Look at the android.com
If the summary has a String formatting marker in it (i.e. “%s” or “%1$s”), then the current entry value will be substituted in its place when it’s retrieved.
Good solution is on stackoverflow.
Google about pickers
A flowchart for background work, alarms, and your Android app
Pro-tip by +Ian Lake
For many apps, doing work in the background can be an important part of building a great experience. Continue reading A flowchart for background work, alarms