使用样式的示例

以下文档包含使用样式创建特定类型组件的示例。

注意： 这些示例不会从主题中提取值，因为它们仅用于说明样式的功能。在项目中使用这些示例时，请将常见的可设置主题的颜色、形状和排版样式提取到主题类中。

按钮

样式可用于创建许多不同类型的按钮，这些按钮可能与标准 Material 组件不同。

基本按钮

假设有以下按钮定义，可作为不同类型按钮的基础：

@Composable
fun BaseButton(
    onClick: () -> Unit,
    modifier: Modifier = Modifier,
    style: Style = Style,
    enabled: Boolean = true,
    interactionSource: MutableInteractionSource? = remember {
        MutableInteractionSource()
    },
    content: @Composable RowScope.() -> Unit
) {
    val styleState = rememberUpdatedStyleState(interactionSource) {
        it.isEnabled = enabled
    }
    Row(
        modifier = modifier
            .semantics(properties = {
                role = Role.Button
            })
            .clickable(
                enabled = enabled,
                onClick = onClick,
                interactionSource = interactionSource,
                indication = null,
            )
            .styleable(styleState, baseButtonStyle, style),
        content = content,
        verticalAlignment = Alignment.CenterVertically
    )
}
Button.kt

悬停背景翻译按钮

如需定义一个在悬停时背景会移动的按钮，请使用以下代码：

图 1. 具有在悬停时平移的背景的按钮。

@Preview
@Composable
fun HoverButtonExample() {
    Box(
        modifier = Modifier.padding(32.dp),
        contentAlignment = Alignment.Center
    ) {
        BaseButton(
            onClick = {},
            style = Style {
                background(Color.Transparent)
                shape(RoundedCornerShape(0.dp))
                border(1.dp, Color.Black)
                contentColor(Color.Black)
                fontSize(16.sp)
                fontWeight(FontWeight.Light)
                letterSpacing(1.sp)
                contentPadding(vertical = 13.dp, horizontal = 20.dp)
                dropShadow(
                    Shadow(
                        spread = 0.dp, color = Color(0xFFFFE54C),
                        radius = 0.dp,
                        offset = DpOffset(7.dp, 7.dp)
                    )
                )
                hovered {
                    animate(tween(200)) {
                        dropShadow(
                            Shadow(
                                spread = 0.dp, color = Color(0xFFFFE54C),
                                radius = 0.dp,
                                offset = DpOffset(0.dp, 0.dp)
                            )
                        )
                    }
                }
                pressed {
                    animate(tween(200)) {
                        dropShadow(
                            Shadow(
                                spread = 0.dp, color = Color(0xFFFFE54C),
                                radius = 0.dp,
                                offset = DpOffset(0.dp, 0.dp)
                            )
                        )
                    }
                }
            }
        ) {
            BaseText("Button 52")
        }
    }
}
Examples.kt

带有阴影动画的圆形景深按钮

若要创建具有深度按压效果的按钮，该效果会在 pressed 上向上和向下平移阴影，可通过以下方式实现：

图 2. 具有深度效果的按钮，按下时会平移阴影层。

@Preview
@Composable
fun ShadowAnimationButton() {
    Box(modifier = Modifier.padding(32.dp)) {
        val density = LocalDensity.current
        val buttonStyle = Style {
            background(Color(0xFFFBEED0))
            border(2.dp, Color(0xFF422800))
            shape(RoundedCornerShape(30.dp))
            dropShadow(
                Shadow(
                    color = Color(0xFF422800), offset = DpOffset(4.dp, 4.dp),
                    radius = 0.dp, spread = 0.dp
                )
            )
            contentColor(Color(0xFF422800))
            fontWeight(FontWeight.SemiBold)
            fontSize(18.sp)
            contentPaddingHorizontal(25.dp)
            externalPadding(8.dp)
            height(50.dp)
            textAlign(TextAlign.Center)
            hovered {
                animate {
                    background(Color.White)
                }
            }
            pressed {
                animate {
                    dropShadow(
                        Shadow(
                            color = Color(0xFF422800),
                            offset = DpOffset(2.dp, 2.dp),
                            radius = 0.dp,
                            spread = 0.dp
                        )
                    )
                    translation(with(density) { 2.dp.toPx() }, with(density) { 2.dp.toPx() })
                }
            }
        }
        BaseButton(
            onClick = {},
            style = buttonStyle
        ) {
            BaseText("Button 74")
        }
    }
}
Examples.kt

具有按压动画效果的多个分层样式

以下代码创建了一个按钮，该按钮具有按下时的深度效果，并具有多个样式层，所有样式层都使用相同的 StyleState：

图 3.具有按压效果和多个样式层的按钮。

@Preview
@Composable
fun MultipleStylesButton() {
    val interactionSource = remember { MutableInteractionSource() }
    val styleState = remember(interactionSource) { MutableStyleState(interactionSource) }
    val density = LocalDensity.current

    Box(
        modifier = Modifier
            .styleable(styleState) {
                size(200.dp, 48.dp)
                externalPadding(32.dp)
            }
            .clickable(interactionSource, indication = null) {},
        contentAlignment = Alignment.Center
    ) {
        val edgeStyle = Style {
            fillSize()
            shape(RoundedCornerShape(16.dp))
            background(Color(0xFF1CB0F6))
        }

        val frontStyle = Style {
            fillSize()
            background(Color(0xFF1899D6))
            shape(RoundedCornerShape(16.dp))
            contentPadding(vertical = 12.dp, horizontal = 16.dp)
            translationY(with(density) { (-4).dp.toPx() })
            pressed {
                animate {
                    translationY(with(density) { (0).dp.toPx() })
                }
            }
        }
        Box(modifier = Modifier.semantics(properties = {
            role = Role.Button
        }).styleable(styleState, edgeStyle)) {
            Box(
                modifier = Modifier
                    .styleable(styleState, frontStyle),
                contentAlignment = Alignment.Center
            ) {
                BaseText(
                    "Button 19".toUpperCase(Locale.current),
                    style = Style {
                        contentColor(Color.White)
                        fontSize(15.sp)
                        fontWeight(FontWeight.Bold)
                        letterSpacing(0.8.sp)
                    }
                )
            }
        }
    }
}
Examples.kt