Will Donald Trump still be a candidate for president by mid-July?

[Stranger in a strange land]

Yes. Like it or not, he won the most delegates fair and square (actually more than fair and square, because he won in spite of the delegate games of the Establishment and the Cruz Campaign). Suspending the rules and staging a convention coup would not only be highly undemocratic, and much of the public wouldn't understand how it was legal, and would probably result in literal blood in the streets.