But intents can be much more than just social network sharing or Google Play URL opening!
I've been an Android user for a long time already. Still, sometimes the OS and some apps surprise me and impress me about the capabilities of the OS. I want to share few of them here hopefully to inspire more developers to think how they could integrate their apps more tightly to others.
Let's say that I have agreed to meet with my friend in a coffee shop and I have typed in the meeting into my Google Calendar. (Side note: I love how easy to use the Google Calendar is as the cloud service keeps everything up-to-date on all of my devices.)
I can tap the address to see selection of apps that can give me more info about the address. I know where the coffee shop is but what I want to know is when do I have to leave home to be there on time. I open Öffi - Public Transport Buddy, an app that know everything about public transportation timetables at least in some parts of Europe. The app does not open from an empty screen but instead has both fields, start point and end point, prefilled. The app know where I am and it knows that I very likely opened the address with this app because I want to get there. Literally all I need to do to see all public transportation connections is to tap "Go".
It is noteworthy that neither of these apps (the Google Calendar or Öffi) need to have any specific functionality implemented in them. The Android platform takes care of everything.
Second example of an app that impressed me lately is Evernote. Let's say that I arrived to the meeting with my friend and I want to make a note. I open Evernote and tap "New note". Evernote realises that I have a calendar event that is currently ongoing. It prefills the note header with the calendar event title and location. Brilliant!
Gigbeat is one of my favourite apps. Not only have they done brilliant work with their design (especially in the upcoming new version) but the app is aware of what else is going on in the device.
The app knows where I am and it pays attention to what I'm playing on my music player (Google Music in my case). If I happen to play a song of an artist that is coming to near me the app notifies me. Again, brilliant!
Users still hate writing on their mobile devices. The above examples all demonstrate that utilising the system tools correctly you can help your users to achieve their goals in the best case without any writing. Integrating to other apps via the amazing intent system can make your app stand up in the crowd of app!