大部分文章介紹的禁用返回鍵方法都只適用於Activity：

public boolean onKeyDown(int keyCode, KeyEvent event) {
            if (keyCode == KeyEvent.KEYCODE_BACK) {
                return true;
            }
            return false;
        }

然後Fragment的資料比較少而且看起來都有夠麻煩XD
但是今天爬到這個文！有夠快速有夠簡單！（喜極而泣）
需要注意的是這不是onCreateView！！
直接放在class就可以啦

@Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        getView().setFocusableInTouchMode(true);
        getView().requestFocus();
        getView().setOnKeyListener(new View.OnKeyListener() {
            @Override
            public boolean onKey(View v, int keyCode, KeyEvent event) {
                if (event.getAction() == KeyEvent.ACTION_DOWN) {
                    if (keyCode == KeyEvent.KEYCODE_BACK) {
                        //go to previous fragemnt
                        //perform your fragment transaction here
                        //pass data as arguments
                        return true;
                    }
                }
                return false;
            }
        });
    }

來源：https://stackoverflow.com/questions/41647583/android-back-button-onkeylistener-inside-fragment-is-not-working