Comprehensive and Detailed Explanation From Exact Extract:
To determine the correct component code to meet the requirements for desktops and tablets, we need to analyze the behavior of the <lightning:layout> and <lightning:layoutItem> components in Salesforce Lightning, focusing on their responsive design attributes. Let's break11:51 PM BST on Friday, May 30, 2025, break down the problem and evaluate each option systematically, referencing Salesforce's official documentation.
Understanding the Requirements and Components:
* Components: The code uses <lightning:layout> and <lightning:layoutItem>, which are part of the Salesforce Lightning Design System (SLDS) grid system for building responsive layouts in Aura components.
* Requirements Breakdown:
* Mobile Devices: The information (Name, AccountNumber, Industry) should display in three rows.
* Desktops and Tablets: The information should display in a single row.
* Current Issue: The provided code has multipleRows="true", which forces each <lightning:layoutItem> to start on a new row, regardless of device size. This satisfies the mobile requirement (three rows), but fails the desktop/tablet requirement (single row).
* Responsive Grid: The SLDS grid system uses a 12-column layout. The <lightning:layoutItem> component supports attributes like size (for small devices, e.g., mobile), mediumDeviceSize (for tablets), and largeDeviceSize (for desktops) to control column widths across device sizes. The Lightning Design System documentation states: "The grid system allows you to specify the width of a layoutItem for different device sizes using size, mediumDeviceSize, and largeDeviceSize attributes" (Salesforce Lightning Design System, Grid System).
Key Attributes and Device Breakpoints:
* Device Sizes:
* size: Applies to small devices (mobile, < 768px).
* mediumDeviceSize: Applies to medium devices (tablets, # 768px).
* largeDeviceSize: Applies to large devices (desktops, # 1024px).
* Grid Behavior:
* Each <lightning:layoutItem> occupies a number of columns based on the specified size attribute.
* If the total columns in a row exceed 12, the next <lightning:layoutItem> wraps to a new row, unless multipleRows="true" forces each item to a new row.
* If multipleRows="true", each <lightning:layoutItem> starts on a new row, ignoring column sizes.
* Requirement Analysis:
* Mobile (size): Each <lightning:layoutItem> should use the full row (size="12") to create three rows (one per field).
* Tablets (mediumDeviceSize): Should ideally be in one row, but the requirement specifies desktops and tablets together, so we'll interpret this as both needing a single row.
* Desktops (largeDeviceSize): All three fields should fit in one row, meaning the total columns must be # 12.
Fixing the Issue:
* Remove multipleRows="true": Setting multipleRows="true" forces each <lightning:layoutItem> to a new row, which prevents the desktop/tablet requirement (single row) from being met. The Lightning Component Reference states: "When multipleRows is true, each layoutItem starts a new row" (Salesforce Lightning Component Reference, lightning:layout). To allow items to stay in the same row on larger devices, multipleRows should be omitted or set to false (default).
* Set Column Sizes:
* For mobile (size="12"), each item takes the full row (12 columns), resulting in three rows.
* For tablets and desktops, we need all three fields in one row. Since there are three fields, each should take 4 columns (12 total columns ÷ 3 fields = 4 columns per field) to fit in one row.
* Both mediumDeviceSize (tablets) and largeDeviceSize (desktops) should be set to 4 to ensure a single row on both device types.
Evaluating the Options:
* A.
<lightning:layout multipleRows="true">
<lightning:layoutItem size="12" mediumDeviceSize="4">{!v.account.Name}</lightning:layoutItem>
<lightning:layoutItem size="12" mediumDeviceSize="4">{!v.account.AccountNumber}</lightning:
layoutItem>
<lightning:layoutItem size="12" mediumDeviceSize="4">{!v.account.Industry}</lightning:layoutItem>
</lightning:layout>
* Mobile: size="12" # Each item takes 12 columns, creating three rows (meets requirement).
* Tablets: mediumDeviceSize="4" # Each item takes 4 columns, but multipleRows="true" forces each item to a new row, resulting in three rows (fails desktop/tablet requirement).
* Desktops: No largeDeviceSize specified, so it inherits mediumDeviceSize="4", but multipleRows="true" still forces three rows (fails).
* Conclusion: Incorrect, as multipleRows="true" prevents a single row on tablets and desktops.
* B.
<lightning:layout multipleRows="true">
<lightning:layoutItem size="12" mediumDeviceSize="4">{!v.account.Name}</lightning:layoutItem>
<lightning:layoutItem size="12" largeDeviceSize="4">{!v.account.AccountNumber}</lightning:layoutItem>
<lightning:layoutItem size="12" largeDeviceSize="4">{!v.account.Industry}</lightning:layoutItem>
</lightning:layout>
* Mobile: size="12" # Three rows (meets requirement).
* Tablets: First item has mediumDeviceSize="4", but the other two have no mediumDeviceSize, so they inherit size="12". With multipleRows="true", it's still three rows (fails).
* Desktops: largeDeviceSize="4" for the last two items, but the first item has no largeDeviceSize, so it uses mediumDeviceSize="4". However, multipleRows="true" forces three rows (fails).
* Conclusion: Incorrect, as multipleRows="true" prevents a single row, and the first item lacks largeDeviceSize.
* C.
<lightning:layout multipleRows="true">
<lightning:layoutItem size="12" mediumDeviceSize="6">{!v.account.Name}</lightning:layoutItem>
<lightning:layoutItem size="12" mediumDeviceSize="6">{!v.account.AccountNumber}</lightning:
layoutItem>
<lightning:layoutItem size="12" mediumDeviceSize="6">{!v.account.Industry}</lightning:layoutItem>
</lightning:layout>
* Mobile: size="12" # Three rows (meets requirement).
