Question

我想用textfield中的hint文本创建jetpackcompose。有任何示例如何使用textfield创建jectpack吗？谢谢

Answer 1

通过1.0.0-alpha01，您可以使用类似的内容：

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

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

或

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

Answer 2

您可以像以下代码一样在hintTextField中创建jetpackCompose：

@Composable
fun HintEditText(hintText: @Composable() () -> Unit) {
    val state = +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，如下所示：

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

Answer 3

Jetpack撰写版本：dev08

compose的好处是我们可以通过组合当前的可组合函数轻松地创建小部件。

我们只需创建一个具有当前TextField的所有参数的函数，然后添加一个 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")

此方法的陷阱是我们将提示作为字符串传递，因此，如果我们要对提示进行样式设置，则应在TextFieldWithHint中添加额外的参数（例如，hintStyle，hintModifier，hintSoftWrap等）。 / p>

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 4

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 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

这是对我有用的东西（我认为这比Anas发布的内容要简单一些，因为它使用的是相同的组件：

@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
                            }
                        )
                    }
                }
            }
        }

    }
}

Answer 7

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

    @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:") },
            )
        }
    }

Jetpack中带有提示文本的TextField组成

7 个答案: