I found a solution:
<TextView
android:id="@+id/textView5"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:clickable="true"/>
TextView mailTV = (TextView) findViewById(R.id.textView5);
mailTV.setText(Html.fromHtml("<a href=\"mailto:"+getString(R.string.email)+"?subject="+getString(R.string.email_subject)+"\" >"+getString(R.string.email)+"</a>"));
mailTV.setMovementMethod(LinkMovementMethod.getInstance());