AlertDialog.java

final AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
builder
        .setTitle("El título")
        .setNegativeButton("Cancelar", null)
        .setPositiveButton("OK", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                Toast.makeText(MainActivity.this, "Click en ok", Toast.LENGTH_LONG).show();
            }
        });
final AlertDialog alertDialogPersonalizado = builder.create();