Question

有关ruby类中方法顺序的规则是什么。看一下Michael Hartl的Rails教程中的这个例子。以下代码片段在create方法调用micropost_params方法的情况下工作得很好。但是，私有方法首先列在文件的底部。

    class MicropostsController < ApplicationController
  before_action :signed_in_user
  before_action :correct_user,   only: :destroy

  def create
    @micropost = current_user.microposts.build(micropost_params)
    if @micropost.save
      flash[:success] = "Micropost created!"
      redirect_to root_url
    else
      @feed_items = []
      render 'static_pages/home'
    end
  end

  def destroy
    @micropost.destroy
    redirect_to root_url
  end

  private

    def micropost_params
      params.require(:micropost).permit(:content)
    end

    def correct_user
      @micropost = current_user.microposts.find_by(id: params[:id])
      redirect_to root_url if @micropost.nil?
    end
end

然而，我现在正在尝试编写的代码给了我一个no方法错误。据推测，这是因为由于代码中的位置，该方法尚未定义。也许还有另一种解释。请指教。

class WeatherModel

    def self.getWeatherProjections(field_names)
        @tablename = "myProjections"
        getWeatherData(field_names)
    end

    def self.getWeatherDailyAct(field_names)
        @tablename = "WeatherDaily"
        #getWeatherData(field_names)
    end

    def self.getWeatherHourlyAct(field_names)
        @tablename = "WeatherHourly"
        #getWeatherData(field_names)
    end

    private

    def getWeatherData(field_names)
        if isActive? && (not field_names.nil?)
            if not field_names.empty?
                field_names.inject("field_names[0].to_s") { |set,name| set+="{#{name},"}
            else
                set="*"
            end

             @client.execute("SELECT #{set} FROM [#{table_name}]")
        else
            init
        end
    end

    def init
        @client = TinyTds::Client.new username: 'blah', password: 'blah', host: 'blah', database: 'blah'
    end

    def isActive?
        @client.active?
    end

end

可能是因为我没有计算得到一些类/实例方法的细节。 self.method可以不调用实例方法吗？请有人解释一下这个谜团。哦，我得到的错误是：

2.1.4 :006 >   WeatherModel.getWeatherProjections([])
NoMethodError: undefined method `getWeatherData' for WeatherModel:Class
    from /Users/forresce/Dev/guc_scadagas_rails/app/models/weather_model.rb:5:in `getWeatherProjections'

NoMethodError：未定义的方法

0 个答案: