Gerar de 1 a 26 verifica repetidos avisa quantos e coloca cor vermelha

List<Set<Integer>> uniqueNumbersList = new ArrayList<>();
List<List<Integer>> randomNumbersList = new ArrayList<>();
List<TextView> textViewList = new ArrayList<>();

for (int i = 0; i < 4; i++) {
    Set<Integer> uniqueNumbers = new HashSet<>();
    while (uniqueNumbers.size() < 25) {
        uniqueNumbers.add((int)(Math.random()*26) + 1);
    }
    uniqueNumbersList.add(uniqueNumbers);
    List<Integer> randomNumbers = new ArrayList<>(uniqueNumbers);
    randomNumbersList.add(randomNumbers);
    TextView textView = (TextView) findViewById(getResources().getIdentifier("textview" + (i + 1), "id", getPackageName()));
    textView.setText(TextUtils.join(", ", randomNumbers));
    textViewList.add(textView);
}

Set<Integer> repeatedNumbers = new HashSet<>(randomNumbersList.get(0));
for (int i = 1; i < 4; i++) {
    repeatedNumbers.retainAll(randomNumbersList.get(i));
}

for (Integer num : repeatedNumbers) {
    for (int i = 0; i < 4; i++) {
        int start = textViewList.get(i).getText().toString().indexOf(num.toString());
        int end = start + num.toString().length();
        Spannable spannable = new SpannableString(textViewList.get(i).getText());
        spannable.setSpan(new ForegroundColorSpan(Color.RED), start, end, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
        textViewList.get(i).setText(spannable);
    }
}

TextView textView5 = (TextView) findViewById(R.id.textview5);
String repeatedNumber = "Números repetidos: " + repeatedNumbers.size();
textView5.setText(repeatedNumber);