i found a way to send plain text email using intent:
final Intent emailIntent = new Intent(android.content.Intent.ACTION_SEND);
emailIntent.setType("text/plain");
emailIntent.putExtra(android.content.Intent.EXTRA_EMAIL, new
String[]{"example@mail.com"});
emailIntent.putExtra(android.content.Intent.EXTRA_SUBJECT, "Subject");
emailIntent.putExtra(android.content.Intent.EXTRA_TEXT, "Test");
But I need to send HTML formatted text.
Trying to setType("text/html") doesn't work.
Been trying to send html via gmail app for a while, so decided to leave some insight on what I found, just in case someone else is having similar issues.
Seems like no matter what I did, I couldn't get the html to have bold text in it. Then I've tried switching to outlook client and to my surprise it was working just fine. Html markup was also working on other older devices, but not on mine (galaxy s7 API 26), so I figured, that gmail app seems to have dropped support for html syntax that comes from intent or maybe now you're required to provide it in some very specific way which is not clearly documented.
Last gmail version that worked for me was version 6.9.25... on Nexus 5X API 25 emulator (Nougat) And it stopped working starting version 7.5.21... On Nexus 5x API 26 emulator (Oreo)
I haven't (yet) started Android development, but the documentation for the intent says that if you use EXTRA_TEXT, the MIME type should be text/plain. Seems like if you want to see HTML, you'd have to use EXTRA_STREAM instead...
What about just trying to add some html in the text area?
emailIntent.putExtra(android.content.Intent.EXTRA_TEXT, "<strong>Test</strong>");