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pointerInput 与 detectTapGestures

检测点击、双击和长按。

pointerInput 与 detectTapGestures 是 CoddyKit 上的免费 Jetpack Compose 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 Jetpack Compose Academy 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Jetpack Compose 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。

The Gateway to Touch

To handle raw touch in Compose you reach for the pointerInput modifier. It gives any element a place to read finger events directly. 👆

Add It to Any Composable

Attach pointerInput in a Modifier chain. Inside its lambda you get a gesture scope where you can listen for taps, drags, and more.

Box(Modifier.pointerInput(Unit) {
  // gesture detectors go here
})

Detect Simple Taps

The friendliest helper is detectTapGestures. It bundles tap, double tap, long press, and press into one tidy call for you.

detectTapGestures(onTap = { /* tapped */ })

A Single Quick Tap

The onTap lambda fires when a finger presses and lifts without moving much. It receives the Offset where the tap landed.

detectTapGestures(onTap = { offset -> println(offset) })

Catch a Double Tap

Pass onDoubleTap to react to two quick taps in a row. It is perfect for a like or zoom shortcut on an image. 💙

detectTapGestures(onDoubleTap = { /* zoom in */ })

Hold for Long Press

The onLongPress lambda fires after the finger stays down past a threshold. Use it to open context menus or selection mode.

detectTapGestures(onLongPress = { /* show menu */ })

Track the Press Itself

Use onPress to know the moment a finger touches down. Its lambda is suspendable, so you can await release or cancellation.

detectTapGestures(onPress = { awaitRelease() })

Every Tap Carries Position

Each tap callback hands you an Offset in pixels, measured from the top-left of the composable. Read it to know exactly where the user touched.

The Key Argument Matters

The first argument to pointerInput is a key. When it changes the gesture block restarts, so pass any state your handlers depend on.

Modifier.pointerInput(enabled) { /* restarts if enabled flips */ }

Gestures Run in Coroutines

The pointerInput block is a suspend scope. That is why detectors can await events frame by frame without blocking the UI thread.

Combine Several Callbacks

One detectTapGestures call can take tap, double tap, and long press together. Compose figures out which one the user meant.

detectTapGestures(onTap = {...}, onLongPress = {...})

Quick Check

Which helper bundles tap, double tap, and long press into one call?

Recap: Raw Taps Made Easy

You met pointerInput and detectTapGestures for tap, double tap, and long press. They are your foundation for custom touch handling. 🎉

常见问题解答

「pointerInput 与 detectTapGestures」课时是免费的吗？

是的 — 「pointerInput 与 detectTapGestures」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 Jetpack Compose Academy 课程的其余内容，请升级到 CoddyKit PRO。 Jetpack Compose Academy 课程共包含 4 节课。

「pointerInput 与 detectTapGestures」这节课中我会学到什么？

检测点击、双击和长按。你通过在浏览器中直接运行的动手代码来练习 Jetpack Compose 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 Jetpack Compose Academy 需要有经验吗？

无需任何先前经验。CoddyKit 上的 Jetpack Compose 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。

「pointerInput 与 detectTapGestures」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 Jetpack Compose Academy 课中编写并运行代码吗？

能。每节 Jetpack Compose 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。

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