SelectionContainer.kt
/*
* Copyright 2019 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.ui.selection
import androidx.compose.runtime.Composable
import androidx.compose.runtime.DisposableEffect
import androidx.compose.runtime.Providers
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.setValue
import androidx.compose.ui.Modifier
import androidx.compose.ui.composed
import androidx.compose.ui.gesture.dragGestureFilter
import androidx.compose.ui.gesture.noConsumptionTapGestureFilter
import androidx.compose.ui.layout.onGloballyPositioned
import androidx.compose.ui.platform.AmbientClipboardManager
import androidx.compose.ui.platform.AmbientHapticFeedback
import androidx.compose.ui.platform.AmbientTextToolbar
import androidx.compose.ui.text.InternalTextApi
/**
* Enables text selection for it's direct or indirection children.
*
* @sample androidx.compose.ui.samples.SelectionSample
*/
@Suppress("DEPRECATION")
@OptIn(InternalTextApi::class)
@Composable
fun SelectionContainer(modifier: Modifier = Modifier, content: @Composable () -> Unit) {
var selection by remember { mutableStateOf<Selection?>(null) }
SelectionContainer(
modifier = modifier,
selection = selection,
onSelectionChange = {
selection = it
},
children = content
)
}
/**
* Disables text selection for it's direct or indirection children. To use this, simply add this
* to wrap one or more text composables.
*
* @sample androidx.compose.ui.samples.DisableSelectionSample
*/
@Composable
fun DisableSelection(content: @Composable () -> Unit) {
Providers(
AmbientSelectionRegistrar provides null,
content = content
)
}
/**
* Selection Composable.
*
* The selection composable wraps composables and let them to be selectable. It paints the selection
* area with start and end handles.
*/
@Suppress("ComposableLambdaParameterNaming")
@OptIn(InternalTextApi::class)
@Deprecated("Please use SelectionContainer with no callback")
@InternalTextApi
@Composable
fun SelectionContainer(
/** A [Modifier] for SelectionContainer. */
modifier: Modifier = Modifier,
/** Current Selection status.*/
selection: Selection?,
/** A function containing customized behaviour when selection changes. */
onSelectionChange: (Selection?) -> Unit,
children: @Composable () -> Unit
) {
val registrarImpl = remember { SelectionRegistrarImpl() }
val manager = remember { SelectionManager(registrarImpl) }
manager.hapticFeedBack = AmbientHapticFeedback.current
manager.clipboardManager = AmbientClipboardManager.current
manager.textToolbar = AmbientTextToolbar.current
manager.onSelectionChange = onSelectionChange
manager.selection = selection
val selectionContainerModifier = Modifier.composed {
val gestureModifiers = Modifier.noConsumptionTapGestureFilter { manager.onRelease() }
val positionedModifier = remember {
// Get the layout coordinates of the selection container. This is for hit test of
// cross-composable selection.
Modifier.onGloballyPositioned { manager.containerLayoutCoordinates = it }
}
if (selection != null) {
this.then(gestureModifiers).then(positionedModifier)
} else {
this.then(positionedModifier)
}
}
Providers(AmbientSelectionRegistrar provides registrarImpl) {
// Get the layout coordinates of the selection container. This is for hit test of
// cross-composable selection.
SimpleLayout(
modifier = modifier.then(selectionContainerModifier)
) {
children()
manager.selection?.let {
for (isStartHandle in listOf(true, false)) {
SelectionHandle(
startHandlePosition = manager.startHandlePosition,
endHandlePosition = manager.endHandlePosition,
isStartHandle = isStartHandle,
directions = Pair(it.start.direction, it.end.direction),
handlesCrossed = it.handlesCrossed,
modifier = Modifier.dragGestureFilter(
manager.handleDragObserver(
isStartHandle
)
),
handle = null
)
}
}
}
}
DisposableEffect(manager) {
onDispose {
manager.selection = null
manager.hideSelectionToolbar()
}
}
}