• [development experience] safe value of function / nested map in flutter


    DART’s null judgment Dart language has provided a lot of grammar sugar to improve the writing method of judging null value, but there are two situations that are not easy to judge judgefunctionIs it empty In this case, you often need to write code like this: Problem code Function(String) filter; //Must write an if, actually […]

  • Onload in the list of vant list will be triggered twice, resulting in repeated data in the list. The solution is as follows


    1. Sometimes when the network request is very slow, the data may still be on the road and the request is not finished. As a result, if you re-enter and request again, the list data will be repeated (in fact, the data with page = 1 has been requested twice) 2. Solution: let the back-end […]

  • Introduction of Huawei Cloud Architecture production tool – freedgo


    What is Huawei cloud? Huawei cloud provides you with ICT cloud computing services as convenient and efficient as tap water, rich in cloud host, cloud server, cloud database and cloud computing products, and completes the whole process of application development, deployment, online and operation efficiently and conveniently. []( https://www.freedgo.com/publi… “What is the composition of Huawei […]

  • Avoided redundant navigation to current location


    This error is encountered in the Vue project, which does not affect the function, but the console will report this error when pushing: vue-router.esm.js?fe87:1958 Uncaught (in promise) NavigationDuplicated: Avoided redundant navigation to current location: “/Home”. After searching online for a long time, almost all of them said that there was a problem with the version […]

  • Precautions for avoiding pit in spark streaming


    Two RDDS cannot be nested: Caused by: org.apache.spark.SparkException: RDD transformations and actions can only be invoked by the driver, not inside of other transformations; for example, rdd1.map(x => rdd2.values.count() * x) is invalid because the values transformation and count action cannot be performed inside of the rdd1.map transformation. For more information, see SPARK-5063. Solution: convert […]

  • C # various file extensions


    .cs: Class moduleCode file. Business logic processing layer code. .sln:Solution fileTo provide solution explorer with the information needed to display the graphical interface of management files. .csproj:Project documentsTo create information about references, data connections, folders, and files needed by the application. .aspx:Dynamic web suffix(Expand: JSP, PHP). (static web page suffixes, such as: HTML, shtml, XML, […]

  • Glide exception: failed to find generated appglidemodule solution


    situation The app uses glide to load network pictures. In the stable version of the app, many pictures could not be loaded. After investigation, except for the pictures cached by glide framework, other pictures were triggered Glide.onError Exception is Failed to find GeneratedAppGlideModule. You should include an annotationProcessor compile dependency on com.github.bumptech.glide:compiler in your application […]

  • Six JavaScript user authentication libraries in 2019


    Source: official account, front-end full stack developer. “Build a user authentication system for me in two weeks” is a common sentence in the R & D team. For various reasons, this task has been left to a developer in the team to solve. On the one hand, you really don’t want to waste a lot […]

  • The problem of file upload progress display in react native


    The daily article series is used to record the problems encountered in daily work and life and possible (unsolved) solutions, not limited to technology. problem One of the problems encountered and solved today is how to display the upload progress bar when uploading files in react native describe There are many solutions for uploading files […]

  • Redis mind map


    Frequently asked questions What are the functions of redis? Data cache function The function of distributed lock Support data persistence Support services Support message queuing Why is redis single threaded? Because CPU is not the bottleneck of redis, the bottleneck of redis is most likely machine memory or network bandwidth. Since single thread is easy […]

  • oracle ORA-31655


    The ora-31655 error occurs Reason: it is not the same schema that causes problems   Solution: Add remap at the end of the import statement_ schema= old:new This means that old is the original schema, that is, the exported user name, and new is the user name you want to import For example: here is […]

  • Warning not scoped to the top level: root element appears when swiper is introduced


    After introducing swiper into the project, we found that many warnings similar to the following appeared in the console warning in ./node_modules/swiper/css/swiper.css Module Warning (from ./node_modules/postcss-loader/src/index.js): Warning (429:3) Custom property ignored: not scoped to the top-level :root element (.swiper-lazy-preloader-black { … –swiper-preloader-color: … }) @ ./node_modules/swiper/css/swiper.css 4:14-135 14:3-18:5 15:22-143 @ ./node_modules/cache-loader/dist/cjs.js??ref–12-0!./node_modules/babel-loader/lib!./node_modules/cache-loader/dist/cjs.js??ref–0-0!./node_modules/vue-loader/lib??vue-loader-options!./src/views/payment/pay.vue?vue&type=script&lang=js& @ ./src/views/payment/pay.vue?vue&type=script&lang=js& @ ./src/views/payment/pay.vue […]