How to start new activity on button click

Question

In an Android application, how do you start a new activity (GUI) when a button in another activity is clicked, and how do you pass data between these two activities?

Answer 1

Kotlin

First Activity

startActivity(Intent(this, SecondActivity::class.java)
  .putExtra("key", "value"))

Second Activity

val value = getIntent().getStringExtra("key")

Suggestion

Always put keys in constant file for more managed way.

companion object {
    val PUT_EXTRA_USER = "user"
}
startActivity(Intent(this, SecondActivity::class.java)
  .putExtra(PUT_EXTRA_USER, "value"))