前言

此篇博客讲解Button按钮

一个简单的例子

快速了解一下

效果图

代码

@Composable
fun APage() {
    Column(
        Modifier.fillMaxSize(),
        horizontalAlignment = Alignment.CenterHorizontally,
        verticalArrangement = Arrangement.Center
    ) {
        Button(onClick = {
            //点击回调
            Toast.makeText(this@DemoActivity, "点击按钮", Toast.LENGTH_SHORT).show()
        }) {
            //单单一个Button是没有内容的，这里需要在Button里添加一个Text
            Text(text = "点击")
        }
    }
}

参数详解

@OptIn(ExperimentalMaterialApi::class)
@Composable
fun Button(
    onClick: () -> Unit,    //点击回调
    modifier: Modifier = Modifier,//修饰符
    enabled: Boolean = true,    //是否启用点击
    interactionSource: MutableInteractionSource = remember { MutableInteractionSource() }, //交互状态信息(用来实现选中效果、按下效果等等)
    elevation: ButtonElevation? = ButtonDefaults.elevation(),   //阴影效果
    shape: Shape = MaterialTheme.shapes.small,      //自定义形状
    border: BorderStroke? = null,                   //按键边框
    colors: ButtonColors = ButtonDefaults.buttonColors(),   //背景色
    contentPadding: PaddingValues = ButtonDefaults.ContentPadding,  //内边距
    content: @Composable RowScope.() -> Unit            //Button这个父类容器的内容，注意它是横向的
)

设置按键启用状态与按键背景颜色

效果图

代码

@Composable
fun APage() {
    //启用状态
    val isEnabled = remember {
        mutableStateOf(true)
    }
    //按键颜色
    val buttonColors = ButtonDefaults.buttonColors(
        backgroundColor = Color.Red, //背景颜色
        contentColor = Color.Yellow, //内容颜色
        disabledBackgroundColor = Color.DarkGray,  //未启用按键背景色
        disabledContentColor = Color.Black   //未启用按键内容色
    )
    Column(
        Modifier.fillMaxSize(),
        horizontalAlignment = Alignment.CenterHorizontally,
        verticalArrangement = Arrangement.Center
    ) {
        Button(onClick = {
            Toast.makeText(this@DemoActivity, "点击", Toast.LENGTH_SHORT).show()
        }, enabled = isEnabled.value, colors = buttonColors) {
            Text(text = "点击")
        }
        Button(onClick = { isEnabled.value = !isEnabled.value }) {
            Text(text = "设置上面的按键是否启用")
        }
    }
}

按键状态(按下效果实现)

效果图

代码

@Composable
fun APage() {
    //点击状态来源
    val interactionSource =  remember { MutableInteractionSource() }
    //interactionSource.collectIsPressedAsState() 为按下状态
    //interactionSource.collectIsFocusedAsState() 为焦点选中状态
    //interactionSource.collectIsHoveredAsState() 为鼠标悬停状态
    //interactionSource.collectIsDraggedAsState() 为拖动状态

    val buttonColors = if (interactionSource.collectIsPressedAsState().value) {
        ButtonDefaults.buttonColors(
            backgroundColor = Color.Gray, //背景颜色
            contentColor = Color.White, //内容颜色
        )
    } else {
        ButtonDefaults.buttonColors(
            backgroundColor = Color.Cyan, //背景颜色
            contentColor = Color.Black, //内容颜色
        )
    }
    Column(
        Modifier.fillMaxSize(),
        horizontalAlignment = Alignment.CenterHorizontally,
        verticalArrangement = Arrangement.Center
    ) {
        Button(onClick = {
            Toast.makeText(this@DemoActivity, "点击", Toast.LENGTH_SHORT).show()
        }, colors = buttonColors, interactionSource = interactionSource) {
            Text(text = "点击")
        }
    }
}

end