Hanafi
The sources give no view for it here.
فرقعة الأصابع وتشبيكها في الصلاة
هل تبطل صلاة من تعمّد فرقعة أصابعه أو تشبيكها فيها؟
Each school’s answer
Hanafi
Not stated in the sources
Maliki
Not stated in the sources
Shafi'i
Not stated in the sources
Hanbali
Not stated in the sources
The texts
٤٠٥ - مَسْأَلَةٌ: وَمَنْ تَعَمَّدَ فَرْقَعَةَ أَصَابِعِهِ أَوْ تَشْبِيكَهَا فِي الصَّلَاةِ بَطَلَتْ صَلَاتُهُ، لِقَوْلِهِ - صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ - «إنَّ فِي الصَّلَاةِ لَشُغْلًا» [مَسْأَلَةٌ صَلَّى مُعْتَمِدًا عَلَى عَصًا أَوْ عَلَى جِدَارٍ أَوْ عَلَى إنْسَانٍ أَوْ مُسْتَنِدًا]
From the schools’ own books
Maliki
The sources give no view for it here.
Shafi'i
The sources give no view for it here.
Hanbali
The sources give no view for it here.
What bears this mark is in our words, our standard wording; the books’ texts stay as they are.