| /* |
| * 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.state |
| import androidx.ui.core.Alignment |
| import androidx.ui.core.Direction |
| import androidx.ui.core.Modifier |
| import androidx.ui.core.gesture.dragSlopExceededGestureFilter |
| import androidx.compose.foundation.Box |
| import androidx.compose.foundation.Text |
| import androidx.compose.ui.graphics.Color |
| import androidx.compose.foundation.layout.Column |
| import androidx.compose.foundation.layout.fillMaxSize |
| import androidx.compose.foundation.layout.preferredSize |
| import androidx.compose.foundation.layout.wrapContentSize |
| import androidx.ui.unit.dp |
| |
| /** |
| * Simple [dragSlopExceededGestureFilter] demo. |
| */ |
| @Composable |
| fun DragSlopExceededGestureFilterDemo() { |
| |
| val verticalColor = Color(0xfff44336) |
| val horizontalColor = Color(0xff2196f3) |
| |
| val orientationVertical = state { true } |
| |
| // This would be more efficient if onTouchSlopExceeded were memoized because it's |
| // value doesn't need to change for each new composition. Like this, every time |
| // we recompose, a new lambda is created. Here we aren't memoizing to demonstrate |
| // that TouchSlopExceededGestureDetector behaves correctly when it is recomposed |
| // because onTouchSlopExceeded changes. |
| val onTouchSlopExceeded = |
| { |
| orientationVertical.value = !orientationVertical.value |
| } |
| |
| val canDrag = |
| if (orientationVertical.value) { |
| { direction: Direction -> |
| when (direction) { |
| Direction.UP -> true |
| Direction.DOWN -> true |
| else -> false |
| } |
| } |
| } else { |
| { direction: Direction -> |
| when (direction) { |
| Direction.LEFT -> true |
| Direction.RIGHT -> true |
| else -> false |
| } |
| } |
| } |
| |
| val color = |
| if (orientationVertical.value) { |
| verticalColor |
| } else { |
| horizontalColor |
| } |
| |
| Column { |
| Text( |
| "Demonstrates functionality of Modifier.dragSlopExceededGestureFilter, which calls " + |
| "its callback when touch slop has been exceeded by the average distance" + |
| " change of all pointers. This also demonstrates controlling which" + |
| " directions can be dragged to exceed touch slop." |
| ) |
| Text( |
| "When red, a drag on the box will turn the box blue only when you drag up or down on" + |
| " the screen. When blue, a drag on the box will turn the box red when you" + |
| " drag to the right or left." |
| ) |
| Box( |
| Modifier.fillMaxSize() |
| .wrapContentSize(Alignment.Center) |
| .preferredSize(192.dp) |
| .dragSlopExceededGestureFilter(onTouchSlopExceeded, canDrag), |
| backgroundColor = color |
| ) |
| } |
| } |