NoClassDefFoundError: Landroid/support/v7/appcompat/R$styleable的失败解决方案。

Newbie trying to finish the My first App tutorial provided by Google. On the way to this fatal exception I did import a lot of random packages to get rid of "cannot be resolved" errors for a number of things, ActionBarActivity, EditText, Fragment, LayoutInflater, etc, but not sure this matters. Anyway, my app crashes and produces a Fatal exception when I click on the "Send" button in the Main Activity. Here is my code and logcat file.Newbie trying to finish the My first App tutori