ArrayList → String[]

========== ========== ↑前因↑ 資料取得====== ==========

========== ========== ↓重點↓ ========== ========== 
ArrayList assignCategory = new ArrayList();

assignCategory.add(cursor.getString(1)); 

String[] str = new String[assignCategory.size()];
for (int i=0;i<assignCategory.size();i++)
{
    str[i] = assignCategory.get(i).toString();
}
========== ========== ↑重點↑ ========== ========== 

========== ========== ↓後果↓ 可應用在====== ==========
DialogInterface.OnClickListener di_onclick = new DialogInterface.OnClickListener()
{
    public void onClick(DialogInterface dialog, int which)
    {

    }
};
AlertDialog.Builder mAB = new AlertDialog.Builder(context);
mAB.setItems(str, di_onclick);