Android: onclicklistener forced close?

Question

Without the onclick listener implements and its relevant codes, the activity works fine. But when onclick listener is there it just force close.

Here is my code:

public class Names extends ListActivity implements OnClickListener {
    private static String[] FROM = { _ID, NAME, ADDRESS, AGE };
       private static int[] TO = { R.id.rowid, R.id.name, R.id.address, R.id.age};
       private static String ORDER_BY = NAME + " DESC";


       @Override
       public void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.main);

          Cursor cursor = getNames();
          showNames(cursor);

        // Set up click listeners
            View addButton = findViewById(R.id.add_button);
            addButton.setOnClickListener(this);        


       }


       private Cursor getNames() {
          // Perform a managed query.
          return managedQuery(CONTENT_URI, FROM, null, null, ORDER_BY);
       }

       private void showNames(Cursor cursor) {
          // data binding
          SimpleCursorAdapter adapter = new SimpleCursorAdapter(this,
                R.layout.names, cursor, FROM, TO);
          setListAdapter(adapter);
       }


      public void onClick(View v) {
         switch (v.getId()) {
            case R.id.add_button:
                Cursor cursor = getNames();
                showNames(cursor );
                break;                      
         }
     }
}

What have i done wrong? many thanks for your help.

Answer 1

In these lines, View addButton = findViewById(R.id.add_button); addButton.setOnClickListener(this);

Specify which view you are using instead of using View. e.g :- Button addButton =(Button) findViewById(R.id.add_button); may be you've not cast on which View's onclicklistener you want the event