| /* |
| * 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.foundation.demos |
| |
| import androidx.compose.Composable |
| import androidx.compose.Providers |
| import androidx.compose.getValue |
| import androidx.compose.remember |
| import androidx.compose.setValue |
| import androidx.compose.state |
| import androidx.ui.core.Modifier |
| import androidx.ui.demos.common.ComposableDemo |
| import androidx.compose.foundation.Box |
| import androidx.compose.foundation.ContentColorAmbient |
| import androidx.compose.foundation.ContentGravity |
| import androidx.compose.foundation.lazy.LazyColumnItems |
| import androidx.compose.foundation.Text |
| import androidx.compose.foundation.clickable |
| import androidx.compose.foundation.currentTextStyle |
| import androidx.compose.foundation.lazy.LazyRowItems |
| import androidx.compose.foundation.shape.corner.RoundedCornerShape |
| import androidx.compose.ui.graphics.Color |
| import androidx.compose.foundation.layout.Column |
| import androidx.compose.foundation.layout.Row |
| import androidx.compose.foundation.layout.fillMaxHeight |
| import androidx.compose.foundation.layout.padding |
| import androidx.compose.foundation.layout.preferredWidth |
| import androidx.ui.unit.dp |
| import androidx.ui.unit.sp |
| import kotlin.random.Random |
| |
| val LazyListDemos = listOf( |
| ComposableDemo("Simple column") { LazyColumnDemo() }, |
| ComposableDemo("Add/remove items") { ListAddRemoveItemsDemo() }, |
| ComposableDemo("Horizontal list") { LazyRowItemsDemo() } |
| ) |
| |
| @Composable |
| private fun LazyColumnDemo() { |
| LazyColumnItems( |
| items = listOf( |
| "Hello,", "World:", "It works!", "", |
| "this one is really long and spans a few lines for scrolling purposes", |
| "these", "are", "offscreen" |
| ) + (1..100).map { "$it" } |
| ) { |
| Text(text = it, fontSize = 80.sp) |
| |
| if (it.contains("works")) { |
| Text("You can even emit multiple components per item.") |
| } |
| } |
| } |
| |
| @Composable |
| private fun ListAddRemoveItemsDemo() { |
| var numItems by state { 0 } |
| var offset by state { 0 } |
| Column { |
| Row { |
| val buttonModifier = Modifier.padding(8.dp) |
| Button(modifier = buttonModifier, onClick = { numItems++ }) { Text("Add") } |
| Button(modifier = buttonModifier, onClick = { numItems-- }) { Text("Remove") } |
| Button(modifier = buttonModifier, onClick = { offset++ }) { Text("Offset") } |
| } |
| Column { |
| LazyColumnItems((1..numItems).map { it + offset }.toList()) { |
| Text("$it", style = currentTextStyle().copy(fontSize = 20.sp)) |
| } |
| } |
| } |
| } |
| |
| @Composable |
| fun Button(modifier: Modifier, onClick: () -> Unit, children: @Composable () -> Unit) { |
| Box( |
| modifier = modifier.clickable(onClick = onClick), |
| shape = RoundedCornerShape(4.dp), |
| backgroundColor = Color(0xFF6200EE), |
| paddingStart = 16.dp, |
| paddingEnd = 16.dp, |
| paddingTop = 8.dp, |
| paddingBottom = 8.dp |
| ) { |
| Providers(ContentColorAmbient provides Color.White) { |
| children() |
| } |
| } |
| } |
| |
| @Composable |
| private fun LazyRowItemsDemo() { |
| LazyRowItems(items = (1..1000).toList()) { |
| Square(it) |
| } |
| } |
| |
| @Composable |
| private fun Square(index: Int) { |
| val width = remember { Random.nextInt(50, 150).dp } |
| Box( |
| Modifier.preferredWidth(width).fillMaxHeight(), |
| backgroundColor = colors[index % colors.size], |
| gravity = ContentGravity.Center |
| ) { |
| Text(index.toString()) |
| } |
| } |
| |
| private val colors = listOf( |
| Color(0xFFffd7d7.toInt()), |
| Color(0xFFffe9d6.toInt()), |
| Color(0xFFfffbd0.toInt()), |
| Color(0xFFe3ffd9.toInt()), |
| Color(0xFFd0fff8.toInt()) |
| ) |