in android array list is not getting validated

Question

 sbtbtn.setOnClickListener(new View.OnClickListener()

//try to do validate this array list which coming from CustomAdpater if this Array list is empty then code will return and show the Toast but it showing any Toast Data Inserted

                          {
                              @Override
                              public void onClick(View v) {

                                  final String dbName = "/data/data/" + getClass().getPackage().getName() + "/sync.bdb.db";
                                  if (productListAdapter.getList().toString().equals("")) {
                                      Toast.makeText(getApplicationContext(), "Please insert data into list", Toast.LENGTH_SHORT).show();
                                      return;
                                  }
                                  helper.savePurchaseList(productListAdapter.getList(), invoiceNo.getText().toString());
                                  Toast.makeText(getApplicationContext(), "Data Inserted", Toast.LENGTH_SHORT).show();

                              }
                          }

);