1: Anatomy of Basic Android Project

Created: Apr 1, 2021 12:03 PM link: https://developer.android.com/codelabs/kotlin-android-training-app-anatomy?continue=https%3A%2F%2Fdeveloper.android.com%2Fcourses%2Fpathways%2Fkotlin-fundamentals-two%23codelab-https%3A%2F%2Fdeveloper.android.com%2Fcodelabs%2Fkotlin-android-training-app-anatomy#0

Activities

• AppCompatActivity
  • AppCompatActivity is a subclass of Activity that supports all modern Android features while providing backward compatibility with older versions of Android. To make your app available to the largest number of devices and users possible, always use AppCompatActivity.

Views

• All UI elements in the app layout are subclasses of the [View](http://developer.android.com/reference/android/view/View.html) class

View attributes

• android:layout_width android:layout_height
  • The match_parent value stretches the view to its parent’s width or height. The wrap_content value shrinks the view to fit the view’s contents.

Strings

• String resources are contained in the res/values/string.xml file.
• To extract strings, use Alt+Enter (Option+Enter on a Mac). Select Extract string resources from the popup menu.

Using view

val rollButton: Button = findViewById(R.id.roll_button)
rollButton.setOnClickListener { rollDice() }

• android:id
• findViewById()
• setOnClickListener()

Question 1

Which method on an Activity inflates the app’s layout and makes its views available as objects?

• onCreate()
• setClickListener()
• setContentView()
• show()

In onCreate(), you specify which layout is associated with the activity, and you inflate the layout. The setContentView() method does both those things.

override fun onCreate(savedInstanceState: Bundle?) {   
	super.onCreate(savedInstanceState)   
	setContentView(R.layout.activity_main)
}

Question 2

Which view attribute do you use to set the width of a view so that it adjusts to fit the content?

• android:view_width="wrap"
• **android:layout_width="wrap_content"**
• android:layout_height="wrap_content"
• android:layout_width="match_parent"