android - Jetpack compose 中带有提示文本的 TextField

Question

我想textfield用hint. jetpackcompose任何示例如何创建textfield使用jectpack？谢谢

Answer 1

你可以使用1.0.0类似的东西：

var text by remember { mutableStateOf("text") }

OutlinedTextField(
        value = text, 
        onValueChange = {
             text = it
        },
        label = { Text("Label") }
)

或者

TextField(
    value = text, 
    onValueChange = {
         text = it
    },
    label = { Text("Label") }
)

Answer 2

compose_version = '1.0.0-beta07'

使用参数placeholder显示提示

TextField(value = "", onValueChange = {}, placeholder = { Text("Enter Email") })

使用参数label显示浮动标签

TextField(value = "", onValueChange = {}, label = { Text("Enter Email") })

Answer 3

您可以创建hintTextField如下jetpackCompose代码：

@Composable
fun HintEditText(hintText: @Composable() () -> Unit) {
    val state = state { "" } // The unary plus is no longer needed. +state{""}
    val inputField = @Composable {
        TextField(
            value = state.value,
            onValueChange = { state.value = it }
        )
    }
    if (state.value.isNotEmpty()) {
        inputField()
    } else {
        Layout(inputField, hintText) { measurable, constraints ->
        val inputfieldPlacable = measurable[inputField].first().measure(constraints)
        val hintTextPlacable = measurable[hintText].first().measure(constraints)
        layout(inputfieldPlacable.width, inputfieldPlacable.height) {
                inputfieldPlacable.place(0.ipx, 0.ipx)
                hintTextPlacable.place(0.ipx, 0.ipx)
        } }
    }
}

调用@Compose函数如下：

HintEditText @Composable {
                                Text(
                                    text = "Enter Email",
                                    style = TextStyle(
                                        color = Color.White,
                                        fontSize = 18.sp
                                    )
                                )
                            }

Answer 4

Jetpack 组合版本：dev08

compose 的好处是我们可以通过组合当前的可组合函数来轻松地创建我们的小部件。

我们可以创建一个包含当前所有参数的函数TextField并添加一个 hint: String参数。

@Composable
fun TextFieldWithHint(
        value: String,
        modifier: Modifier = Modifier.None,
        hint: String,
        onValueChange: (String) -> Unit,
        textStyle: TextStyle = currentTextStyle(),
        keyboardType: KeyboardType = KeyboardType.Text,
        imeAction: ImeAction = ImeAction.Unspecified,
        onFocus: () -> Unit = {},
        onBlur: () -> Unit = {},
        focusIdentifier: String? = null,
        onImeActionPerformed: (ImeAction) -> Unit = {},
        visualTransformation: VisualTransformation? = null,
        onTextLayout: (TextLayoutResult) -> Unit = {}
) {
    Stack(Modifier.weight(1f)) {
        TextField(value = value,
                modifier = modifier,
                onValueChange = onValueChange,
                textStyle = textStyle,
                keyboardType = keyboardType,
                imeAction = imeAction,
                onFocus = onFocus,
                onBlur = onBlur,
                focusIdentifier = focusIdentifier,
                onImeActionPerformed = onImeActionPerformed,
                visualTransformation = visualTransformation,
                onTextLayout = onTextLayout)
        if (value.isEmpty()) Text(hint)
    }
}

我们可以这样使用它：

@Model
object model { var text: String = "" }
TextFieldWithHint(value = model.text, onValueChange = { data -> model.text = data },
                    hint= "Type book name or author")

这种方法的缺陷是我们将提示作为字符串传递，因此如果我们想要设置提示的样式，我们应该向TextFieldWithHint（例如hintStyle、hintModifier、hintSoftWrap、...）添加额外的参数

更好的方法是接受可组合的 lambda 而不是字符串：

@Composable
fun TextFieldWithHint(
        value: String,
        modifier: Modifier = Modifier.None,
        hint: @Composable() () -> Unit,
        onValueChange: (String) -> Unit,
        textStyle: TextStyle = currentTextStyle(),
        keyboardType: KeyboardType = KeyboardType.Text,
        imeAction: ImeAction = ImeAction.Unspecified,
        onFocus: () -> Unit = {},
        onBlur: () -> Unit = {},
        focusIdentifier: String? = null,
        onImeActionPerformed: (ImeAction) -> Unit = {},
        visualTransformation: VisualTransformation? = null,
        onTextLayout: (TextLayoutResult) -> Unit = {}
) {
    Stack(Modifier.weight(1f)) {
        TextField(value = value,
                modifier = modifier,
                onValueChange = onValueChange,
                textStyle = textStyle,
                keyboardType = keyboardType,
                imeAction = imeAction,
                onFocus = onFocus,
                onBlur = onBlur,
                focusIdentifier = focusIdentifier,
                onImeActionPerformed = onImeActionPerformed,
                visualTransformation = visualTransformation,
                onTextLayout = onTextLayout)
        if (value.isEmpty()) hint()
    }
}

我们可以这样使用它：

@Model
object model { var text: String = "" }

TextFieldWithHint(value = model.text, onValueChange = { data -> model.text = data },
            hint= { Text("Type book name or author", style = TextStyle(color = Color(0xFFC7C7C7))) })

Answer 5

    var textState by remember { mutableStateOf(TextFieldValue()) }
    var errorState by remember { mutableStateOf(false) }
    var errorMessage by remember { mutableStateOf("") }


        TextField(
            value = textState,
            onValueChange = {
                textState = it
                when {
                    textState.text.isEmpty() -> {
                        errorState = true
                        errorMessage = "Please Enter Site Code"
                    }
                    else -> {
                        errorState = false
                        errorMessage = ""
                    }
                }
            },
            isError = errorState,
            label = {
                Text(
                    text = if (errorState) errorMessage
                    else "You Hint"
                )
            },
            modifier = Modifier
                .padding(top = 20.dp, start = 30.dp, end = 30.dp)
                .fillMaxWidth())

Answer 6

如果文本为空，则label参数将显示为文本，并在键入输入时移动到文本字段上方（作为标签）：

    @Composable
    fun SearchField() {
        val (text, setText) = remember { mutableStateOf(TextFieldValue("")) }
        Box(modifier = Modifier.width(180.dp).padding(2.dp)) {
            TextField(
                modifier = Modifier.fillMaxWidth(),
                value = text,
                onValueChange = { setText(it) },
                label = { Text("quick do:") },
            )
        }
    }

Answer 7

这对我有用（我认为它比 Anas 发布的更简单，因为它使用相同的组件：

@Composable
fun TextBox(
    loginInput: LoginInput,
    hint: String = "enter value",
    color: Color = Color.LightGray,
    height: Dp = 50.dp
) {

    val state = +state { "" }
    state.value = if (loginInput.usernameEntered) loginInput.username else hint

    Surface(color = color) {
        Row {
            Container(modifier = Expanded, height = height) {
                Clip(shape = RoundedCornerShape(15.dp)) {
                    Padding(padding = 15.dp) {
                        TextField(
                            value = state.value,
                            keyboardType = KeyboardType.Text,
                            onFocus = {
                                if (!loginInput.usernameEntered)
                                    state.value = ""
                            },
                            onValueChange = {
                                loginInput.usernameEntered = true
                                loginInput.username = it
                                state.value = loginInput.username
                            }
                        )
                    }
                }
            }
        }

    }
}