Android sharing selected text to other apps
Honestly I believe you have answered this question yourself: The app works just fine.

From what I can see, you are using the intent exactly as you are supposed to. You are also using EditText properly. But, because you have come all the way here I guess you want to hear some suggestions/criticism as well so I have tried really hard to come up with something:


You're inconsistent in adding spaces to your code. The best practice is to use VariableType variable = something; but in three lines you are writing VariableType variable=something; which makes the code a little bit harder to read.
I don't think you need to temporarily store the selectionStart and selectionEnd variables. (If you think it looks cleaner to store them in temporary variables, then by all means continue to do so) This code would be enough:

String selectedText = et.getText().toString().substring(et.getSelectionStart(), et.getSelectionEnd());


Or if you think that line is too long, 

String text = et.getText().toString();
String selectedText = text.substring(et.getSelectionStart(), et.getSelectionEnd());

Consider what would happen if there is nothing at all stored in the EditText, do you still want to start an intent even if the string is empty?