Does teachers have the right to check text messages on students’ mobile phones?

It is an infringement. Rights subjects have the right to keep the contents of personal letters, telegrams, phone calls, faxes and discussions confidential, and prohibit others from illegally eavesdropping or stealing other people's letters, peeking into other people's diaries, spying on the contents of other people's private documents, and making them public. But you have to consider your own situation and try to reconcile.