parcelable> implements Parcelable {
// T stands for "Type"
private T t;
public void set(T t) { this.t = t; }
public T get() { return t; }
protected Type(Parcel in) {
final String className = in.readString();
try {
t = in.readParcelable(Class.forName(className).getClassLoader());
} catch (ClassNotFoundException e) {
Log.e("readParcelable", className, e);
}
}
#Override
public int describeContents() {
return 0;
}
#Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeValue(t);
}
#SuppressWarnings("unused")
public static final Parcelable.Creator<Type> CREATOR = new Parcelable.Creator<Type>() {
#Override
public Type createFromParcel(Parcel in) {
return new Type(in);
}
#Override
public Type[] newArray(int size) {
return new Type[size];
}
};
}
Below are my code snippet for using WritableComparator, but it does not work
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.io.WritableComparator;
public class MovieComparator extends WritableComparator{
public MovieComparator(){
super(Movie.class);
}
#Override
public int compare(WritableComparable o,WritableComparable o2){
System.out.println("in compare");
Movie m = (Movie)o;
Movie m2 = (Movie)o2;
System.out.println(m.compareTo(m2));
return m.movieId.compareTo(m2.movieId);
}
}
public class Movie implements WritableComparable {
Text movieId;
Text movieTitle;
public Movie(Text movieId, Text movieTitle) {
this.movieId = movieId;
this.movieTitle = movieTitle;
}
public Movie(){
}
public String getMovieId() {
return movieId.toString();
}
public void setMovieId(String movieId) {
this.movieId = new Text(movieId);
}
public String getMovieTitle() {
return movieTitle.toString();
}
public void setMovieTitle(String movieTitle) {
this.movieTitle = new Text(movieTitle);
}
#Override
public void readFields(DataInput in) throws IOException {
//movieId = in.read;
movieId.readFields(in);
movieTitle.readFields(in);
}
#Override
public void write(DataOutput out) throws IOException {
//out.writeUTF(movieId);
//out.writeUTF(movieTitle);
movieId.write(out);
movieTitle.write(out);
}
#Override
public int compareTo(Movie o) {
// System.out.println("in compareTo");
int res=movieTitle.compareTo(o.movieTitle);
return res;
}
#Override
public int hashCode(){
return movieId.hashCode();
}
#Override
public boolean equals(Object o){
Movie m=(Movie)o;
return movieId.equals(m.movieId);
}
#Override
public String toString(){
return movieTitle.toString();
}
}
In driver class I am setting the comparator by below line
job.setSortComparatorClass(MovieComparator.class);
Can any body tell me where I am wrong in this at it gives exception below
14/09/08 14:17:03 WARN mapred.LocalJobRunner: job_local_0001
java.io.IOException: Spill failed
at org.apache.hadoop.mapred.MapTask$MapOutputBuffer.collect(MapTask.java:1029)
at org.apache.hadoop.mapred.MapTask$NewOutputCollector.write(MapTask.java:691)
at org.apache.hadoop.mapreduce.TaskInputOutputContext.write(TaskInputOutputContext.java:80)
at com.impetus.MovieMapper.map(MovieMapper.java:44)
at com.impetus.MovieMapper.map(MovieMapper.java:1)
at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:764)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:370)
at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:212)
I found the issue that Instead of using super(Movie.class), I will have to use super(Movie.class,true). As by sending true, WritableComparator will instantiate the object other wise it will pass null in compare method
I am working on an Android App, and I am trying to pass information using Parcelable. So here's what I've got.
import android.os.Parcel;
import android.os.Parcelable;
abstract class Role implements Parcelable {
private String name;
private String image;
public Role() {
}
public Role(Parcel read) {
name = read.readString();
image = read.readString();
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getImage() {
return image;
}
public void setImage(String image) {
this.image = image;
}
public String toString() {
return this.name;
}
public static final Parcelable.Creator<Role> CREATOR =
new Parcelable.Creator<Role>() {
public Role createFromParcel(Parcel source) {
return new Role(source);
}
public Role[] newArray(int size) {
return new Role[size];
}
};
public int describeContents() {
// TODO Auto-generated method stub
return 0;
}
public void writeToParcel(Parcel dest, int flags) {
// TODO Auto-generated method stub
dest.writeString(name);
dest.writeString(image);
}
}
However, when I try to compile I get the Error (where I placed the comment)
Cannot instantiate the Type Role
Any thoughts on this?
