| /* |
| * 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.animation.demos |
| |
| import android.util.Log |
| import androidx.compose.Composable |
| import androidx.compose.getValue |
| import androidx.compose.remember |
| import androidx.compose.setValue |
| import androidx.compose.state |
| import androidx.compose.animation.Crossfade |
| import androidx.ui.core.Modifier |
| import androidx.ui.core.gesture.tapGestureFilter |
| import androidx.compose.foundation.Box |
| import androidx.compose.ui.graphics.Color |
| import androidx.compose.foundation.layout.Column |
| import androidx.compose.foundation.layout.Row |
| import androidx.compose.foundation.layout.fillMaxSize |
| import androidx.compose.foundation.layout.preferredHeight |
| import androidx.ui.unit.dp |
| import kotlin.random.Random |
| |
| @Composable |
| fun CrossfadeDemo() { |
| var current by state { tabs[0] } |
| Column { |
| Row { |
| tabs.forEach { tab -> |
| Box( |
| Modifier.tapGestureFilter(onTap = { |
| Log.e("Crossfade", "Switch to $tab") |
| current = tab |
| }) |
| .weight(1f, true) |
| .preferredHeight(48.dp), |
| backgroundColor = tab.color |
| ) |
| } |
| } |
| Crossfade(current = current) { tab -> |
| tab.lastInt = remember { Random.nextInt() } |
| Box(Modifier.fillMaxSize(), backgroundColor = tab.color) |
| } |
| } |
| } |
| |
| private val tabs = listOf( |
| Tab(Color(1f, 0f, 0f)), |
| Tab(Color(0f, 1f, 0f)), |
| Tab(Color(0f, 0f, 1f)) |
| ) |
| |
| private data class Tab(val color: Color) { |
| var lastInt: Int = 0 |
| set(value) { |
| if (value != field) { |
| Log.e("Crossfade", "State recreated for $color") |
| field = value |
| } |
| } |
| } |