iphone API's for tea time application

i want to know what API's in iPhone that we used to:

• Achieve an action by pressing a button
• Show normal inpu开发者_StackOverflow中文版t fields
• Give access to a persistent storage
• Realize a count-down timer

• Achieve an action by pressing a button
  • UIButton's -addTarget: action: forControlEvents: will help you out there.
• Show normal input fields
  • You'll be looking for UITextField here.
• Give access to a persistent storage
  • Either use the SQLite C API or Core Data
• Realize a count-down timer
  • Use NSTimer.