您的问题就在这里：

//set listeners
        editText1.addTextChangedListener(textWatcher);
        editText1.addTextChangedListener(textWatcher);

您没有设置textWatcher到editText2，所以你总是检查条件，如果你写里面editText1

You are not setting the textWatcher to editText2, so you are always checking the condition if you write inside editText1