How to update array adapter dynamically and update listview with new adapter?

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Mobile

Android

ListView

I am using a database to store chemical formulas in.

I have an activity where I use a listview to display the formulas and when I add a formula I want it to display on the listview.

I tried using notifyDataSetChanged() but I'm not so sure this will redraw the listview. Also, whenever I click the menu item to add another formula, the previous formula which I have added is added to the listview.

Here is my activity:

<pre>public class FormulaActivity extends WindowListActivity {
	private ArrayAdapter<String> aa;
	private List<String> names = new ArrayList<String>();
	
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		tvHeader.setText("Formula Saves");
		
		setContentView(R.layout.formula);
		
		aa = getArrayAdapter();
		setListAdapter(aa);
	}
	
	@Override
	public void onListItemClick(ListView l, View v, int position, long id) {
		// Display dialog of formula
	}
	
	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		super.onCreateOptionsMenu(menu);
		getMenuInflater().inflate(R.menu.formula_menu, menu);
		return true;
	}
	
	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
		super.onOptionsItemSelected(item);
		
		switch(item.getItemId()) {
		case R.id.itmAddFormula:
			List<String> temp = names;
			names.clear();
			addFormula();
			
			int lastIndex = formulaDataSource.getAllFormulas().size() - 1;
			temp.add(formulaDataSource.getAllFormulas().get(lastIndex).getName());
			names.addAll(temp);
			aa.notifyDataSetChanged();
			
			break;
			
		default:
			break;
		}
		
		return true;
	}
	
	public ArrayAdapter<String> getArrayAdapter() {
		for(int i = 0; i < formulaDataSource.getAllFormulas().size(); i++) {
			names.add(formulaDataSource.getAllFormulas().get(i).getName());
		}
		
		return new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, 
				names);
	}
}

Here is addFormula() if necessary:

protected void addFormula() {
		AlertDialog.Builder builder = new AlertDialog.Builder(WindowListActivity.this);
		builder.setTitle("Add Formula");
		
		LayoutInflater inflater = getLayoutInflater();
		View layout  = inflater.inflate(R.layout.add_formula_dialog, (ViewGroup) findViewById(R.id.llAddFormula));
	
		final EditText etFormulaName = (EditText) layout.findViewById(R.id.etFormulaName);
		final EditText etFormula = (EditText) layout.findViewById(R.id.etFormula);
		final EditText etFormulaDesc = (EditText) layout.findViewById(R.id.etFormulaDesc);
		
		builder.setPositiveButton("Add", new DialogInterface.OnClickListener() {
			public void onClick(DialogInterface dialog, int which) {
				// Add the formula to database
				formulaDataSource.createFormula(etFormulaName.getText().toString(),
						etFormula.getText().toString(),
						etFormulaDesc.getText().toString());
				
			}
		});
		
		builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
			public void onClick(DialogInterface dialog, int which) {
				dialog.cancel();
			}
		});
		
		builder.setView(layout);
		builder.create().show();
	}