with和run是否有相同的功能，只是语法不同，或者with和run之间有什么主要区别？
哪一种是正确的方法？
adapter.run {
notifyDataSetChanged()
if (activityDetails.isEmpty())
emptyText.visibility = View.VISIBLE
else
emptyText.visibility = View.GONE
}
with(adapter){
notifyDataSetChanged()
if (activityDetails.isEmpty())
emptyText.visibility = View.VISIBLE
else
emptyText.visibility = View.GONE
}
They have only syntactic difference, run is an extension function while with is not. Here are the definitions (in kotlin-sdlib:1.0.3):
public inline fun <T, R> T.run(block: T.() -> R): R = block() // equivalent to this.block()
public inline fun <T, R> with(receiver: T, block: T.() -> R): R = receiver.block()
由于run是一个扩展函数，它又有一个T类型的隐式参数，因此参数类型是相同的.这些职能机构实际上也是相同的.
Their performance should also be equivalent since both are inline functions: the resulting bytecode should only contain the inlined block body.
函数用法的差异都是由run是一个扩展这一事实造成的.
First, run is suitable for calls chaining:
foo.run { bar }.run { baz }
其次，也是更重要的是，如果声明的变量类型具有具有相同签名的run个函数，则将调用该函数，而不是调用扩展.并且run可以被另一个扩展所遮蔽.这是how extensions are resolved美元.示例:
class MyClass {
fun <R> run(blockIgnored: MyClass.() -> R): Nothing = throw RuntimeException()
}
"abcdefg".run { println("x") } // prints "x"
MyClass().run { println("x") } // throws RuntimeException
(MyClass() as Any).run { println("x") } // prints "x"