LazyColumnFor does not scroll smoothly as ScrollableColumn [168293643]

Fixed

Bug

Status Update

No update yet.

Description

gs...@gmail.com

created issue #1

Sep 12, 2020 01:39PM

Android Studio Build: Android Studio Canary 9
Version of Gradle Plugin: gradle:4.2.0-alpha09
OS: Android 9

Compose version : 1.0.0-alpha02
Kotlin compiler: 1.4.0

Problem

When I use LazyColumnFor and try to drag all the list to the end or do a fast drag between items it seems like its choppy and not smooth, if I drag till the end it will glitch on the last item

Example

@Composable
fun RecipeColumnListDemo(recipeList:List<Recipe>){
LazyColumnFor(items = recipeList) { item ->
RecipeCard(recipe = item)
}
}

where RecipeCard(recipe) loads images sincronously

@Composable
private fun RecipeCard(recipe: Recipe){
val image = imageResource(R.drawable.header)
Surface(shape = RoundedCornerShape(8.dp),elevation = 8.dp,modifier = Modifier.padding(8.dp)) {
Column(modifier = Modifier.padding(16.dp)) {
val imageModifier = Modifier.preferredHeight(150.dp).fillMaxWidth().clip(shape = RoundedCornerShape(8.dp))
Image(asset = image,modifier = imageModifier,contentScale = ContentScale.Crop)
Spacer(modifier = Modifier.preferredHeight(16.dp))
Text(text = recipe.title,style = typography.h6)
for(ingredient in recipe.ingredients){
Text(text = "* $ingredient",style = typography.body2)
}
}
}
}

I have also changed the way I load images with loadImageResource, but its also not a smooth scroll when I fast drag to the end of the list

Is this issue on my side ?

I have tried JetChat and it uses a ScrollableColumn which the scrolling is smoother than the the LazyColumnFor

Video:

https://drive.google.com/file/d/1RniEokUmaVlehvMBRNjMPZS9AgIXkVZI/view?usp=sharing

Comments

gs...@gmail.com <gs...@gmail.com> #2Sep 12, 2020 03:59PM

Code in question

val textAlign: TextAlign get() = this.paragraphStyle.textAlign

@Deprecated("Kept for backwards compatibility.", level = DeprecationLevel.WARNING)
@get:JvmName("getTextAlign")
@Suppress("unused")
val deprecated_boxing_textAlign: TextAlign? get() = this.textAlign

and the bytecode that studio shows me:

  // access flags 0x11
  public final getTextAlign-e0LSkKk()I
   L0
    LINENUMBER 1405 L0
    ALOAD 0
    GETFIELD androidx/compose/ui/text/TextStyle.paragraphStyle : Landroidx/compose/ui/text/ParagraphStyle;
    INVOKEVIRTUAL androidx/compose/ui/text/ParagraphStyle.getTextAlign-e0LSkKk ()I
    IRETURN
   L1
    LOCALVARIABLE this Landroidx/compose/ui/text/TextStyle; L0 L1 0
    MAXSTACK = 1
    MAXLOCALS = 1

  // DEPRECATED
  // access flags 0x20011
  public final getTextAlign()Landroidx/compose/ui/text/style/TextAlign;
  @Lkotlin/jvm/JvmName;(name="getTextAlign") // invisible
  @Lorg/jetbrains/annotations/Nullable;() // invisible
   L0
    LINENUMBER 1410 L0
    ALOAD 0
    INVOKEVIRTUAL androidx/compose/ui/text/TextStyle.getTextAlign-e0LSkKk ()I
    INVOKESTATIC androidx/compose/ui/text/style/TextAlign.box-impl (I)Landroidx/compose/ui/text/style/TextAlign;
    ARETURN
   L1
    LOCALVARIABLE this Landroidx/compose/ui/text/TextStyle; L0 L1 0
    MAXSTACK = 1
    MAXLOCALS = 1

cl...@google.com <cl...@google.com> Sep 14, 2020 09:25AM

Assigned to an...@google.com.

an...@google.com <an...@google.com> #3Sep 14, 2020 01:19PM

Inspected the JARs

❯ javap -cp 1.6.0-rc01-classes.jar androidx.compose.ui.text.TextStyle | grep getTextAlign
  public final int getTextAlign-e0LSkKk();
  public final androidx.compose.ui.text.style.TextAlign getTextAlign();
  public static void getTextAlign$annotations();

❯ javap -cp 1.5.4-classes.jar androidx.compose.ui.text.TextStyle | grep getTextAlign
  public final androidx.compose.ui.text.style.TextAlign getTextAlign-buA522U();

gs...@gmail.com <gs...@gmail.com> #4Sep 14, 2020 01:30PM

More info on the hash appended to the jvm signature names. At a high level, the hash is changing because it returns a nullable type in 1.5.4, but a non-null type in 1.6.0-rc01. The rest of the contents of the hash are the same.

ap...@google.com <ap...@google.com> #5Sep 23, 2020 11:17AM

Possible fix looks like it would be to include the hash in JvmName annotation.

@get:JvmName("getTextAlign-buA522U")

ap...@google.com <ap...@google.com> #6Oct 6, 2020 12:21PM

In addition to TextAlign, we've changed TextDirection, Hyphens and LineBreak at the same time. So let's update all of them at once.

an...@google.com <an...@google.com> #7Oct 7, 2020 02:06PM

Marked as fixed.

Created go/mangling-binary-compat explaining the problem in further detail.

al...@mercari.com <al...@mercari.com> #8Oct 20, 2020 01:12PM

minimal repro attached

Message last modified on Oct 20, 2020 01:14PM

an...@google.com <an...@google.com> #9Oct 20, 2020 01:21PM

Verified the fix in aosp/2918751.

In Android Studio I built aosp/2918751 by running the demo app.

Then, I found the jar file used in the build at:

~/workspace/androidx-main/out/androidx/compose/ui/ui-text/build/intermediates/compile_library_classes_jar/debug/bundleLibCompileToJarDebug/classes.jar

I modified the repro project build.gradle (project, not library) to remove the module being changed via adding the following above dependencies at the top level:

configurations.all {
    exclude(group = "androidx.compose.ui", module = "ui-text")
}

and then adding it back in to the project via the following inside the dependencies:

dependencies {
    ...
    implementation(files("~/workspace/androidx-main/out/androidx/compose/ui/ui-text/build/intermediates/compile_library_classes_jar/debug/bundleLibCompileToJarDebug/classes.jar"))
}

By this not immediately crashing on start up, it verifies that the currently incompatible methods have been made compatible with the change in aosp/2918751.