I kind of think that answer of this question would be
No by going through <a href="https://github.com/angular/protractor/issues/1798#issuecomment-74405588" rel="nofollow">Protractor issue 1798</a> and <a href="http://www.webdriverjs.com/protractor-vs-webdriverio-vs-nightwatch/" rel="nofollow">Protractor vs Webdriver-IO</a> comparisions.
Currently I have both <a href="http://www.protractortest.org/" rel="nofollow">Protractor</a> and <a href="http://appium.io/" rel="nofollow">Appium</a> configured in same project to run those
End-to-End test cases, and they work.
<strong>Problems are</strong> that,<ol><li>I have to write separate test cases for each of them. </li> <li>Cases should also work on mobile devices(Android and iOS) and protractor doesn't support native apps tests.</li> </ol>
Situation is, I am more comfortable with Protractor's settings in my current project than <a href="http://webdriver.io" rel="nofollow noreferrer">Webdriver-IO</a> which Appium uses (just a personal preference).
<strong>Question-</strong><ol><li>Is there a way of using only Protractor while writing test cases which would work using Appium and work perfectly on Devices/Emulators?</li> </ol>
I am also open for any suggestion(s).
If answer remains
No, I will change my codes to only use WebdriverIO in order to keep my test cases reusable and only once.
The answer is still
NO protractor currently does not have support for mobile native apps but you can use it for automating browsers in your mobile.
Better use <a href="http://webdriver.io/" rel="nofollow">WebdriverIO</a> but it also has its own limitations, please do check its changelog and github issues before deciding it as your webdriver framework.