Android Intents

Introduction

Intents

There are two types of intents

• Explicit
• Implicit

Explicit

We can start an explicit intent with

val intent = Intent(this.MyActivityClass::class.java_
startActivity(intent)

Implicit

No destination intent is defined. The user will be prompted for which application to use. Not the use of the apply operator.

val intent = Intent().apply {
    action = Intent.ACTION_SEND
    putExtra(Intent.EXTRA_TEXT,"Hello World")
    type = "text/plain"
}
startActivity(intent)

Quite nice compared with the code without the apply.

val intent = Intent()
intent.action = Intent.ACTION_SEND
intent.putExtra(Intent.EXTRA_TEXT,"Hello World")
intent.type = "text/plain"
startActivity(intent)

Implicit With Choice

Android looks at the action, and prompts the user for all app which handle this.The user can make their choice a default however we can override this and force a choice. Notice we should always check for a valid intent or the app will crash

val chooser = Intent.createChooser)myIntent, title)
if(intent.resolveActivity(packageManager) !=null) {
  startActivity(chooser)
} else {
  Log.d(...)
}