has_one，belongs_to我做错了什么？

Question

I have Users and each user sets a Goal. So a goal belongs_to a user and a user has_one: goal. I am trying to use form_for in the view to allow the user to set their goal up.

I figured it would be like microposts (which is straight from Hartl's tutorial) just with singular instead of plural. I've looked at tutorials and questions on here for this issue and tried numerous different things and I just can't get it working.

I got the form_for actually working and apparently pointing to the correct route, but I'm getting the below error and I have no clue what it means:

undefined method `stringify_keys' for "Lose Weight":String

GoalsController

class GoalsController < ApplicationController
before_filter :signed_in_user

def create
 @goal = current_user.build_goal(params[:goal])
 if @goal.save
    redirect_to @user
 end
end

def destroy
    @goal.destroy
end

def new
    Goal.new
end

end

Goal Model

class Goal < ActiveRecord::Base
attr_accessible :goal, :pounds, :distance, :lift_weight
belongs_to :user

validates :user_id, presence: true
end

User Model

class User < ActiveRecord::Base

 has_one :goal, :class_name => "Goal"

end

_goal_form (which is a modal on the Users#show)

    <div class="modal hide fade in" id="goal" >
      <%= form_for(@goal, :url => goal_path) do |f| %>
      <div class="modal-header">
       <%= render 'shared/error_messages', object: f.object %>   
        <button type="button" class="close" data-dismiss="modal">×</button>
        <h3>What's Your Health Goal This Month?</h3>
      </div>
        <div class="modal-body">
          <center>I want to <%= select(:goal, ['Lose Weight'], ['Exercise More'], ['Eat   Better']) %> </center>
        </div>
        <div class="modal-body">
          <center>I will lose  <%= select_tag(:pounds, options_for_select([['1', 1],   ['2', 1], ['3', 1], ['4', 1], ['5', 1], ['6', 1], ['7', 1], ['8', 1], ['9', 1], ['10', 1]])) %> lbs. this month!</center>
        </div>
        <div class="modal-footer" align="center">
           <a href="#" class="btn" data-dismiss="modal">Close</a>
           <%= f.submit "Set Goal", :class => "btn btn-primary" %>
        </div>
  <% end %>
</div>

Routes.rb

  resource  :goal,               only: [:create, :destroy, :new]

Answer 1

try this

# in your user model
accepts_nested_attributes_for :goal

write above code in your user model, and

for select tag try to use from this link

http://shiningthrough.co.uk/Select-helper-methods-in-Ruby-on-Rails

Answer 2

I expect the stringify_keys error is down to the way you've listed your options in the goal field, they need to be grouped up to be treated as one argument.

Along with using accepts_nested_attributes_for :goal as suggested by Dipak, you will want to have a nested form.

form_for @user do |form|
  fields_for @goal do |fields|
    fields.select :goal, ['Lose Weight', 'Exercise More', 'Eat Better']

The save action is now in the context of a user, so the attributes that come through will include a portion for the goal fields:

user =>{goal_attributes => {:goal => 'Eat Better'}}

You can save these attributes by updating the user:

@user.update_attributes(params[:user])

As an aside, your "new" action should be @goal = Goal.new , just creating a new goal does nothing, you need to assign it to a variable for it to make it to the page.

Good luck!