Substitutability is a principle in object-oriented programming stating that, in a computer program, if S is a subtype of T, then objects of type T may be replaced with objects of type S (i.e. an object of type T may be substituted with any object of a subtype S) without altering any of the desirable properties of the program (correctness, task performed, etc.). More formally, the Liskov substitution principle (LSP) is a particular definition of a subtyping relation, called (strong) behavioral subtyping, that was initially introduced by Barbara Liskov in a 1987.
The Liskov Substitution Principle is the third of Robert C. Martin’s SOLID design principles. It extends the Open/Closed principle and enables you to replace objects of a parent class with objects of a subclass without breaking the application. This requires all subclasses to behave in the same way as the parent class.
“Functions that use pointers or references to base classes must be able to use objects of derived classes without knowing it.” – Robert C. Martin
A violation of this behaviour would imply your code is not SOLID and it may be prone to malfunctioning.
Google used to publish Apps almost instantly, no quality review whatsoever, as result, the Google Play Store was full of garbage. Crappy Apps, malicious Apps and overall useless Apps were rampant. Several scandals and privacy breaches after, Google said, no more… “We will review the Apps and ensure some quality across the board”, (turns out that, although criticized, Apple was right, all the time).
material.io is a free, no trick, easy grab, palette tool that will allow you compose your color harmony for Android and iOS in a very simplistic way.
This website is based on Material Design, which is a design language developed by Google. Very popular across the board.
https://material.io/resources/color here you may find a large array of colors and easily generate primaryColor, primaryLightColor, primaryDarkColor, secondaryColor, primaryTextColor, etc.
On top of that, it will allow you to download straightaway a colors.xml or colors.xml file with all the constants well defined, which is pretty convenient. Ready to drop into your Android Studio or XCode project.
where Swift is overtaking Objective-C rapidly and the momentum is clear. In the
Android world, presently, the language option is not that clear.
Yes, Kotlin is
there, new, coming forward, garden-fresh, 21-century ready but it isn’t ultimately
taking off, not as expected.
Kotlin was first
introduced by JetBrains in 2011, which is the creator of IntelliJ IDEA,
PyCharm, and many other top IDEs. It got its name from ‘Kotlin Island’ in St.
Petersburg, Russia. Made to strike Java.
That said, the
dominance of Java is still immense, the number of libraries, APIs, code
generally speaking is humongous. Not to mention the readability of it, the many
algorithms and things done or thought already in Java, yeah… Simple as it
sounds, it’s hard to break a solid present for a “uncertain” bright future.