Android App Activity Lifecycle

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Questions and Answers

Which callback method is invoked only once during the entire lifecycle of an activity?

`onStart()`
`onResume()`
`onCreate()` (correct)
`onPause()`

An activity transitions from the visible state to a state where it is no longer visible. Which callback method is invoked during this transition?

`onStart()`
`onPause()` (correct)
`onRestart()`
`onResume()`

Under what circumstance is the `onDestroy()` callback method invoked?

When the activity is resumed after being stopped.
When the activity is finishing or being destroyed due to configuration change. (correct)
When the activity becomes hidden.
When the activity is initially created.

An activity is currently stopped. Which callback method is invoked if the activity returns to interact with the user?

<code>onRestart()</code> (B) Signup and view all the answers

What role does the back stack play when a new activity starts?

It stops the previous activity but preserves it in a stack. (A) Signup and view all the answers

Which of the following accurately describes the purpose of an Intent in Android development?

It's a message used to request an action from another activity or app component. (C) Signup and view all the answers

An Intent needs to pass data to the receiving activity. Which part of the Intent is responsible for carrying this data?

Intent data/object (C) Signup and view all the answers

How might an Intent, through the use of flags, influence the Android system when launching an activity?

By instructing the system on how to treat an activity post-launch. (C) Signup and view all the answers

What differentiates an explicit Intent from an implicit Intent?

Explicit Intent specifies the exact component to handle the Intent, while implicit Intent declares a general action. (B) Signup and view all the answers

If you want to specify the exact component to handle the Intent, which type of Intent would you use?

Explicit Intent (D) Signup and view all the answers

How do you programmatically set up navigation between two activities using explicit Intents?

By creating an Intent that specifies the target activity and starting it using <code>startActivity()</code>. (B) Signup and view all the answers

What is the significance of the `parentActivityName` attribute in the `<activity>` element of the `AndroidManifest.xml` file?

It indicates the activity that is the logical parent of the current activity, enabling navigation via a left-facing arrow. (B) Signup and view all the answers

In the context of Android activities, what does the term "activity lifecycle" refer to?

The different stages an activity goes through, from creation to destruction. (C) Signup and view all the answers

Consider an activity that is currently visible and running in the foreground. If a phone call interrupts the user, which callback method is MOST likely to be invoked first?

<code>onPause()</code> (B) Signup and view all the answers

What is the primary purpose of calling `super.onCreate(savedInstanceState)` within the `onCreate()` method of an Activity?

To ensure that the parent class's <code>onCreate()</code> method is executed, which is important for proper setup and state restoration. (B) Signup and view all the answers

In the code snippet `android:onClick="launchNextActivity"`, what does `launchNextActivity` refer to?

A method defined within the activity that handles the button click. (C) Signup and view all the answers

If a user rotates their device, what is the typical behavior of an Android activity, and which lifecycle methods are involved?

The activity is destroyed and recreated, involving <code>onDestroy()</code> and <code>onCreate()</code>. (C) Signup and view all the answers

To display a user interface for an activity, which method is commonly used and what parameter does it take?

<code>setContentView()</code>, taking a layout resource ID as a parameter. (B) Signup and view all the answers

Which combination of steps is required to properly implement a new Activity in an Android application?

Create a Java class that extends Activity, declare the Activity in AndroidManifest.xml, and implement a basic UI in an associated XML layout file. (C) Signup and view all the answers

What purpose does `Toast.makeText(getApplicationContext(), "New activity launched!", Toast.LENGTH_SHORT).show();` serve in verifying Intent functionality?

It displays a short message on the screen to confirm the action's success. (D) Signup and view all the answers

Flashcards

Activity (in Android)

Represents a single screen in an app for a focused task, usually full-screen.

onCreate()

Called when the app is launched; happens only once per the activity's life.