Android serializable problem

Question

I created a class, which has several member variables, all of which are serializable... except one Bitmap! I tried to extend bitmap and implement serializable, not thinking

Answer 1

If it is OK to save the bitmap data separately in your application, you can do the following:

In your class that saves the current state, save the bitmap to a folder of your choice:

FileOutputStream out = new FileOutputStream();
bitmap.compress(CompressFormat.PNG, 100, out);

In the class that has the bitmap as member, have the path as the serializable member and reconstruct the bitmap after deserialization:

public class MyClass implements Serializable
{
    // ...
    private String bitmapPath;
    transient Bitmap bitmap;
    // ...

    private void writeObject(ObjectOutputStream out) throws IOException
    {
        out.defaultWriteObject();
    }

    private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException
    {
        in.defaultReadObject();
        bitmap = BitmapFactory.decodeFile(path);
    }

You can implement any other build-up functionality in the readObject() function if needed, since the object is fully constructed after the defaultReadObject() call.

Hope this helps.

BTW, http://developer.android.com/reference/android/os/Parcel.html recommends against using Parcelable for serialization purposes. I do not have enough points yet to leave a comment, so I am editing my own answer to put in this remark.