Question

是否有办法将外围延伸点贴上顶(延伸)的标签,当外线延伸区不集中时,仍然有地主?

在Xml布局中,我们有“扩大”的特性。

Answer 1

目前,<代号>持有人/代码>适用<代码>alpha>/code> 更改这一条件InputPhase。就业——和;如果(showLabel) 0f otherwise 1f ,则有一定参数实现<代码>expandHintEnabled的相同行为。

A workaround can be to use a visualTransformation to display a placeholder when the text is empty, removing the placeholder parameter.

类似:

    val textColor = if (text.isEmpty())
        MaterialTheme.colors.onSurface.copy(ContentAlpha.medium)
    else
        LocalContentColor.current.copy(LocalContentAlpha.current)

    val textStyle = if (text.isEmpty())
        LocalTextStyle.current.merge(MaterialTheme.typography.subtitle1)
    else
        LocalTextStyle.current

    TextField(
        value = text,
        onValueChange = { text = it },
        //placeholder = { Text("Placeholder") },
        label = { Text("Label") },
        visualTransformation = if (text.isEmpty())
            PlaceholderTransformation("Placeholder")
        else VisualTransformation.None,
        textStyle = textStyle,
        colors = TextFieldDefaults.textFieldColors(
            textColor = textColor
        )
    )

注

class PlaceholderTransformation(val placeholder: String) : VisualTransformation {
    override fun filter(text: AnnotatedString): TransformedText {
        return PlaceholderFilter(text, placeholder)
    }
}

fun PlaceholderFilter(text: AnnotatedString, placeholder: String): TransformedText {

    val numberOffsetTranslator = object : OffsetMapping {
        override fun originalToTransformed(offset: Int): Int {
            return 0
        }

        override fun transformedToOriginal(offset: Int): Int {
            return 0
        }
    }

    return TransformedText(AnnotatedString(placeholder), numberOffsetTranslator)
}

友情链接