/*
* Copyright 2022 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.compose.material3
import androidx.compose.animation.core.MutableTransitionState
import androidx.compose.foundation.interaction.Interaction
import androidx.compose.foundation.interaction.MutableInteractionSource
import androidx.compose.foundation.layout.ColumnScope
import androidx.compose.foundation.layout.PaddingValues
import androidx.compose.runtime.Composable
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.TransformOrigin
import androidx.compose.ui.platform.LocalDensity
import androidx.compose.ui.unit.DpOffset
import androidx.compose.ui.unit.dp
import androidx.compose.ui.window.Popup
import androidx.compose.ui.window.PopupProperties
/**
* Material Design dropdown menu.
*
* Menus display a list of choices on a temporary surface. They appear when users interact with a
* button, action, or other control.
*
* 
*
* A [DropdownMenu] behaves similarly to a [Popup], and will use the position of the parent layout
* to position itself on screen. Commonly a [DropdownMenu] will be placed in a [Box] with a sibling
* that will be used as the 'anchor'. Note that a [DropdownMenu] by itself will not take up any
* space in a layout, as the menu is displayed in a separate window, on top of other content.
*
* The [content] of a [DropdownMenu] will typically be [DropdownMenuItem]s, as well as custom
* content. Using [DropdownMenuItem]s will result in a menu that matches the Material
* specification for menus. Also note that the [content] is placed inside a scrollable [Column],
* so using a [LazyColumn] as the root layout inside [content] is unsupported.
*
* [onDismissRequest] will be called when the menu should close - for example when there is a
* tap outside the menu, or when the back key is pressed.
*
* [DropdownMenu] changes its positioning depending on the available space, always trying to be
* fully visible. It will try to expand horizontally, depending on layout direction, to the end of
* its parent, then to the start of its parent, and then screen end-aligned. Vertically, it will
* try to expand to the bottom of its parent, then from the top of its parent, and then screen
* top-aligned. An [offset] can be provided to adjust the positioning of the menu for cases when
* the layout bounds of its parent do not coincide with its visual bounds. Note the offset will
* be applied in the direction in which the menu will decide to expand.
*
* Example usage:
* @sample androidx.compose.material3.samples.MenuSample
*
* @param expanded whether the menu is expanded or not
* @param onDismissRequest called when the user requests to dismiss the menu, such as by tapping
* outside the menu's bounds
* @param offset [DpOffset] to be added to the position of the menu
*/
@Suppress("ModifierParameter")
@Composable
fun DropdownMenu(
expanded: Boolean,
onDismissRequest: () -> Unit,
modifier: Modifier = Modifier,
offset: DpOffset = DpOffset(0.dp, 0.dp),
properties: PopupProperties = PopupProperties(focusable = true),
content: @Composable ColumnScope.() -> Unit
) {
val expandedStates = remember { MutableTransitionState(false) }
expandedStates.targetState = expanded
if (expandedStates.currentState || expandedStates.targetState) {
val transformOriginState = remember { mutableStateOf(TransformOrigin.Center) }
val density = LocalDensity.current
val popupPositionProvider = DropdownMenuPositionProvider(
offset,
density
) { parentBounds, menuBounds ->
transformOriginState.value = calculateTransformOrigin(parentBounds, menuBounds)
}
Popup(
onDismissRequest = onDismissRequest,
popupPositionProvider = popupPositionProvider,
properties = properties
) {
DropdownMenuContent(
expandedStates = expandedStates,
transformOriginState = transformOriginState,
modifier = modifier,
content = content
)
}
}
}
/**
* Material Design dropdown menu item.
*
* Menus display a list of choices on a temporary surface. They appear when users interact with a
* button, action, or other control.
*
* 
*
* Example usage:
* @sample androidx.compose.material3.samples.MenuSample
*
* @param text text of the menu item
* @param onClick called when this menu item is clicked
* @param modifier the [Modifier] to be applied to this menu item
* @param leadingIcon optional leading icon to be displayed at the beginning of the item's text
* @param trailingIcon optional trailing icon to be displayed at the end of the item's text. This
* trailing icon slot can also accept [Text] to indicate a keyboard shortcut.
* @param enabled controls the enabled state of this menu item. When `false`, this component will
* not respond to user input, and it will appear visually disabled and disabled to accessibility
* services.
* @param colors [MenuItemColors] that will be used to resolve the colors used for this menu item in
* different states. See [MenuDefaults.itemColors].
* @param contentPadding the padding applied to the content of this menu item
* @param interactionSource the [MutableInteractionSource] representing the stream of [Interaction]s
* for this menu item. You can create and pass in your own `remember`ed instance to observe
* [Interaction]s and customize the appearance / behavior of this menu item in different states.
*/
@Composable
fun DropdownMenuItem(
text: @Composable () -> Unit,
onClick: () -> Unit,
modifier: Modifier = Modifier,
leadingIcon: @Composable (() -> Unit)? = null,
trailingIcon: @Composable (() -> Unit)? = null,
enabled: Boolean = true,
colors: MenuItemColors = MenuDefaults.itemColors(),
contentPadding: PaddingValues = MenuDefaults.DropdownMenuItemContentPadding,
interactionSource: MutableInteractionSource = remember { MutableInteractionSource() },
) {
DropdownMenuItemContent(
text = text,
onClick = onClick,
modifier = modifier,
leadingIcon = leadingIcon,
trailingIcon = trailingIcon,
enabled = enabled,
colors = colors,
contentPadding = contentPadding,
interactionSource = interactionSource,
)
}