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.Providers
import androidx.compose.runtime.remember
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.onGloballyPositioned
import androidx.compose.ui.platform.ClipboardManagerAmbient
import androidx.compose.ui.platform.HapticFeedBackAmbient
import androidx.compose.ui.platform.TextToolbarAmbient
import androidx.compose.ui.text.InternalTextApi
/**
* Selection Composable.
*
* The selection composable wraps composables and let them to be selectable. It paints the selection
* area with start and end handles.
*/
@OptIn(InternalTextApi::class)
@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 = HapticFeedBackAmbient.current
manager.clipboardManager = ClipboardManagerAmbient.current
manager.textToolbar = TextToolbarAmbient.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(SelectionRegistrarAmbient 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
)
}
SelectionFloatingToolBar(manager = manager)
}
}
}
}
/**
* This is for disabling selection for text when the text is inside a SelectionContainer.
*
* To use this, simply add this to wrap one or more text composables.
*/
@Composable
fun DisableSelection(content: @Composable () -> Unit) {
Providers(
SelectionRegistrarAmbient provides null,
children = content
)
}
@Composable
private fun SelectionFloatingToolBar(manager: SelectionManager) {
manager.showSelectionToolbar()
}