Programmer Think

1, State Hook 1,useState State Hook is a function used in function components (useState), which is used to use state in function components useState The function has a parameter whose value represents the default value of the stateThe return value of the function is an array, which must contain two items Item 1: value of current stat ...

Service startup process -- Based on Android 11 Recently, when reviewing the relevant knowledge points of Android system, we all know that Android has four components: Activity, Service, Broadcast Receive and Content Provider. Compared with other knowledge points, the best way to review the four components is to follow the source code again. Wh ...

Why is setContentView familiar? Because this method is a method we have been in contact with since we started Android development. It is found in every Activity we have written. But why is setContentView strange? Because we only know how to use it in our daily development, and we don't deeply analyze how this method turns the layout resource id ...

  catalogue What is a device manager? The function of dev under Linux Devfs sysfs kobject udev proc What is a device manager? The device manager is responsible for managing the peripherals on this computer. When we insert a keyboard and mouse through the USB port provided by the computer, the device manager will communicate with it t ...

preface Some time ago, a new employee came to the company. He said that the new employee had been outsourcing code for one and a half years before he came to our company. Once I chatted with him about List. I casually asked him how to solve the unsafe multi-threaded concurrency of List collection when outsourcing. Unexpectedly, he looked at me ...

This blog post is a note taken when learning the C + + video of dark horse programmer. It is only convenient to review the old and know the new. It is not used for other purposes. 1, string container 1.1 basic concept of string 1. Essence: String is a C + + style string, and string is essentially a class 2. The difference between string ...

Introduction to software package management Software package classification Source package The source package needs to be compiled into binary package before installation, so the installation is slow. There is also a special package called script installation package in the source package. This package does not need to be installed manua ...

JWT overview Json Web Token (JWT) is a JSON based open standard implemented to transfer declarations between network application environments. The declaration of JWT is generally used to transfer the authenticated user identity information between identity providers and service providers, so as to obtain resources from the resource serv ...

Nginx sets the virtual directory through alias. In the configuration of nginx, the alias directory is different from the root directory: 1) The directory specified by alias is accurate, that is, the files in the path directory accessed by location matching are directly found in the alias directory; 2) The directory specified by root is the ...

Concept of polymorphism 1 Generally speaking, it is a variety of forms. Specifically, it is to complete a certain behavior. When different objects complete it, they will produce different states. 2 Definition and implementation of polymorphism 2.1 composition conditions of polymorphism Polymorphic conditions are introduced with the help ...