由于 ProMotion / RedPotion 的一些非常奇怪的行为，过去几周我一直在失去理智。
我已将奇怪的行为缩小为 ProMotion 的生命周期方法和 API 调用看似无序的执行。
我有一个屏幕，它将从我的 API 获取信息并根据从 API 返回的图像 url 显示图像。我将我的项目过度简化为屏幕、模型和样式表，如下所示：
测试屏幕：
class TestScreen < PM::Screen
title "Your title here"
stylesheet TestScreenStylesheet
def on_load
mp "ran on_load"
@face_image = append!(UIImageView, :face_image)
mp "getting data from API"
Face.get(1) do |response, face|
if response.success?
mp "face returned from API:"
mp face.inspect
@face = face
else
@face = [{attributes: {name: "No faces found"}}]
end
end
mp "should have printed data obtained from API"
end
def will_appear
mp "ran on_will_appear"
mp "face in will_appear:"
if @face
rmq(:face_image).attr(remote_image: @face.picture)
else
mp "@face is nil!!!"
end
end
end
样式表：
class TestScreenStylesheet < ApplicationStylesheet
def setup
end
def root_view(st)
st.background_color = color.white
end
def face_image(st)
st.frame = {l: 30, t: 140, w: 250, h: 250}
st.placeholder_image = image.resource("placeholder_image.png")
end
end
模型：
class Face
attr_accessor :id, :name, :description, :local_description, :picture, :bio_picture, :star_ranking, :status, :facetype_id, :answers
def initialize(response)
@id = response[:data][0][:id]
@name = response[:data][0][:attributes][:name]
@description = response[:data][0][:attributes][:description]
@local_description = response[:data][0][:attributes][:local_description]
@picture = response[:data][0][:attributes][:picture]
@bio_picture = response[:data][0][:attributes][:bio_picture]
@star_ranking = response[:data][0][:attributes][:star_ranking]
@status = response[:data][0][:attributes][:status]
@facetype_id = response[:data][0][:attributes][:facetype_id]
@answers = response[:data][0][:attributes][:answers]
end
def self.get(category_id,&callback)
ApiClient.client.get "random_face?mycategory=#{category_id}" do |response|
model = nil
if response.success?
model = self.new(response.object)
end
callback.call(response, model)
end
end
end
我已经放置了打印输出命令（mp），这样我就可以弄清楚什么时候执行了，正如你从下面的结果中看到的那样，一切都出了问题：
"ran on_load"
"getting data from API"
"should have printed data obtained from API"
"ran on_will_appear"
"face in will_appear:"
"@face is nil!!!"
"face returned from API:"
"#<Face:0x113c37c90 @id=\"1\" @name=\"Leonel Messi\" @description=\"Leonel Messi es un jugador portugués de fútbol, 4 veces ganador del Balón de Oro\" @local_description=\"translation missing: en.Leonel Messi_description\" @picture=\"default_url\" @bio_picture=\"default_url\" @star_ranking=1 @status=\"active\" @facetype_id=nil @answers=\"[\\\"Kun Aguero\\\", \\\"Nicolas Shevchenko\\\", \\\"Leonel Messi\\\", \\\"Clarence Seedorf\\\"]\">"
正如预期的那样，on_load 方法首先触发，但位于 on_load 方法中间的 API 调用最后触发。因此，我尝试在 view_did_load 方法中设置的图像属性为 nil 并且失败。
我来自 Rails 背景，而且我是 RubyMotion / ProMotion / RedPotion 的新手，所以我可能对这一切都错了，但这里似乎有些地方很不对劲。