Best regards
I have not used parcelable in abstract class myself, but it should be ok. You may want to check here or more generally here
I have a VERY similar class (two strings) but its a public static class.
I do new() on my string members in the constructor.
Yout class Role is defined as abstract, the abstract classes cannot be instantiated.
just define your class Role:
class Role implements Parcelable {
//...
}
As qjuanp mentioned, one cannot instantiate an abstract class (as per Java's and common OOP definition; you cannot instantiate something that is abstract, it has got to be more defined).
I'm sure you're trying to use some subclasses of Role (that's about the only way you can use both abstract and implement Parcelable here), consider using this approach:
public abstract class A implements Parcelable {
private int a;
protected A(int a) {
this.a = a;
}
public void writeToParcel(Parcel out, int flags) {
out.writeInt(a);
}
protected A(Parcel in) {
a = in.readInt();
}
}
public class B extends A {
private int b;
public B(int a, int b) {
super(a);
this.b = b;
}
public static final Parcelable.Creator<B> CREATOR = new Parcelable.Creator<B>() {
public B createFromParcel(Parcel in) {
return new B(in);
}
public B[] newArray(int size) {
return new B[size];
}
};
public int describeContents() {
return 0;
}
public void writeToParcel(Parcel out, int flags) {
super.writeToParcel(out, flags);
out.writeInt(b);
}
private B(Parcel in) {
super(in);
b = in.readInt();
}
}
I've got a few classes that implement Parcelable and some of these classes contain each other as properties. I'm marshalling the classes into a Parcel to pass them between activities. Marshalling them TO the Parcel works fine, but when I try to unmarshall them I get the following error:
...
AndroidRuntime E Caused by: android.os.BadParcelableException: ClassNotFoundException when unmarshalling: schemas.Arrivals.LocationType
AndroidRuntime E at android.os.Parcel.readParcelable(Parcel.java:1822)
AndroidRuntime E at schemas.Arrivals.LayoverType.<init>(LayoverType.java:121)
AndroidRuntime E at schemas.Arrivals.LayoverType.<init>(LayoverType.java:120)
AndroidRuntime E at schemas.Arrivals.LayoverType$1.createFromParcel(LayoverType.java:112)
AndroidRuntime E at schemas.Arrivals.LayoverType$1.createFromParcel(LayoverType.java:1)
AndroidRuntime E at android.os.Parcel.readTypedList(Parcel.java:1509)
AndroidRuntime E at schemas.Arrivals.BlockPositionType.<init>(BlockPositionType.java:244)
AndroidRuntime E at schemas.Arrivals.BlockPositionType.<init>(BlockPositionType.java:242)
AndroidRuntime E at schemas.Arrivals.BlockPositionType$1.createFromParcel(BlockPositionType.java:234)
AndroidRuntime E at schemas.Arrivals.BlockPositionType$1.createFromParcel(BlockPositionType.java:1)
...
The LayoverType class (where it's failing):
public class LayoverType implements Parcelable {
protected LocationType location;
protected long start;
protected long end;
public LayoverType() {}
public LocationType getLocation() {
return location;
}
public void setLocation(LocationType value) {
this.location = value;
}
public long getStart() {
return start;
}
public void setStart(long value) {
this.start = value;
}
public long getEnd() {
return end;
}
public void setEnd(long value) {
this.end = value;
}
// **********************************************
// for implementing Parcelable
// **********************************************
#Override
public int describeContents() {
return 0;
}
#Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeParcelable(location, flags);
dest.writeLong(start);
dest.writeLong(end );
}
public static final Parcelable.Creator<LayoverType> CREATOR = new Parcelable.Creator<LayoverType>() {
public LayoverType createFromParcel(Parcel in) {
return new LayoverType(in);
}
public LayoverType[] newArray(int size) {
return new LayoverType[size];
}
};
private LayoverType(Parcel dest) {
location = (LocationType) dest.readParcelable(null); // it's failing here
start = dest.readLong();
end = dest.readLong();
}
}
Here's the LocationType class:
public class LocationType implements Parcelable {
protected int locid;
protected String desc;
protected String dir;
protected double lat;
protected double lng;
public LocationType() {}
public int getLocid() {
return locid;
}
public void setLocid(int value) {
this.locid = value;
}
public String getDesc() {
return desc;
}
public void setDesc(String value) {
this.desc = value;
}
public String getDir() {
return dir;
}
public void setDir(String value) {
this.dir = value;
}
public double getLat() {
return lat;
}
public void setLat(double value) {
this.lat = value;
}
public double getLng() {
return lng;
}
public void setLng(double value) {
this.lng = value;
}
// **********************************************
// for implementing Parcelable
// **********************************************
#Override
public int describeContents() {
return 0;
}
#Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeInt (locid);
dest.writeString(desc );
dest.writeString(dir );
dest.writeDouble(lat );
dest.writeDouble(lng );
}
public static final Parcelable.Creator<LocationType> CREATOR = new Parcelable.Creator<LocationType>() {
public LocationType createFromParcel(Parcel in) {
return new LocationType(in);
}
public LocationType[] newArray(int size) {
return new LocationType[size];
}
};
private LocationType(Parcel dest) {
locid = dest.readInt ();
desc = dest.readString();
dir = dest.readString();
lat = dest.readDouble();
lng = dest.readDouble();
}
}
Update 2: As far as I can tell it's failing at the following bit of code (from Parcel's source):
Class c = loader == null ? Class.forName(name) : Class.forName(name, true, loader);
Why is it not able to find the class? It both exists and implements Parcelable.
Because this was not answered in "answer" but in comment I will post an answer:
As #Max-Gontar pointed you should use LocationType.class.getClassLoader() to get the correct ClassLoader and get rid of ClassNotFound exception, i.e.:
in.readParceleable(LocationType.class.getClassLoader());
I had the same problem with the following setup: some handler creates a Message and sends its over a Messenger to a remote service.
the Message contains a Bundle where I put my Parcelable descendant:
final Message msg = Message.obtain(null, 0);
msg.getData().putParcelable("DOWNLOADFILEURLITEM", downloadFileURLItem);
messenger.send(msg);
I had the same exception when the remote service tried to unparcel. In my case, I had overseen that the remote service is indeed a separate os process. Therefore, I had to set the current classloader to be used by the unparcelling process on the service side:
final Bundle bundle = msg.getData();
bundle.setClassLoader(getClassLoader());
DownloadFileURLItem urlItem = (DownloadFileURLItem)
bundle.getParcelable("DOWNLOADFILEURLITEM");
Bundle.setClassLoader sets the classloader which is used to load the appropriate Parcelable classes. In a remote service, you need to reset it to the current class loader.
I found the problem was I was not passing my applications ClassLoader to the unmarshalling function:
in.readParceleable(getContext().getClassLoader());
Rather than:
in.readParceleable(null);
OR
in.readParceleable(MyClass.class.getClassLoader());
Just adding my 2 cents here, because I lost more than half a day scratching my head on this. You might get this error if you don't put the writes methods and reads methods in the exact same order. For instance the following would be wrong:
#Override
// Order: locid -> desc -> lat -> dir -> lng
public void writeToParcel(Parcel dest, int flags) {
dest.writeInt (locid);
dest.writeString(desc);
dest.writeDouble(lat);
dest.writeString(dir);
dest.writeDouble(lng);
}
// Order: locid -> desc -> dir -> lat -> lng
private LocationType(Parcel dest) {
locid = dest.readInt();
desc = dest.readString();
dir = dest.readString();
lat = dest.readDouble();
lng = dest.readDouble();
}
By the way the author did this correctly but it might help someone one day.
