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TextField 与 OutlinedTextField

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TextField 与 OutlinedTextField 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。

Why Text Fields Matter

Almost every app asks the user to type something. In Compose, the TextField is your gateway to reading that input. ✏️

The TextField Composable

A TextField shows an editable box. It needs a current value and a callback that fires every time the text changes.

TextField(
    value = name,
    onValueChange = { name = it }
)

State Drives the Value

The field never stores text itself. You hold it in state and feed it back in, so the UI always shows the latest value.

var name by remember { mutableStateOf("") }

onValueChange Closes the Loop

Each keystroke calls onValueChange with the new text. You save it to state, Compose redraws, and the field reflects what was typed.

onValueChange = { newText -> name = newText }

Meet OutlinedTextField

OutlinedTextField works exactly the same way, but draws a clean border around the input instead of a filled background.

OutlinedTextField(
    value = name,
    onValueChange = { name = it }
)

Filled vs Outlined

The filled TextField has a shaded box and underline. The outlined one is lighter and airier. They behave identically, so pick by style.

Add a Label

A label tells the user what the field is for. It floats above the text once the field is focused or filled.

OutlinedTextField(
    value = name,
    onValueChange = { name = it },
    label = { Text("Name") }
)

Single Line by Default

Set singleLine to true to keep input on one row. The keyboard then shows a Done action instead of a newline.

TextField(
    value = name,
    onValueChange = { name = it },
    singleLine = true
)

Read the Value Anywhere

Because the text lives in state, any other Composable can read it. Greet the user the moment they finish typing their name. 👋

Text("Hello, " + name)

It Is a Controlled Field

Compose fields are controlled: what you display is whatever you pass as value. Forget to update state and the field appears frozen.

Start Simple, Grow Later

A value plus an onValueChange is all you truly need. Labels, icons, and validation are extras you add on top.

Quick Check

Which parameter receives the user's new text on every keystroke?

Recap

You met TextField and OutlinedTextField: bind a value from state, update it in onValueChange, and add a label. That is text input in Compose. 🎉

常见问题解答

「TextField 与 OutlinedTextField」课时是免费的吗？

是的 — 「TextField 与 OutlinedTextField」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。

「TextField 与 OutlinedTextField」这节课中我会学到什么？

读取用户输入的内容。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。

「TextField 与 OutlinedTextField」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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