Ruby TK how to receive input from user?

Question

I am new to Ruby and I would like to receive input from users with Ruby TK. The Internet has too little information about this. So I am here to search for a solution. Below is the current method that I am using.

TkSpinbox.new(left) do
    to 100
    from 1
    value = TkVariable.new()
    increment value += 1
    command (proc{
        puts value
    })
    pack("side" => "bottom",  "padx"=> "50", "pady"=> "54")
end

I have no idea how to get the value inside the spinbox and return it to another place. This is the screenshot of the GUI.

Answer 1

There are a couple of little changes you can make to that code snippet which will let you access the spinbox value correctly:

1. The increment method takes one argument, the amount to increment the value by every time you click a button. So you can replace increment value += 1 with just increment 1.

2. You don't need the value = TkVariable.new() line, because the TkSpinbox keeps track of its value itself. (If you did want to set an initial value, you would use e.g. self.value = 10.)

After making those changes, this is the final code snippet:

TkSpinbox.new(left) do
    to 100
    from 1
    increment 1

    # Equivalent to your proc({...}) usage here, but this is better Ruby style
    command do
        puts value
    end
    pack("side" => "bottom",  "padx"=> "50", "pady"=> "54")
end

And here's how it looks when you click the increment button several times:

To use the value from some other control like a button, you can assign your TkSpinbox to a variable and access its value from another command block:

# Assign spinbox to a variable named `spinbox`
spinbox = TkSpinbox.new(left) do
    to 100
    from 1
    increment 1
    command do
        puts value
    end
    pack("side" => "bottom",  "padx"=> "50", "pady"=> "54")
end

TkButton.new(left) do
    text "Do something with the value"
    command do
        # Now `spinbox` is usable from other controls
        # (The value may be a string, so we use .to_i to convert to an integer)
        puts spinbox.value.to_i * 100
    end
    pack("side" => "top")
end