I am not very familiar with Parcelable but if it's anything like Serialization each call to write an object that implements the interface will cause a recursive call to writeToParcel(). Therefore, if something along the call stack fails or writes a null value the class that initiated the call may not be constructed correctly.
Try:
Trace the writeToParcel() call stack through all the classes starting at the first call to writeToParcel() and verify that all the values are getting sent correctly.
I got ClassNotFoundException too and posting my solution bc the answers here led me to the right direction. My scenario is that I have nested parcelable objects. Object A contains an ArrayList of Object's B. Both implement Parcelable.
Writing the list of B Object's in class A:
#Override
public void writeToParcel(Parcel dest, int flags) {
...
dest.writeList(getMyArrayList());
}
Reading the list in class A:
public ObjectA(Parcel source) {
...
myArrayList= new ArrayList<B>();
source.readList(myArrayList, B.class.getClassLoader());
}
Thank you!
Instead of using writeParcelable and readParcelable use writeToParcel and createFromParcel directly. So the better code is:
#Override
public void writeToParcel(Parcel dest, int flags) {
location.writeToParcel(dest, flags);
dest.writeLong(start);
dest.writeLong(end );
}
public static final Parcelable.Creator<LayoverType> CREATOR = new Parcelable.Creator<LayoverType>() {
public LayoverType createFromParcel(Parcel in) {
return new LayoverType(in);
}
public LayoverType[] newArray(int size) {
return new LayoverType[size];
}
};
private LayoverType(Parcel dest) {
location = LocationType.CREATOR.createFromParcel(dest);
start = dest.readLong();
end = dest.readLong();
}
Well I had the same problem and solve it in a very silly way that I dont know if its called a solution at all.
lets say you have this class you want to pass to another activity
public class Person implements Parcelable,Serializable{
public String Name;
public int Age;
#Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeString(name);
dest.writeInt(age);
}
public SeriesInfo(Parcel in) {
age= in.readInt(); //her was my problem as I have put age befor name
//while in the writeToParcel function I have defined
//dest.writeInt(age) after in.readString();???!!!!
name= in.readString();
}
}
Thats it When I changed the:
dest.writeString(name);
dest.writeInt(age);
to
dest.writeInt(age);
dest.writeString(name);
The problem was solved???!!!!
If you have an Object with a property of type of List objects you should pass the class loader when you read the property for example:
public class Mall implements Parcelable {
public List<Outstanding> getOutstanding() {
return outstanding;
}
public void setOutstanding(List<Outstanding> outstanding) {
this.outstanding = outstanding;
}
protected Mall(Parcel in) {
outstanding = new ArrayList<Outstanding>();
//this is the key, pass the class loader
in.readList(outstanding, Outstanding.class.getClassLoader());
}
#Override
public int describeContents() {
return 0;
}
#Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeList(outstanding);
}
public static final Parcelable.Creator<Mall> CREATOR = new Parcelable.Creator<Mall>() {
public Mall createFromParcel(Parcel in) {
return new Mall(in);
}
public Mall[] newArray(int size) {
return new Mall[size];
}
};
}
Note: Is important that the class Outstanding implements the Parceable interface.
I got this exception because I was missing a constructor. The same must be done for all classes that implement Parcelable:
// add new constructor
#RequiresApi(Build.VERSION_CODES.N)
private LocationType(Parcel dest, ClassLoader loader) {
super(dest, loader);
locid = dest.readInt();
desc = dest.readString();
dir = dest.readString();
lat = dest.readDouble();
lng = dest.readDouble();
}
public static final Creator<LayoverType> CREATOR = new ClassLoaderCreator<LayoverType>() {
// add createFromParcel method with ClassLoader
#Override
public LayoverType createFromParcel(Parcel in, ClassLoader loader)
{
return Build.VERSION.SDK_INT >= Build.VERSION_CODES.N ? new LayoverType(in, loader) : new LayoverType(in);
}
public LayoverType createFromParcel(Parcel in) {
// call other createFromParcel method.
return createFromParcel(in, null);
}
public LayoverType[] newArray(int size) {
return new LayoverType[size];
}
};