android - How to prevent custom views from losing state across screen orientation changes

Question

I've successfully implemented onRetainNonConfigurationInstance() for my main Activity to save and restore certain critical components across screen orientation changes.

But it seems, my custom views are being re-created from scratch when the orientation changes. This makes sense, although in my case it's inconvenient because the custom view in question is an X/Y plot and the plotted points are stored in the custom view.

Is there a crafty way to implement something similar to onRetainNonConfigurationInstance() for a custom view, or do I need to just implement methods in the custom view which allow me to get and set its "state"?

Answer 1

I think this is a much simpler version. Bundle is a built-in type which implements Parcelable

public class CustomView extends View
{
  private int stuff; // stuff

  @Override
  public Parcelable onSaveInstanceState()
  {
    Bundle bundle = new Bundle();
    bundle.putParcelable("superState", super.onSaveInstanceState());
    bundle.putInt("stuff", this.stuff); // ... save stuff 
    return bundle;
  }

  @Override
  public void onRestoreInstanceState(Parcelable state)
  {
    if (state instanceof Bundle) // implicit null check
    {
      Bundle bundle = (Bundle) state;
      this.stuff = bundle.getInt("stuff"); // ... load stuff
      state = bundle.getParcelable("superState");
    }
    super.onRestoreInstanceState(state);
  }
}