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Showing posts from August, 2026

Observer Pattern: The Hidden Magic Behind Flutter State Management

When I first started learning state management in Flutter, it honestly felt like magic. I'd change one variable, call setState , and the screen would just… update. Later I met ValueNotifier and ValueListenableBuilder , and it got even stranger — now only one widget would rebuild while everything around it stayed perfectly still. I hadn't written any code to watch for changes. I hadn't wired anything up. It just worked. And anything that "just works" without me understanding why makes me a little uncomfortable. So I did what any curious developer does: I went down the rabbit hole. I wanted to know how a value "knows" when to tell the UI to rebuild. Who is listening? How does the change travel from my variable to the pixels on screen? That question led me to something much bigger than Flutter — a classic software design pattern called the Observer pattern . Once I understood it, the magic didn't disappear. It just turned into some...
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Observer Pattern: The Hidden Magic Behind Flutter State Management

When I first started learning state management in Flutter, it honestly felt like magic. I'd change one variable, call setState , and the screen would just… update. Later I met ValueNotifier and ValueListenableBuilder , and it got even stranger — now only one widget would rebuild while everything around it stayed perfectly still. I hadn't written any code to watch for changes. I hadn't wired anything up. It just worked. And anything that "just works" without me understanding why makes me a little uncomfortable. So I did what any curious developer does: I went down the rabbit hole. I wanted to know how a value "knows" when to tell the UI to rebuild. Who is listening? How does the change travel from my variable to the pixels on screen? That question led me to something much bigger than Flutter — a classic software design pattern called the Observer pattern . Once I understood it, the magic didn't disappear. It just turned into some...
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Keep Your Promises: The Liskov Substitution Principle Made Simple

If you're learning clean code, you'll keep running into the "SOLID" principles. The L stands for the Liskov Substitution Principle (LSP) — a scary name for a genuinely simple idea. This guide starts from zero, so no prior knowledge is needed. What it is The Liskov Substitution Principle says: If something is supposed to work like a certain type, then any "version" of that type must be able to take its place without causing problems. That's the whole thing. If you call something a Doctor , it has to actually behave like a doctor everywhere a doctor is expected. If you call something an ApiClient , it has to behave like one everywhere. Break that, and your program fails — usually later, in a confusing way. The principle is named after Barbara Liskov, a computer scientist who described it back in 1987. But you don't need the academic version to use it well. First, what does "substitute" mean? This is the word that makes the whole pr...
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