androidfred

Lambdas, Functions, Functors and Monads

Intro

If you've been exposed to lambdas (whether in Java or Kotlin), you already know at least the basics of what lambdas are, the syntax for using them, that they're more succinct than instantiating anonymous classes etc etc.

Rather than talking about that, I figured we would talk about functions and lambdas on a higher level.

I think most of us are familiar with map and, having used it quite a bit, have an intuitive understanding of what any given call to map will do.

Does anyone know a bit more about map, what it is and where it came from?

passiondroid

Android uses hexadecimal ARGB values, which are formatted as #AARRGGBB. That first pair of letters, the AA, represent the alpha channel. You must convert your decimal opacity values to a hexadecimal value. Here are the steps:

Alpha Hex Value Process

• Take your opacity as a decimal value and multiply it by 255. So, if you have a block that is 50% opaque the decimal value would be .5. For example: .5 x 255 = 127.5

• The fraction won't convert to hexadecimal, so you must round your number up or down to the nearest whole number. For example: 127.5 rounds up to 128; 55.25 rounds down to 55.

• Enter your decimal value in a decimal-to-hexadecimal converter, like http://www.binaryhexconverter.com/decimal-to-hex-converter, and convert your values.