Navigator.push and pop in Flutter - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to navigate to SecondPage when the button is pressed.

Flutter

ElevatedButton(
  onPressed: () {
    Navigator.[1](context, MaterialPageRoute(builder: (context) => SecondPage()));
  },
  child: Text('Go to Second Page'),
)

Drag options to blanks, or click blank then click option'

ApopUntil

Bpush

CpushReplacement

Dpop

Attempts:

3 left

💡 Hint

Common Mistakes

Using pop instead of push will try to go back, not forward.

Using pushReplacement removes the current page, which is not needed here.

Navigator.push adds a new page on top of the current one, allowing navigation forward.

2fill in blank

medium

Complete the code to go back to the previous page when the button is pressed.

Flutter

ElevatedButton(
  onPressed: () {
    Navigator.[1](context);
  },
  child: Text('Go Back'),
)

Drag options to blanks, or click blank then click option'

Apop

Bpush

CpushReplacement

DpopUntil

Attempts:

3 left

💡 Hint

Common Mistakes

Using push will add a new page instead of going back.

Using popUntil requires a condition and is more complex.

Navigator.pop removes the current page and returns to the previous one.

3fill in blank

hard

Fix the error in the code to navigate to ThirdPage correctly.

Flutter

Navigator.push(context, [1](builder: (context) => ThirdPage()));

Drag options to blanks, or click blank then click option'

AMaterialPageRoute

BCupertinoPageRoute

CRoute

DPageRouteBuilder

Attempts:

3 left

💡 Hint

Common Mistakes

Using Route directly causes an error because it is abstract.

Using CupertinoPageRoute changes the style to iOS, which may not be intended.

MaterialPageRoute is the standard route for material design pages in Flutter.

4fill in blank

hard

Fill both blanks to navigate to FourthPage and then remove the current page from the stack.

Flutter

Navigator.[1](context, MaterialPageRoute(builder: (context) => FourthPage()));
// This removes the previous page
Navigator.[2](context);

Drag options to blanks, or click blank then click option'

ApushReplacement

Bpop

Cpush

DpopUntil

Attempts:

3 left

💡 Hint

Common Mistakes

Using push instead of pushReplacement keeps the old page in the stack.

Using popUntil requires a condition and is more complex.

pushReplacement adds a new page and removes the current one. pop removes the top page from the stack.

5fill in blank

hard

Fill all three blanks to navigate to FifthPage, pass data, and then pop back with a result.

Flutter

final result = await Navigator.[1](context, MaterialPageRoute(builder: (context) => FifthPage(data: [2])));
Navigator.[3](context, result);

Drag options to blanks, or click blank then click option'

Apush

B'Hello from FirstPage'

Cpop

DpushReplacement

Attempts:

3 left

💡 Hint

Common Mistakes

Using pushReplacement does not allow awaiting a result.

Not passing data correctly causes errors.

Using push instead of pop to return causes errors.

push navigates to a new page and waits for a result. Data is passed as an argument. pop returns to the previous page with the result.

Practice

1. What does Navigator.push do in a Flutter app?

easy

A. It clears all screens and shows a blank page.

B. It closes the current screen and returns to the previous one.

C. It restarts the app from the first screen.

D. It opens a new screen on top of the current one.

Solution

1. Step 1: Understand Navigator.push purpose

   Navigator.push adds a new screen on top of the current screen stack.

2. Step 2: Compare with other Navigator methods

   Navigator.pop removes the current screen, but push opens a new one.

3. Final Answer:

   It opens a new screen on top of the current one. -> Option D

4. Quick Check:

   Navigator.push = Open new screen [OK]

Hint: Push means add a new screen on top [OK]

Common Mistakes:

• Confusing push with pop
• Thinking push closes screens
• Assuming push restarts app

2. Which of the following is the correct syntax to open a new screen called SecondPage using Navigator.push?

easy

A. Navigator.push(SecondPage());

B. Navigator.push(context, MaterialPageRoute(builder: (context) => SecondPage()));

C. Navigator.push(context, SecondPage());

D. Navigator.push(MaterialPageRoute(SecondPage));

Solution

1. Step 1: Recall Navigator.push syntax

   Navigator.push requires context and a route, usually MaterialPageRoute with a builder function.

