It is my first application on IOS, just for replacing the origin keyboard when I want to code using iphone.

• Key functions
  • Basic key functions
  • Slide a button to input a symbol
  • Arrow key function
  • Long pressing deletion
  • Uppercase char input once (click shift)
  • Text-transform control (long press shift)
  • Config key
  • Number key?
• Application icon
• Key icons
• Characters layout
• Keyboard size
• Main storyboard layout
• Configs
  • Indent by tap or spaces
• Press feedback
  • voice
  • enlarge key upside when press (like apple keyboard)
• Programming language words dict
• Redraw buttons when rotato the device

The Swift Programming Language - Official Document

App Extension - Custom Keyboard

TXInputMethod - txHe

The icon resize script is referred to IconSplashMaker

Thanks for google & stackoverflow