Change Custom Toolbar Text

You forgot to set this:

 setSupportActionBar(toolbar);

and this:

getSupportActionBar().setDisplayShowTitleEnabled(false); 

YOUR ACTIVITY LIKE THIS:

Toolbar toolbar = (Toolbar) findViewById(R.id.toolbarCustom);

setSupportActionBar(toolbar);

TextView textView = (TextView)toolbar.findViewById(R.id.toolbarTextView);
textView.setText("String");

getSupportActionBar().setDisplayShowTitleEnabled(false);

It will be like that. Java Code:

Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); //here toolbar is your id in xml
setSupportActionBar(toolbar);
getSupportActionBar().setTitle("String"); //string is custom name you want