title: How to set action, category and data for intent?
body: <p>I'm programming an Android application. I want to invoke other applications to perform certain operations(Sending emails etc.) How do I know which action and category to set for the intent? Should I look other application's intent filter? What if that application is not open source? </p>
  
  <p>Also, for the data or extra attribute, I don't know how the 3rd party application will handle my intent, so I do not know how to set the attributes. For example, I want one string as the title of the email, one string as the content of the email, and another string as the recipient, and a picture as the attachment. Can I include all these information in the intent? What if the 3rd party application don't provide any functionality to handle it?</p>