| /* |
| * 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.ui.core.demos.gestures |
| |
| import androidx.compose.Composable |
| import androidx.compose.emptyContent |
| import androidx.compose.state |
| import androidx.ui.core.Alignment |
| import androidx.ui.core.DensityAmbient |
| import androidx.ui.core.Modifier |
| import androidx.ui.core.gesture.ScrollCallback |
| import androidx.ui.core.gesture.scrollGestureFilter |
| import androidx.ui.core.gesture.scrollorientationlocking.Orientation |
| import androidx.compose.foundation.Box |
| import androidx.compose.foundation.Text |
| import androidx.compose.ui.geometry.Offset |
| import androidx.compose.ui.graphics.Color |
| import androidx.compose.foundation.layout.Column |
| import androidx.compose.foundation.layout.fillMaxSize |
| import androidx.compose.foundation.layout.offset |
| import androidx.compose.foundation.layout.preferredSize |
| import androidx.compose.foundation.layout.wrapContentSize |
| import androidx.ui.unit.Dp |
| import androidx.ui.unit.dp |
| |
| /** |
| * Simple demo that shows off ScrollGestureFilter. |
| */ |
| @Composable |
| fun ScrollGestureFilterDemo() { |
| Column { |
| Text("Demonstrates scroll orientation locking") |
| Text( |
| "The inner box is composed inside of the outer. If you start dragging the inner box" + |
| "vertically, it will drag vertically , the same pointer will only ever allow " + |
| "the box to be dragged vertically. If drag the inner box horizontally, the " + |
| "container will start being dragged horizontally and that pointer will only " + |
| "ever drag horizontally." |
| ) |
| ScrollableBox(240.dp, Orientation.Horizontal, Green, Yellow) { |
| ScrollableBox(144.dp, Orientation.Vertical, Red, Blue) |
| } |
| } |
| } |
| |
| @Composable |
| fun ScrollableBox( |
| size: Dp, |
| orientation: Orientation, |
| activeColor: Color, |
| idleColor: Color, |
| children: @Composable () -> Unit = emptyContent() |
| ) { |
| |
| val color = state { idleColor } |
| val offsetPx = state { 0f } |
| |
| val offsetDp = with(DensityAmbient.current) { |
| offsetPx.value.toDp() |
| } |
| |
| val scrollCallback: ScrollCallback = object : ScrollCallback { |
| override fun onStart(downPosition: Offset) { |
| color.value = activeColor |
| } |
| |
| override fun onScroll(scrollDistance: Float): Float { |
| offsetPx.value += scrollDistance |
| return scrollDistance |
| } |
| |
| override fun onStop(velocity: Float) { |
| color.value = idleColor |
| } |
| |
| override fun onCancel() { |
| color.value = idleColor |
| } |
| } |
| |
| val (offsetX, offsetY) = when (orientation) { |
| Orientation.Horizontal -> offsetDp to Dp.Hairline |
| Orientation.Vertical -> Dp.Hairline to offsetDp |
| } |
| |
| Box( |
| Modifier.offset(offsetX, offsetY) |
| .fillMaxSize() |
| .wrapContentSize(Alignment.Center) |
| .scrollGestureFilter(scrollCallback, orientation) |
| .preferredSize(size), |
| backgroundColor = color.value |
| ) { |
| children() |
| } |
| } |