Question

I am rather new at Android and am having some issues in understanding the usage of cwac-MergeAdapter.

I am trying to use MergeAdapter to populate a spinner; my instance of MergeAdapter should include a SimpleCursorAdapter, which is correctly reading data from my db, and (as a footer) a new TextView (or Button) which should be clickable.

Currently, if I feed the spinner the mergeAdapter containing only data from the db, everything works like a charm; however, as I add the new view, I only get a single, blank entry in the whole spinner. Can someone please help me with this?

Here follows the code:

essenceItems = new SimpleCursorAdapter(this, R.layout.db_row_view,
    essenceCursor, from, to);

    TextView addEssence = new TextView(getApplicationContext());
    addEssence.setTextColor(R.color.red);
    addEssence.setText("Add new item...");
    addEssence.setWidth(ViewGroup.LayoutParams.FILL_PARENT);
    addEssence.setHeight(ViewGroup.LayoutParams.WRAP_CONTENT);
    addEssence.setOnClickListener(new OnClickListener() {

       public void onClick(View v) {
         startActivityForResult(new Intent(v.getContext(),
         EssencePopup.class), ADD_ESSENCE);

     }
     });
    ma = new MergeAdapter();
    ma.addAdapter(essenceItems);
    ma.addView(addEssence, true);
    spinner.setAdapter(ma);

Answer 1

It is unlikely that I will ever support adding individual Views to a MergeAdapter to be used in a Spinner. That would imply that I somehow know how to create a drop-down View for some arbitrary View.

The workaround I have for you is for you to add the following to your fork of MergeAdapter:

public View getDropDownView(int position, View convertView, ViewGroup parent) {
  for (ListAdapter piece : pieces) {
    int size = piece.getCount();

    if (position < size) {
      return (((SpinnerAdapter)piece).getDropDownView(position, convertView, parent));
    }

    position -= size;
  }

return (null);
}

Then, instead of adding an individual View via addView(), add your own ArrayAdapter for your additional data. Be sure to call setDropDownViewResource() on all your adapters inside of the MergeAdapter — your sample code never called this, causing some of your other difficulties (e.g., “some entries in the spinner are blank”).

It is possible that I will merge this change into MergeAdapter, or perhaps will create a SpinnerMergeAdapter subclass with it. The blind cast to SpinnerAdapter scares me, which is why I want to ponder this a bit more. In light testing, the code I have above seems to work OK.

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Also, please delete all occurrences of getApplicationContext() from your code, replacing it with this or WhateverYourActivityNameIs.this as appropriate. Only use getApplicationContext() when you know why you are using getApplicationContext().