Card
@Composable
fun Card(
modifier: Modifier = Modifier,
shape: Shape = MaterialTheme.shapes.medium,
backgroundColor: Color = MaterialTheme.colors.surface,
contentColor: Color = contentColorFor(backgroundColor),
border: BorderStroke? = null,
elevation: Dp = 1.dp,
content: @Composable () -> Unit
)
Card
是 Compose 中一个布局组件,我们用它可以来创造出一些类似于卡片界面,相当于一个容器,我们可以在card中放置一个composable。,我们可以使用卡片显示阴影效果。我们可以添加圆角半径的边框。
如果你是 Android 开发者,它就是CardView。
package com.example.composestudy
import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.compose.foundation.clickable
import androidx.compose.foundation.interaction.MutableInteractionSource
import androidx.compose.foundation.interaction.collectIsPressedAsState
import androidx.compose.foundation.layout.*
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.material.*
import androidx.compose.runtime.*
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.text.SpanStyle
import androidx.compose.ui.text.buildAnnotatedString
import androidx.compose.ui.text.font.FontWeight
import androidx.compose.ui.text.withStyle
import androidx.compose.ui.unit.dp
import com.example.composestudy.ui.theme.ComposestudyTheme
class MainActivity : ComponentActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContent {
ComposestudyTheme {
CardDemo()
}
}
}
}
data class ButtonState(var text: String, var textColor: Color, var buttonColor: Color)
@Composable
fun ButtonDemo() {
// 获取按钮的状态
val interactionState = remember { MutableInteractionSource() }
// 使用 Kotlin 的解构方法
val (text, textColor, buttonColor) = when {
interactionState.collectIsPressedAsState().value -> ButtonState("按钮1", Color.Red, Color.Black)
else -> ButtonState( "按钮", Color.White, Color.Red)
}
Button(
onClick = { /*TODO*/ },
interactionSource = interactionState,
elevation = null,
shape = RoundedCornerShape(50),
colors = ButtonDefaults.buttonColors(
backgroundColor = buttonColor,
),
modifier = Modifier.width(IntrinsicSize.Min).height(IntrinsicSize.Min)
) {
Text(
text = text, color = textColor
)
}
}
@Composable
fun CardDemo() {
Card(
modifier = Modifier
.fillMaxWidth()
.padding(15.dp) // 外边距
.clickable{ },
// 设置点击波纹效果,注意如果 CardDemo() 函数不在 MaterialTheme 下调用
// 将无法显示波纹效果
elevation = 10.dp // 设置阴影
) {
Column(
modifier = Modifier.padding(15.dp) // 内边距
) {
Text(
buildAnnotatedString {
append("大前端之旅 ")
withStyle(style = SpanStyle(fontWeight = FontWeight.W900, color = Color(0xFF4552B8),)
) {
append("欢迎你的到来")
}
}
)
Text(
buildAnnotatedString {
append("你现在观看的是 ")
withStyle(style = SpanStyle(fontWeight = FontWeight.W900)) {
append("Card的使用方法")
}
}
)
}
}
}
@Preview(name = "Light Mode")
@Composable
fun PreviewMessageCard() {
ComposestudyTheme {
CardDemo()
}
}
![](https://img.laitimes.com/img/__Qf2AjLwojIjJCLyojI0JCLiQDOxEzX3xCZlhXam9VbsUmepNXZy9CXwJWZ3xCdh1mcvZ2Lc1zaHRGcWdUYuVzVa9GczoVdG1mWfVGc5RHLwIzX39GZhh2csATMflHLwEzX4xSZz91ZsAzMfRHLGZkRGZkRfJ3bs92YskmNhVTYykVNQJVMRhXVEF1X0hXZ0xiNx8VZ6l2cssmch1mclRXY39CXldWYtlWPzNXZj9mcw1ycz9WL49DciV2duATO0QzN2MWM0UWNyUWOyYzX2UTNwADM3AzLcZDMyIDMy8CXn9Gbi9CXzV2Zh1WavwVbvNmLvR3YxUjLyM3Lc9CX6MHc0RHaiojIsJye.webp)
带形状的卡片:
我们可以设置卡片背景的形状。如果我们没有提供,它将采用具有 4dp 半径的 RoundedCornerShape。您可以使用以下形状,
- 矩形形状
- 圆形
- 圆角形状
- 切角形状
@Composable
fun CardWithShape() {
val paddingModifier = Modifier.padding(10.dp)
Card(shape = RoundedCornerShape(20.dp),elevation = 10.dp, modifier = paddingModifier) {
Text(text = "Round corner shape", modifier = paddingModifier)
}
}
带边框的卡片:
我们使用border属性,我们需要为border属性设置BorderStroke。BorderStroke 有两个参数,第一个是宽度大小,另一个是边框颜色。
@Composable
fun CardWithBorder() {
val paddingModifier = Modifier.padding(10.dp)
Card(
elevation = 10.dp,
border = BorderStroke(1.dp, Color.Blue),
modifier = paddingModifier
) {
Text(text = "Card with blue border", modifier = paddingModifier)
}
多视图:
卡片仅支持一种可组合功能。如果您想在同一张卡片中使用多个小部件,您应该使用其他布局组合功能,例如 Column、Row、ConstraintLayout
@Composable
fun CardWithMultipleViews() {
val paddingModifier = Modifier.padding(10.dp)
Card(
elevation = 10.dp,
modifier = paddingModifier
) {
Column(modifier = paddingModifier) {
Text(text = "First Text")
Text(text = "Second Text")
}
}
}
内容颜色:
@Composable
fun CardWithContentColor() {
val paddingModifier = Modifier.padding(10.dp)
Card(
elevation = 10.dp,
contentColor = Color.Blue,
modifier = paddingModifier
) {
Column() {
Text(text = "Text with card content color (Blue)",
modifier = paddingModifier)
Text(text = "Text with card custom color",
color = Color.Black,
modifier = paddingModifier)
}
}
}