R shiny sizing boxes

Question

My problem is that I told shiny to take all the line (12 columns) to print c7 box but it only uses half of it. Can anyone figure out what is the problem? Following is my code:

 library(shinydashboard)
 library(shiny)
 library(readr)
 library(rsconnect)
 header=dashboardHeader(title="App")
 sidebar=dashboardSidebar(sidebarMenu(
 menuItem("Stack", tabName = "a", icon = icon("dashboard"))))
 c7=column(12,box(title="Prediction Box",status="warning",solidHeader=FALSE,
            textInput("text", label = h3("Write something :"), value = ""),actionButton("do","Go")))
 body=dashboardBody(tabItems(tabItem(tabName="a",fluidRow(c7))))
 ui <- dashboardPage(header,sidebar,body)

 server <- function(input, output){
 }
shinyApp(ui,server) 

Answer 1

By default, if you're not specifying the width of the box it will be set to 6. Have a look at ?box

E.g.:

library(shinydashboard)
library(shiny)

header=dashboardHeader(title="App")
sidebar=dashboardSidebar(sidebarMenu(menuItem("Stack", tabName = "a", icon = icon("dashboard"))))

?box
c7=column(12,box(width=12,title="Prediction Box",status="warning",solidHeader=FALSE,
                 textInput("text", label = h3("Write something :"), value = ""),actionButton("do","Go")))


body=dashboardBody(tabItems(tabItem(tabName="a",fluidRow(c7))))
ui <- dashboardPage(header,sidebar,body)

server <- function(input, output){
}
shinyApp(ui,server)