java - Is not accessible in current context

Question

I have the following code

public abstract class BaseAdapter<T, V extends BaseAdapter.ViewHolder> extends ArrayAdapter<T> {
    public BaseAdapter(Context context, int resource, Collection<T> collection) {
        // typical constructor logic
    }

    // some other custom defined methods

    public static class ViewHolder {
        // custom defined logic
    }
}

public class ModelAdapter extends BaseAdapter<Model, ModelAdapter.ModelViewHolder> {
    public ModelAdapter(Context context, int resource, Collection<Model> collection) {
       super(context, resource, collection);
       // typical constructor logic
    }

    public static class ModelViewHolder extends ViewHolder {
        // custom defined logic
    }
}

The BaseAdapter and ModelAdapter are in separated files. The problem is that I have a compilation error when trying to define the ModelAdapter: ModelViewHolder is not accessible in current context

I don't really understand this error and can't figure out what I am doing wrong. Can somebody explain to me this problem or a link that may clarify this situation?

Answer 1

Creation Dead Lock

You use ModelAdapter.ModelViewHolder as the template parameter of BaseAdapter, and let ModelAdapter extends BaseAdapter, then the compiler tried to create ModelViewHolder first, but the class of ModelAdapter.ModelViewHolder(the type is Class) is not yet created. It must wait for ModelAdapter to be created, because ModelViewHolder is in the scope of ModelAdapter.

The way to solve it is put the ModelViewHolder class into a new *.java file.