Forms update output before submit button shiny R - r

Question

My form automatically updates the output before I press the Submit button. I read the description of "Submit" button and it says "Forms that include a submit button do not automatically update their outputs when inputs change, rather they wait until the user explicitly clicks the submit button". I am not sure if there's anything wrong.
For your information, here is my code. Data is from UCI (adult data)
Server.R
library(shiny)
library(caret)
predictSalary <- function(input){
adultData <- read.table("adult.data", header = FALSE, sep = ",", strip.white = TRUE)
adultName <- read.csv("adult.name.csv", header = FALSE, sep = ",", stringsAsFactors = FALSE)
names(adultData) <- adultName[, 1]
#Only select several attributes
selected <- c("age", "education", "marital.status", "relationship", "sex", "hours.per.week", "salary")
#selected <- c("age", "hours.per.week", "salary")
adultData <- subset(adultData, select = selected)
#The data is big, we only take 20% for the training
trainIndex = createDataPartition(adultData$salary, p=0.20, list=FALSE)
training = adultData[ trainIndex, ]
set.seed(33833)
modFit <- train(salary ~ ., method = "rpart", data=training)
predict(modFit, newdata = input)
}
shinyServer(
function(input, output) {
dataInput <- reactive({
age <- input$age
edu <- as.factor(input$edu)
marritalstat <- input$marritalstat
relationship <- input$relationship
sex <- input$sex
hours <- input$hours
data.frame(age = age,
education = edu,
marital.status = marritalstat,
relationship = relationship,
sex = sex,
hours.per.week = hours)
# age <- input$age
# hours <- input$hours
# data.frame(age = age, hours.per.week = hours)
})
# dat <- c(input$age, input$edu, input$marritalstat,
# input$relationship, input$sex, input$hours)
output$prediction <- renderPrint({predictSalary(dataInput())})
}
)
Ui.R
library(shiny)
shinyUI(
pageWithSidebar(
# Application title
headerPanel("Salary prediction"),
sidebarPanel(
numericInput('age', 'Age', 40, min = 17, max = 90, step = 1),
selectInput('edu', 'Education',
c("Bachelors"="Bachelors",
"Some-college"="Some-college",
"11th"="11th",
"HS-grad"="HS-grad",
"Prof-school"="Prof-school",
"Assoc-acdm"="Assoc-acdm",
"Assoc-voc"="Assoc-voc",
"9th"="9th",
"7th-8th"="7th-8th",
"12th"="12th",
"Masters"="Masters",
"1st-4th"="1st-4th",
"10th"="10th",
"Doctorate"="Doctorate",
"5th-6th"="5th-6th",
"Preschool"="Preschool")),
radioButtons('marritalstat', 'Marrital Status',
c("Married-civ-spouse" = "Married-civ-spouse",
"Divorced" = "Divorced",
"Never-married" = "Never-married",
"Separated" = "Separated",
"Widowed" = "Widowed",
"Married-spouse-absent" = "Married-spouse-absent",
"Married-AF-spouse" = "Married-AF-spouse")),
radioButtons('relationship', 'Relationship',
c("Wife" = "Wife",
"Own-child" = "Own-child",
"Husband" = "Husband",
"Not-in-family" = "Not-in-family",
"Other-relative" = "Other-relative",
"Unmarried" = "Unmarried")),
radioButtons('sex', 'Sex', c("Male", "Female")),
numericInput('hours', 'Hours per week', 40, min = 1, max = 99, step = 1),
submitButton('Submit')
),
mainPanel(
h3('Results of prediction'),
h4('The predicted salary is '),
verbatimTextOutput("prediction"),
h3('Prediction of salary'),
p('The application is designed to predict whether somebodys salary is greater or smaller than 50k.
The data is extracted from the adult data, provided by UCI database. In order to predict a salary, users need to
provide information of the person whom they would like to make prediction on. After filling in necessary information,
users will press "Submit". The information includes:'),
p(' - Age: must be from 17 to 90'),
p(' - Education'),
p(' - Marital status'),
p(' - Relationship'),
p(' - Gender'),
p(' - Total work hours per week: must be from 1 to 99')
)
)
)

Answer 1

I found the solution by using actionButton in replacement of submitButton. However, I think that there must be an ideal solution with using submitButton.