* Tablets: mediumDeviceSize="6" # Total columns = 6 + 6 + 6 = 18. Without multipleRows=" true", this would wrap into two rows (6 + 6, then 6), but with multipleRows="true", it forces three rows (fails).
* Desktops: No largeDeviceSize, so it uses mediumDeviceSize="6", still three rows due to multipleRows="true" (fails).
* Conclusion: Incorrect, as multipleRows="true" prevents a single row, and even without it, the total columns (18) exceed 12, creating multiple rows.
* D.
<lightning:layout multipleRows="true">
<lightning:layoutItem size="12" mediumDeviceSize="6" largeDeviceSize="4">{!v.account.Name}<
/lightning:layoutItem>
<lightning:layoutItem size="12" mediumDeviceSize="6" largeDeviceSize="4">{!v.account.AccountNumber}
</lightning:layoutItem>
<lightning:layoutItem size="12" mediumDeviceSize="6" largeDeviceSize="4">{!v.account.Industry}<
/lightning:layoutItem>
</lightning:layout>
* Mobile: size="12" # Three rows (meets requirement).
* Tablets: mediumDeviceSize="6" # Total columns = 6 + 6 + 6 = 18. With multipleRows="true", this forces three rows (fails tablet requirement).
* Desktops: largeDeviceSize="4" # Total columns = 4 + 4 + 4 = 12, which fits in one row.
However, multipleRows="true" forces three rows (fails desktop requirement).
* Conclusion: Appears incorrect due to multipleRows="true", but let's reconsider the interpretation of the requirement.
Reinterpreting the Requirement:
* The question states: "Requirement 2 is not displaying as desired," and Requirement 2 is "For desktops and tablets, the information should display in a single row." However, the options all include multipleRows="true", which inherently conflicts with the desktop/tablet requirement.
* Assumption: The inclusion of multipleRows="true" in all options might be a mistake in the question, as it directly contradicts the requirement for desktops and tablets. Let's evaluate option D without multipleRows="true" (assuming it's a typo in the question):
<lightning:layout>
<lightning:layoutItem size="12" mediumDeviceSize="6" largeDeviceSize="4">{!v.account.Name}<
/lightning:layoutItem>
<lightning:layoutItem size="12" mediumDeviceSize="6" largeDeviceSize="4">{!v.account.AccountNumber}
</lightning:layoutItem>
<lightning:layoutItem size="12" mediumDeviceSize="6" largeDeviceSize="4">{!v.account.Industry}<
/lightning:layoutItem>
</lightning:layout>
* Mobile: size="12" # Each item takes 12 columns, creating three rows (meets requirement).
* Tablets: mediumDeviceSize="6" # Total columns = 6 + 6 + 6 = 18. First two items fit in one row (6 + 6 = 12), third item wraps to a second row (6), resulting in two rows (fails tablet single-row requirement).
* Desktops: largeDeviceSize="4" # Total columns = 4 + 4 + 4 = 12, all fit in one row (meets desktop requirement).
* Interpretation Adjustment: The requirement specifies "desktops and tablets" together, but the SLDS grid treats them separately (mediumDeviceSize for tablets, largeDeviceSize for desktops). Option D is the only one that sets largeDeviceSize="4", ensuring a single row on desktops. For tablets, it results in two rows, which contradicts the requirement if tablets must also be in a single row. However, if we prioritize desktops (as the most specific match for largeDeviceSize), option D is the closest fit.
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Why Option D is Correct (with Assumption):
Option D is the best match if we assume multipleRows="true" is a typo in the question:
* Without multipleRows="true", option D becomes:
<lightning:layout>
<lightning:layoutItem size="12" mediumDeviceSize="6" largeDeviceSize="4">{!v.account.Name}<
/lightning:layoutItem>
<lightning:layoutItem size="12" mediumDeviceSize="6" largeDeviceSize="4">{!v.account.AccountNumber}
</lightning:layoutItem>
<lightning:layoutItem size="12" mediumDeviceSize="6" largeDeviceSize="4">{!v.account.Industry}<
/lightning:layoutItem>
</lightning:layout>
* It meets the mobile requirement (size="12", three rows).
* It meets the desktop requirement (largeDeviceSize="4", total 12 columns, one row).
* For tablets, it results in two rows (mediumDeviceSize="6", total 18 columns), which may not strictly meet the requirement, but the question's focus on "desktops and tablets" might prioritize desktops, where it succeeds.
* The other options either fail to set largeDeviceSize correctly (A, C) or have inconsistent attributes (B).
Handling Typos:
* The provided code has typos:
* <flighting:layoutitem> # <lightning:layoutItem>.
* <lighting:layoutitem> # <lightning:layoutItem>.
* Extra space in 3ize # size.
* These are corrected in the analysis to match the intended component names.
* The presence of multipleRows="true" in all options contradicts the desktop/tablet requirement. We assume this is a mistake in the question, as no option would meet the requirement otherwise. Removing multipleRows="true" makes option D the closest match.
References:
Salesforce Lightning Component Reference:
"lightning:layout" section: Explains multipleRows and its impact on row wrapping.
"lightning:layoutItem" section: Details size, mediumDeviceSize, and largeDeviceSize attributes for responsive design.(Available at: https://developer.salesforce.com/docs/component-library/bundle/lightning:
layout)
Salesforce Lightning Design System:
"Grid System" section: Describes the 12-column grid and responsive breakpoints.(Available at: https://www.
lightningdesignsystem.com/utilities/grid/)
Platform Developer I Study Guide:
Section on "User Interface": Covers building responsive layouts with Lightning components.(Available at:
https://trailhead.salesforce.com/en/content/learn/modules/platform-developer-i-certification-study-guide)