How to pass data from one activity to another in…

Data can be passed using Intent:

In the source Activity: Put data into the Intent's Extras using methods like putExtra(String key, value).

// Preparing the Intent
val intent = Intent(this, TargetActivity::class.java)
// Adding data
intent.putExtra("myString", "Hello from the first Activity")
intent.putExtra("myInt", 123)
intent.putExtra("myBool", true)
// You can also pass objects that implement Parcelable or Serializable
// intent.putExtra("myObject", myParcelableObject)

// Starting the new Activity
startActivity(intent)

In the target Activity: Retrieve data from the Extras of the Intent received in onCreate or onNewIntent.

// In onCreate() of the target Activity
override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_target)

    // Get the Intent that started this Activity
    val intent = intent

    // Extract data by key
    val myString = intent.getStringExtra("myString")
    val myInt = intent.getIntExtra("myInt", 0) // Second argument is default value
    val myBool = intent.getBooleanExtra("myBool", false)

    // Handle the extracted data
    println("Received string: $myString")
    println("Received number: $myInt")
    println("Received boolean: $myBool")

    // For Parcelable or Serializable objects
    // val myObject = intent.getParcelableExtra<MyParcelableClass>("myObject")
}

Other methods suitable for more complex scenarios or large data volumes include:

ViewModel Shared between Fragments/Activities (via SharedViewModel): Convenient for shared data between related components.
Bundle (inside Intent Extras): putExtra actually uses a Bundle internally.
Static variables/Singletons: Use cautiously, as they can lead to memory leaks and state issues.
Database/SharedPreferences: For persistent storage or data transfer requiring saving.
Event Bus (e.g., EventBus, RxJava): For passing events or data between components asynchronously.
File I/O: Saving to and reading from a file.

How to pass data from one activity to another in Android?