Executar um Toast dentro de uma Thread

Button btn = (Button) findViewById(R.id.btnAdd);

btn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
new Thread(new Runnable() {
@Override
public void run() {
runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(MinhaClasse.this, "Tracking number is invalid", Toast.LENGTH_LONG).show();
}
});
}
}).start();
}
});