Xtykutl

The Code A is good, I hope to optimize it, so I write the Code B.

I'm not sure whether the Code B is always correct.

It will be OK if Kotlin check clipboard.hasPrimaryClip() first, then check clipboard.primaryClipDescription.hasMimeType(MIMETYPE_TEXT_PLAIN) next.

It maybe crash if Kotlin check clipboard.primaryClipDescription.hasMimeType(MIMETYPE_TEXT_PLAIN) first, the check clipboard.hasPrimaryClip() next, right?

Code A

clipboard.addPrimaryClipChangedListener {

   if (clipboard.hasPrimaryClip() ) {

          if (clipboard.primaryClipDescription.hasMimeType(MIMETYPE_TEXT_PLAIN)) {



         }

   }

}

Code B

clipboard.addPrimaryClipChangedListener {

  if (clipboard.hasPrimaryClip() && clipboard.primaryClipDescription.hasMimeType(MIMETYPE_TEXT_PLAIN) ) {



  }

}

As mentioned in the comments, the principle behind this is described as "short circuiting":

Short-circuit evaluation [...] is the semantics of some Boolean operators in some programming languages in which the second argument is executed or evaluated only if the first argument does not suffice to determine the value of the expression.

That means clipboard.hasPrimaryClip() will always be evaluated. If it's false
, the condition fails without looking any further. If it is true though, clipboard.primaryClipDescription.hasMimeType(MIMETYPE_TEXT_PLAIN) will be evaluated as well.

if conditions run sequentially. That means it will first check the left condition and if the operator is AND and left condition return false then it won't check the right condition. So yes, you can merge two conditions.