Programmer Think

1, Foreword In SparseArray detailed explanation and source code analysis, we are familiar with the basic usage, characteristics and implementation principle of SparseArray. There is also an equally important data structure ArrayMap in the toolkit of the Android SDK. Its purpose is to replace HashMap when the amount of data is small, such as hu ...

Appearance mode: also known as "facade mode", it belongs to structural design mode. It is one of the relatively simple, common and widely used design modes. The main purpose is to simplify client requests by providing delegate calls to methods in existing systems definition If the external wants to communicate with the internal, it ...

This article mainly shares the usage and differences of Kotlin's scope functions let, run, with, apply and also. During the execution of scope function, a temporary scope is formed through lambda expression, which can reduce the number of some logic codes. Context object: this or it this run, with, and apply reference context objects wi ...

Here comes the squid game. Now let's start. Let's see what level you've passed. Without the aid of IDE, see whether your human flesh compiler can compile the correct results. Scala-like functions fun hello() = { println("Hello, World") } hello() a). Does not compile b). Prints "Hello, World" c). Nothing d). Something el ...

Preliminary study on design mode Singleton mode Variables are defined internally and judged by closures. If they do not exist, new variables are generated Strategy mode Consistent with the principle of single responsibilityAdd or reduce strategies without major changes to the original codeThere are many ways to deal with the same ...

catalogue Singleton design pattern Introduction to single example design mode Eight ways of single case design mode Hungry Han formula (static constant) Hungry Chinese (static code block) Lazy (thread unsafe) Lazy (thread safety, synchronization method) Lazy (thread safe, synchronous code block) Static inner class enumeration Source ...

Note source: Shang Silicon Valley Java design pattern (illustration + framework source code analysis) Interpreter mode 1. Four arithmetic problems Four operations are realized through the interpreter mode, such as calculating the value of a + b - c. specific requirements 1) First enter the form of the expression, such as a + b + c - d + e. t ...

Note source: Shang Silicon Valley Java design pattern (illustration + framework source code analysis) Strategy mode 1. Duck problem Prepare the duck project, and the specific requirements are as follows: 1) There are ducks (such as wild ducks, Peking ducks, water ducks, etc. ducks have various behaviors, such as barking, flying, etc.) 2) Dis ...

1, Singleton mode 1. Applicable scenarios Only 1 object is required for the project 2. Advantages and disadvantages &Advantages: (1) Reduce memory expenses. For frequently used objects, they are always created and destroyed, which takes up a lot of memory (2) Reduce the performance overhead. When the generation of an object requires mo ...

Scenario: when some data needs to be received and processed in our project, because they come from different channels (such as Alibaba and Tencent), different channels need different processing methods. Let's write a common Demo to realize the scenario. 1. First, build an abstract class of basic rules, GeneralChannelRule, and define an abstrac ...