I am updating Vault 3 for Android to initiate a search when the user types Enter in the search text box. Here's how I did this:

1. I created a Key Listener on the search EditText field.
2. When Enter is typed, the perfomClick is called on the search button, but only if the search button is visible and enabled.

Here's the code:

searchText = (EditText) findViewById(R.id.SearchText);
		
...

// Initiate a search when user types ENTER.
searchText.setOnKeyListener(new OnKeyListener() {
    public boolean onKey(View v, int keyCode, KeyEvent event) {
	    	boolean result = false;
		    	
	// If the event is a key-down event on the "enter" button
        if (event.getAction() == KeyEvent.ACTION_DOWN && keyCode == KeyEvent.KEYCODE_ENTER && searchButton.isEnabled() && searchButton.getVisibility() == View.VISIBLE) {
        	searchButton.performClick();
        	result = true;
        }
		        
        return result;
    }
});