Question

I want to write an app sending messages.
How can I tell Android OS that when a user ask to send a message (sms) give him my app as an alternative?
I know viber and whatsapp do things like that. I didn’t find the documentation. Probably I am missing something.

Answer 1

Have you added the SMS send to intent filter to your manifest?

 <intent-filter>
    <category android:name="android.intent.category.DEFAULT"/>
    <action android:name="android.intent.action.SENDTO"/>
    <data android:scheme="smsto"/>
    <data android:scheme="sms"/>
 </intent-filter>