| /* |
| * Copyright 2022 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.lazy.layout |
| |
| import androidx.compose.runtime.Composable |
| import androidx.compose.runtime.mutableStateOf |
| import androidx.compose.ui.Modifier |
| import androidx.compose.ui.composed |
| import androidx.compose.ui.layout.AlignmentLine |
| import androidx.compose.ui.test.junit4.createComposeRule |
| import androidx.test.ext.junit.runners.AndroidJUnit4 |
| import androidx.test.filters.LargeTest |
| import com.google.common.truth.Truth.assertThat |
| import org.junit.Rule |
| import org.junit.Test |
| import org.junit.runner.RunWith |
| |
| @LargeTest |
| @RunWith(AndroidJUnit4::class) |
| class LazyLayoutTest { |
| |
| @get:Rule |
| val rule = createComposeRule() |
| |
| @Test |
| fun lazyListShowsCombinedItems() { |
| val counter = mutableStateOf(0) |
| var remeasureCount = 0 |
| val policy = LazyMeasurePolicy { _, _ -> |
| remeasureCount++ |
| object : LazyLayoutMeasureResult { |
| override val visibleItemsInfo: List<LazyLayoutItemInfo> = emptyList() |
| override val alignmentLines: Map<AlignmentLine, Int> = emptyMap() |
| override val height: Int = 10 |
| override val width: Int = 10 |
| override fun placeChildren() {} |
| } |
| } |
| val itemsProvider = { |
| object : LazyLayoutItemsProvider { |
| override fun getContent(index: Int): @Composable () -> Unit = {} |
| override val itemsCount: Int = 0 |
| override fun getKey(index: Int) = Unit |
| override val keyToIndexMap: Map<Any, Int> = emptyMap() |
| override fun getContentType(index: Int): Any? = null |
| } |
| } |
| |
| rule.setContent { |
| counter.value // just to trigger recomposition |
| LazyLayout( |
| itemsProvider = itemsProvider, |
| measurePolicy = policy, |
| // this will return a new object everytime causing LazyLayout recomposition |
| // without causing remeasure |
| modifier = Modifier.composed { Modifier } |
| ) |
| } |
| |
| rule.runOnIdle { |
| assertThat(remeasureCount).isEqualTo(1) |
| counter.value++ |
| } |
| |
| rule.runOnIdle { |
| assertThat(remeasureCount).isEqualTo(1) |
| } |
| } |
| } |
