its easy to find lots of music apps in the iOS app store, but they do not interconnect!
so if you choose your phone or tablet to be a looper, here are the options we found:

• Loopy
  probably the furthest developed: great graphics, multiple loops with different lenght, MIDI in for pedal control…
• EveryDay Looper
  one of the first to come out. 6 tracks of the same lenght. just remember that when you are lost, use a swipe from track 1 to 3 to get back to the menu 🙂
• RiffBox (free)
  a special app since it detects the loop lenght automatically like its hardware brother. less easy to handle, also because its not adapted to iPad size.
• VoiceJam (free)
  sophisticated but not quite intuitive interface. interesting for the effects which do not come free
• Loopr
  basic 4 track looper with MIDI sync out and MIDI pedal in. iPhone size interface (can be x2 in iPad)
• (the app called Loop creates sound very differently, have a try!)

a major limitation of all those apps are that there is no way to digitally integrate them with other software tools. so they either serve as:

• just loopers to have fun with, anywhere
• connect the output with a mini audio connector to some other analog tool
• connect effect units before the looper using an adapter 

so far the apps that allow to mix several effect modules like AmpliTube or Tabletop do not include a looper

Android as an audio latency problem which depends on drivers that are not made by the Android programmers as explained here and here