Intent for activity navigation in Android Kotlin - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an Intent in Android development?

An Intent is a message object used to request an action from another app component, like starting a new screen (activity).

beginner

How do you start a new activity using an Intent in Kotlin?

You create an Intent with the current context and the target activity class, then call startActivity(intent).

intermediate

What is the purpose of the Context parameter when creating an Intent?

Context tells the Intent where it is starting from, usually the current activity or application environment.

intermediate

How can you pass data to the new activity using an Intent?

Use intent.putExtra(key, value) to add data, which the new activity can retrieve from its intent.

intermediate

What method do you use to retrieve data sent via Intent in the new activity?

Use intent.getStringExtra(key) or similar methods inside the new activity to get the passed data.

Which class is used to start a new activity in Android?

A Intent

B ActivityManager

C View

D Service

Intent is the class used to request starting a new activity.

What method starts the new activity after creating an Intent?

A launchActivity()

B startActivity()

C beginActivity()

D openActivity()

startActivity() is called with the Intent to open the new activity.

How do you pass a string value "username" to the next activity?

A intent.addData("username", value)

B intent.setData("username", value)

C intent.sendData("username", value)

D intent.putExtra("username", value)

putExtra() adds extra data to the Intent.

Which parameter is required first when creating an Intent to navigate?

A Current context

B Bundle object

C Intent action string

D Target activity class

The current context is the first parameter to tell where the Intent starts.

How do you retrieve a string extra named "username" in the new activity?

A intent.getData("username")

B intent.getExtraString("username")

C intent.getStringExtra("username")

D intent.retrieveExtra("username")

getStringExtra() retrieves string data passed via Intent.

Explain how to navigate from one activity to another using Intent in Android Kotlin.

Think about how you tell the app to open a new screen and share information.

Describe the role of Context and Intent in activity navigation.

Imagine Context as your current location and Intent as the invitation to go somewhere else.

Practice

1. What is the main purpose of an Intent in Android Kotlin?

easy

A. To store user data permanently

B. To style the user interface

C. To navigate from one activity to another

D. To handle background tasks

Solution

1. Step 1: Understand Intent usage

   An Intent is used to request an action from another app component, commonly to start a new activity.

2. Step 2: Identify navigation role

   In Android, Intent is primarily used to navigate between screens (activities).

3. Final Answer:

   To navigate from one activity to another -> Option C

4. Quick Check:

   Intent = Navigation [OK]

Hint: Intent is for moving between screens [OK]

Common Mistakes:

• Confusing Intent with data storage
• Thinking Intent styles UI
• Assuming Intent handles background tasks

2. Which of the following is the correct syntax to create an Intent to start SecondActivity from the current activity?

easy

A. val intent = Intent(this, SecondActivity::class.java)

B. val intent = Intent(SecondActivity, this::class.java)

C. val intent = Intent(this, SecondActivity)

D. val intent = Intent(SecondActivity::class.java, this)

Solution

1. Step 1: Check Intent constructor parameters

   The Intent constructor requires the current context and the target activity class with ::class.java.

2. Step 2: Validate syntax correctness

   val intent = Intent(this, SecondActivity::class.java) correctly uses this for context and SecondActivity::class.java for the target.

3. Final Answer:

   val intent = Intent(this, SecondActivity::class.java) -> Option A

4. Quick Check:

   Intent(this, TargetActivity::class.java) = Correct [OK]

Hint: Use this and TargetActivity::class.java in Intent [OK]

Common Mistakes:

• Swapping parameters order
• Omitting ::class.java
• Using activity instance instead of class

3. What will happen when the following code runs inside an activity?

val intent = Intent(this, DetailActivity::class.java)
startActivity(intent)

medium

A. The app will crash due to missing permissions

B. The current activity will close and DetailActivity will open

C. Nothing will happen because startActivity is missing parameters

D. DetailActivity will open on top of the current activity

Solution

1. Step 1: Analyze Intent creation

   The Intent is correctly created to open DetailActivity from the current context.

2. Step 2: Understand startActivity behavior

   Calling startActivity launches the new activity on top without closing the current one.

3. Final Answer:

   DetailActivity will open on top of the current activity -> Option D

4. Quick Check:

   startActivity(intent) = Opens new screen on top [OK]

Hint: startActivity opens new screen on top [OK]

Common Mistakes:

• Thinking startActivity closes current activity
• Assuming permissions needed for navigation
• Believing startActivity requires extra parameters

4. Identify the error in this code snippet that tries to start ProfileActivity:

val intent = Intent(ProfileActivity::class.java, this)
startActivity(intent)

medium

A. The parameters in Intent are reversed

B. startActivity is missing parentheses

C. ProfileActivity should be an instance, not a class

D. Intent requires a string action, not classes

Solution

1. Step 1: Check Intent constructor parameter order

   The Intent constructor expects the current context first, then the target activity class.

2. Step 2: Identify parameter reversal

   Here, the target activity class is given first, then the context, which is incorrect.

3. Final Answer:

   The parameters in Intent are reversed -> Option A

4. Quick Check:

   Intent(this, TargetActivity::class.java) = Correct order [OK]

Hint: Context first, target class second in Intent [OK]

Common Mistakes:

• Swapping context and target activity
• Forgetting ::class.java
• Using activity instance instead of context

5. You want to open SettingsActivity and close the current activity so the user cannot return by pressing back. Which code snippet achieves this?

hard

A. val intent = Intent(this, SettingsActivity::class.java)
startActivity(intent)

B. val intent = Intent(this, SettingsActivity::class.java)
startActivity(intent)
finish()

C. val intent = Intent(this, SettingsActivity::class.java)
finish()
startActivity(intent)

D. val intent = Intent(this, SettingsActivity::class.java)
startActivityForResult(intent, 1)

Solution

1. Step 1: Understand startActivity and finish

   startActivity opens the new activity; finish closes the current one.

2. Step 2: Order matters

   Calling finish() after startActivity ensures the new screen opens before current closes.

3. Step 3: Check options

   val intent = Intent(this, SettingsActivity::class.java) startActivity(intent) finish() correctly calls startActivity then finish to prevent back navigation.

4. Final Answer:

   val intent = Intent(this, SettingsActivity::class.java) startActivity(intent) finish() -> Option B

5. Quick Check:

   startActivity + finish = Open new and close current [OK]

Hint: Call finish() after startActivity to close current [OK]

Common Mistakes:

• Calling finish() before startActivity
• Not calling finish() at all
• Using startActivityForResult unnecessarily