2. Step 2: Match syntax with options

   Navigator.push(context, MaterialPageRoute(builder: (context) => SecondPage())); correctly uses context and MaterialPageRoute with builder returning SecondPage.

3. Final Answer:

   Navigator.push(context, MaterialPageRoute(builder: (context) => SecondPage())); -> Option B

4. Quick Check:

   Correct Navigator.push syntax = Navigator.push(context, MaterialPageRoute(builder: (context) => SecondPage())); [OK]

Hint: Navigator.push needs context and MaterialPageRoute builder [OK]

Common Mistakes:

• Omitting context parameter
• Passing widget directly instead of route
• Wrong order or missing builder function

3. What will happen when the following code runs inside a button's onPressed callback?

Navigator.push(context, MaterialPageRoute(builder: (context) => SecondPage()));
Navigator.pop(context);

medium

A. The app opens SecondPage and then immediately closes it, returning to the first screen.

B. The app opens SecondPage and stays there.

C. The app crashes due to calling push and pop together.

D. Nothing happens because pop cancels push.

Solution

1. Step 1: Analyze Navigator.push call

   Navigator.push opens SecondPage on top of current screen.

2. Step 2: Analyze Navigator.pop call immediately after

   Navigator.pop closes the current screen, which is SecondPage just opened.

3. Final Answer:

   The app opens SecondPage and then immediately closes it, returning to the first screen. -> Option A

4. Quick Check:

   push then pop = open then close screen [OK]

Hint: Push adds screen, pop removes current screen [OK]

Common Mistakes:

• Assuming both happen simultaneously without effect
• Thinking pop cancels push before opening
• Believing app crashes on push-pop sequence

4. Identify the error in this code snippet that tries to open SecondPage and then close the current screen:

Navigator.push(MaterialPageRoute(builder: (context) => SecondPage()));
Navigator.pop(context);

medium

A. Missing context parameter in Navigator.push call.

B. Navigator.pop should be called before Navigator.push.

C. MaterialPageRoute cannot be used with Navigator.push.

D. SecondPage must be a StatefulWidget.

Solution

1. Step 1: Check Navigator.push parameters

   Navigator.push requires context as the first argument, missing here.

2. Step 2: Confirm other parts are correct

   MaterialPageRoute usage and pop call are correct; SecondPage widget type is unrelated.

3. Final Answer:

   Missing context parameter in Navigator.push call. -> Option A

4. Quick Check:

   Navigator.push needs context first [OK]

Hint: Navigator.push always needs context first [OK]

Common Mistakes:

• Forgetting to pass context to push
• Thinking pop order matters here
• Confusing widget type requirements

5. You want to open a new screen DetailsPage and pass back a result string when it closes. Which code correctly opens DetailsPage and waits for the result using Navigator.push and pop?

hard

A. final result = await Navigator.push(context, MaterialPageRoute(builder: (context) => DetailsPage()));
Navigator.pop(context, result);

B. Navigator.push(context, DetailsPage());
Navigator.pop(context, 'result');

C. final result = await Navigator.push(context, MaterialPageRoute(builder: (context) => DetailsPage()));
// Use result after this line

D. Navigator.pop(context);
final result = await Navigator.push(context, MaterialPageRoute(builder: (context) => DetailsPage()));

Solution

1. Step 1: Understand Navigator.push with await

   Navigator.push returns a Future that completes when the pushed screen pops with a result.

2. Step 2: Use the result after awaiting push

   final result = await Navigator.push(context, MaterialPageRoute(builder: (context) => DetailsPage())); // Use result after this line correctly awaits push and then uses the result; pop with result happens inside DetailsPage.

3. Final Answer:

   final result = await Navigator.push(context, MaterialPageRoute(builder: (context) => DetailsPage())); // Use result after this line -> Option C

4. Quick Check:

   Await push to get pop result [OK]

Hint: Await push to receive pop result from new screen [OK]

Common Mistakes:

• Calling pop immediately after push in same code
• Passing widget directly instead of route
• Not awaiting push to get result