Android 按钮上的下拉列表单击“撰写”

如何在单击按钮时创建下拉菜单项。在喷气背包里

如此处所示，但对于按钮：

      DropdownMenu(
            expanded = expanded,
            onDismissRequest = { expanded = false },
            toggle = iconButton,
            dropdownOffset = Position(24.dp, 0.dp),
            toggleModifier = modifier
        ) {
            options.forEach {
                DropdownMenuItem(onClick = {}) {
                    Text(it)
                }
            }
        }

---

您可以使用以下内容：

   var expanded by remember { mutableStateOf(false) }

   Button(onClick = { expanded = true }){
        Text ("...")
    }
    DropdownMenu(
        expanded = expanded,
        onDismissRequest = { expanded = false },
        //....
    ) {
        items.forEachIndexed { index, s ->
            //....
        }
    }

---

您可以使用以下内容：

   var expanded by remember { mutableStateOf(false) }

   Button(onClick = { expanded = true }){
        Text ("...")
    }
    DropdownMenu(
        expanded = expanded,
        onDismissRequest = { expanded = false },
        //....
    ) {
        items.forEachIndexed { index, s ->
            //....
        }
    }

---

前面的答案是正确的，但缺少关键部分。下拉菜单和打开它的按钮都被包装在框中。只有这样，打开按钮才会用作菜单的锚定按钮。 这是我的版本：

@Composable
fun DropdownMenu(
    colorSelected: Color = scColors.primary,
    colorBackground: Color = scColors.onSurface,
    expanded: Boolean,
    selectedIndex: Int,
    items: List<String>,
    onSelect: (Int) -> Unit,
    onDismissRequest: () -> Unit,
    content: @Composable () -> Unit
) {
    Box {
        content()
        DropdownMenu(
            expanded = expanded,
            onDismissRequest = onDismissRequest,
            modifier = Modifier
                .height(300.dp)
                .fillMaxWidth()
                .background(
                    color = colorBackground,
                    shape = RoundedCornerShape(16.dp)
                )
        ) {
            items.forEachIndexed { index, s ->
                if (selectedIndex == index) {
                    DropdownMenuItem(
                        modifier = Modifier
                            .fillMaxWidth()
                            .background(
                                color = colorSelected,
                                shape = RoundedCornerShape(16.dp)
                            ),
                        onClick = { onSelect(index) }
                    ) {
                        Text(
                            text = s,
                            color = Color.Black,
                            textAlign = TextAlign.Center,
                            modifier = Modifier.fillMaxWidth()
                        )
                    }
                } else {
                    DropdownMenuItem(
                        modifier = Modifier.fillMaxWidth(),
                        onClick = { onSelect(index) }
                    ) {
                        Text(
                            text = s,
                            color = Color.DarkGray,
                            textAlign = TextAlign.Center,
                            modifier = Modifier.fillMaxWidth()
                        )
                    }
                }
            }
        }
    }
}

---

前面的答案是正确的，但缺少关键部分。下拉菜单和打开它的按钮都被包装在框中。只有这样，打开按钮才会用作菜单的锚定按钮。 这是我的版本：

@Composable
fun DropdownMenu(
    colorSelected: Color = scColors.primary,
    colorBackground: Color = scColors.onSurface,
    expanded: Boolean,
    selectedIndex: Int,
    items: List<String>,
    onSelect: (Int) -> Unit,
    onDismissRequest: () -> Unit,
    content: @Composable () -> Unit
) {
    Box {
        content()
        DropdownMenu(
            expanded = expanded,
            onDismissRequest = onDismissRequest,
            modifier = Modifier
                .height(300.dp)
                .fillMaxWidth()
                .background(
                    color = colorBackground,
                    shape = RoundedCornerShape(16.dp)
                )
        ) {
            items.forEachIndexed { index, s ->
                if (selectedIndex == index) {
                    DropdownMenuItem(
                        modifier = Modifier
                            .fillMaxWidth()
                            .background(
                                color = colorSelected,
                                shape = RoundedCornerShape(16.dp)
                            ),
                        onClick = { onSelect(index) }
                    ) {
                        Text(
                            text = s,
                            color = Color.Black,
                            textAlign = TextAlign.Center,
                            modifier = Modifier.fillMaxWidth()
                        )
                    }
                } else {
                    DropdownMenuItem(
                        modifier = Modifier.fillMaxWidth(),
                        onClick = { onSelect(index) }
                    ) {
                        Text(
                            text = s,
                            color = Color.DarkGray,
                            textAlign = TextAlign.Center,
                            modifier = Modifier.fillMaxWidth()
                        )
                    }
                }
            }
        }
    }
}

---

不知道您想要实现什么，但是参数切换可以用于您想要的任何东西。因此，如果您想要一个常规按钮而不是图标按钮，只需将其替换为

toggle={button（onClick={setExpanded（！expanded）}{Text（“Open Dropdown”）}

。我希望这对您有所帮助。不知道您想要实现什么，但参数切换可以用于任何您想要的。因此，如果您想要一个常规按钮而不是图标按钮，只需将其替换为

toggle={button（onClick={setExpanded（！expanded）}{Text（“Open Dropdown”）}

。我希望这对你有帮助。