设计能力接口
为平台功能定义共享契约
设计能力接口 是 CoddyKit 上的免费 Kotlin Multiplatform Academy 课时。 这是第 1 节课，共 4 节。 你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。 这是 Kotlin Multiplatform Academy 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Kotlin Multiplatform Academy 课程共包含 4 节课。
本课时的部分内容尚未翻译，以英文显示。
Some Things Are Platform-Only
Reading the battery level or device model is different on Android and iOS. Shared code still needs a clean way to ask for it. 🔋
Start With the Need, Not the API
Design from what your app actually needs. A simple interface states the capability in plain Kotlin, hiding every platform detail.
interface BatteryInfo {
fun level(): Int
}One Contract, Many Backers
The interface is a promise: anyone who implements it must supply a real battery level. Each platform fulfills that promise its own way.
Keep Methods Tiny
Expose only what callers need. A focused method like level() is far easier to implement per platform than a sprawling, do-everything interface.
Name It for the Domain
Call it BatteryInfo, not AndroidBatteryHelper. A good capability name describes the feature, never the platform behind it.
Return Plain Types
Hand back simple Kotlin types like Int or String. Plain return values keep the interface portable and free of platform classes.
fun model(): StringGroup Related Calls
If several calls belong together, gather them in one interface. Device facts like model and OS version fit naturally side by side.
interface DeviceInfo {
fun model(): String
fun osVersion(): String
}Shared Code Depends on the Type
Your common logic talks only to the interface, never to a concrete class. That keeps business rules testable and platform-agnostic.
class Banner(val info: DeviceInfo)Fakes Become Easy
Because callers depend on the interface, tests can pass a fake that returns canned values. No emulator or real device required. ✅
class FakeDeviceInfo : DeviceInfo {
override fun model() = "Pixel"
override fun osVersion() = "14"
}Avoid Leaking Platform Types
Never put a UIDevice or Android Context into the interface signature. The moment you do, shared code stops compiling on the other target.
Implementations Come Later
The contract is step one. Each platform will supply its own implementation of this interface, which you wire in separately as the next step.
Quick Check
Think about what belongs in the capability contract.
Recap
You learned to design a small, domain-named interface that states a capability, returns plain types, and keeps shared code portable and testable. 🎉
常见问题解答
「设计能力接口」课时是免费的吗？
是的 — 「设计能力接口」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 Kotlin Multiplatform Academy 课程的其余内容，请升级到 CoddyKit PRO。 Kotlin Multiplatform Academy 课程共包含 4 节课。
「设计能力接口」这节课中我会学到什么？
为平台功能定义共享契约 你通过在浏览器中直接运行的动手代码来练习 Kotlin Multiplatform Academy，全天候 AI 导师会在你学习这节课的过程中回答你的问题。
学习 Kotlin Multiplatform Academy 需要有经验吗？
无需任何先前经验。CoddyKit 上的 Kotlin Multiplatform Academy 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。 这是第 1 节课，共 4 节。
「设计能力接口」课时需要多长时间？
大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。
我能在这节 Kotlin Multiplatform Academy 课中编写并运行代码吗？
能。每节 Kotlin Multiplatform Academy 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。