Aligning Elements Inside a Fluid Row: A Deep Dive

In this article, we will explore the challenges of aligning elements within a fluid row in Shiny applications. We will examine common issues and discuss potential solutions.

Understanding Fluid Rows

A fluid row is a layout element that automatically adapts to the available width of its parent container. This allows for dynamic layouts that adjust to changing screen sizes or window widths.

Common Issues with Fluid Rows

While fluid rows offer flexibility, they can also introduce challenges when working with multiple elements within them. Two common issues that arise include:

Unaligned Elements: When hiding or showing elements inside a fluid row, the alignment of other elements within the same row is affected.
Inconsistent Widths: When elements are added to or removed from a fluid row dynamically, their widths can become inconsistent, leading to visual misalignment.

Solving the Problem: A Custom Approach

The original question posed by the user highlighted these challenges. The provided solution utilizes a custom approach to address these issues.

Solution Overview

To align elements inside a fluid row while hiding certain elements, we need to consider two key factors:

Dynamic Width Adjustment: We must adjust the widths of remaining elements within the fluid row after an element has been hidden or shown.
Aligning Remaining Elements: To maintain alignment within the fluid row, we need to ensure that the widths of the remaining elements are consistent.

Solution Implementation

The provided solution utilizes a combination of Shiny’s insertUI and shinyjs libraries to create a dynamic layout that adjusts to changing user permissions.

Here’s an excerpt from the provided code snippet:

# login section
shinyauthr::loginUI(id = "login"),
# Row to add buttons after login
fluidRow(align = 'center',
         div(id = 'add_buttons')
        )

Key Components of the Solution

Conditional Rendering: The solution uses conditional rendering (if-else statements) to display different sets of elements based on the user’s permissions.
Dynamic Width Adjustment: When an element is hidden, its corresponding width property is adjusted using JavaScript code.
Aligning Remaining Elements: To maintain alignment within the fluid row, the widths of remaining elements are set consistently.

Example Use Cases

The provided solution can be applied to various scenarios where dynamic layouts and conditional rendering are necessary.

library(shiny)
library(shinyauthr)

# User base data
user_base <- tibble::tibble(
  user = c("user1", "user2", "user3"),
  password = sapply(c("pass1", "pass2", "pass3"), sodium::password_store),
  permissions = c("admin", "standard", "Basic"),
  name = c("User One", "User Two", "User Three")
)

# Number of buttons per user
num_buttons <- data.frame(
  user1 = 4,
  user2 = 3,
  user3 = 2
)

ui <- fluidPage(
  shinyjs::useShinyjs(),
  
  # Login section
  shinyauthr::loginUI(id = "login"),
  
  # Row to add buttons after login
  fluidRow(align = 'center',
           div(id = 'add_buttons')
          )
)

Example 2: Dashboard with Conditional Panels

library(shiny)
library(shinyjs)

# User base data
user_base <- tibble::tibble(
  user = c("user1", "user2", "user3"),
  password = sapply(c("pass1", "pass2", "pass3"), sodium::password_store),
  permissions = c("admin", "standard", "Basic"),
  name = c("User One", "User Two", "User Three")
)

# Number of panels per user
num_panels <- data.frame(
  user1 = 4,
  user2 = 3,
  user3 = 2
)

ui <- fluidPage(
  shinyjs::useShinyjs(),
  
  # Login section
  shinyauthr::loginUI(id = "login"),
  
  # Row to add panels after login
  fluidRow(align = 'center',
           div(id = 'add_panels')
          )
)

Conclusion

Aligning elements inside a fluid row can be challenging, especially when dealing with dynamic layouts and conditional rendering. By understanding the common issues that arise and implementing custom solutions using Shiny’s insertUI and shinyjs libraries, developers can create responsive and user-friendly interfaces.

Best Practices for Aligning Elements in Fluid Rows

Use a consistent layout structure to maintain alignment within fluid rows.
Adjust widths dynamically using JavaScript code when elements are added or removed from the row.
Use conditional rendering (if-else statements) to display different sets of elements based on user permissions.

By following these best practices and implementing custom solutions, developers can overcome common challenges associated with aligning elements inside fluid rows.

Last modified on 2025-03-02