尝试在空对象引用上调用虚拟方法'void android.widget.EditText.addTextChangedListener（android.text.TextWatcher）'

Question

我在运行应用程序时尝试在添加电子邮件地址后在电子邮件edittext上添加（addTextChangedListener）

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.EditText.addTextChangedListener(android.text.TextWatcher)' on a null object reference
        at com.anandjha770.a_kart.SignUpFragment.onViewCreated(SignUpFragment.java:90)
        at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManager.java:1471)
        at androidx.fragment.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1784)
        at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManager.java:1852)
        at androidx.fragment.app.BackStackRecord.executeOps(BackStackRecord.java:802)
        at androidx.fragment.app.FragmentManagerImpl.executeOps(FragmentManager.java:2625)
        at androidx.fragment.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2411)
        at androidx.fragment.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManager.java:2366)
        at androidx.fragment.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2273)
        at androidx.fragment.app.FragmentManagerImpl$1.run(FragmentManager.java:733)
        at android.os.Handler.handleCallback(Handler.java:873)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:193)

我的代码如下：-

   email.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {

        }

        @Override
        public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
            checkInputs();
        }

        @Override
        public void afterTextChanged(Editable editable) {

        }
    });