kotlinlang #compose

com.zk.trackshows E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.zk.trackshows, PID: 22201
    java.lang.IllegalArgumentException: Layer is redrawn for LayoutNode in state NeedsRelayout [LayoutNode@56ee45a children: 1 measureBlocks: androidx.compose.ui.layout.SubcomposeLayoutState$createMeasureBlocks$1@772aaf4]
        at androidx.compose.ui.node.LayerWrapper.invoke(LayerWrapper.kt:167)
        at androidx.compose.ui.node.LayerWrapper.invoke(Unknown Source:3)
        at androidx.compose.ui.platform.RenderNodeApi29$record$1$1.invoke(RenderNodeApi29.kt:159)
        at androidx.compose.ui.platform.RenderNodeApi29$record$1$1.invoke(Unknown Source:0)
        at androidx.compose.runtime.snapshots.Snapshot$Companion.observe(Snapshot.kt:1721)
        at androidx.compose.runtime.snapshots.SnapshotStateObserver.observeReads(SnapshotStateObserver.kt:128)
        at androidx.compose.ui.platform.AndroidComposeView.observeLayerModelReads(AndroidComposeView.kt:494)
        at androidx.compose.ui.platform.RenderNodeApi29.record(RenderNodeApi29.kt:158)
        at androidx.compose.ui.platform.RenderNodeLayer.updateDisplayList(RenderNodeLayer.kt:192)
        at androidx.compose.ui.platform.AndroidComposeView.dispatchDraw(AndroidComposeView.kt:563)
        at android.view.View.draw(View.java:22175)
        at android.view.View.updateDisplayListIfDirty(View.java:21024)
        at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:4441)
        at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:4414)
        at android.view.View.updateDisplayListIfDirty(View.java:20984)
        at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:4441)
        at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:4414)
        at android.view.View.updateDisplayListIfDirty(View.java:20984)
        at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:4441)
        at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:4414)
        at android.view.View.updateDisplayListIfDirty(View.java:20984)
        at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:4441)
        at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:4414)
        at android.view.View.updateDisplayListIfDirty(View.java:20984)
        at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:4441)
        at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:4414)
        at android.view.View.updateDisplayListIfDirty(View.java:20984)
        at android.view.ThreadedRenderer.updateViewTreeDisplayList(ThreadedRenderer.java:582)
        at android.view.ThreadedRenderer.updateRootDisplayList(ThreadedRenderer.java:588)
        at android.view.ThreadedRenderer.draw(ThreadedRenderer.java:665)
        at android.view.ViewRootImpl.draw(ViewRootImpl.java:4048)
        at android.view.ViewRootImpl.performDraw(ViewRootImpl.java:3757)
        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:3026)
        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1963)
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:8237)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1239)
        at android.view.Choreographer.doCallbacks(Choreographer.java:1041)
        at android.view.Choreographer.doFrame(Choreographer.java:953)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:1220)
        at android.os.Handler.handleCallback(Handler.java:883)
        at android.os.Handler.dispatchMessage(Handler.java:100)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7711)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:516)

The crash does not happen when scrolling slowly. I am using RemoteMediator with local and remote data sources.

v79

12/12/2020, 9:00 AM

Just started having a look at Jetback compose.... decided it's not for me when I saw a variable declaration as `

val count = remember { mutableStateOf(0) }

I mean, what does that even mean? What's wrong with

var count = 0

val count: IntWrapper = IntWrapper(0)

remember

isn't listed as in import, control-clicking doesn't take me to a declaration. It's wilfully obtuse!

Nat Strangerweather

12/12/2020, 9:11 AM

Does anybody know where I can find out how to pass a variable from one Composable to another?

Shakil Karim

12/12/2020, 10:48 AM

I am facing performance issues on some devices while using Compose, Specially on scrolling, Is it a known issue?

carbaj0

12/12/2020, 2:09 PM

java.lang.NoSuchMethodError: No interface method withRestorableState(Ljava/lang/Object;Lkotlin/jvm/functions/Function2;Landroidx/compose/runtime/Composer;I)V in class Landroidx/compose/runtime/savedinstancestate/RestorableStateHolder; or its super classes (declaration of 'androidx.compose.runtime.savedinstancestate.RestorableStateHolder' appears in /data/app/com.acv.composeland-V85a_e5F918MbctysYPnqQ==/base.apk)
        at androidx.navigation.compose.NavHostKt.withRestorableState(NavHost.kt:143)
        at androidx.navigation.compose.NavHostKt.access$withRestorableState(Unknown Source:0)
        at androidx.navigation.compose.NavHostKt$NavHost$5.invoke(NavHost.kt:130)
        at androidx.navigation.compose.NavHostKt$NavHost$5.invoke(Unknown Source:10)
        at androidx.compose.runtime.internal.ComposableLambda.invoke(ComposableLambda.kt:146)
        at androidx.compose.runtime.internal.ComposableLambda.invoke(Unknown Source:10)
        at androidx.compose.runtime.AmbientKt.Providers(Ambient.kt:187)
        at androidx.navigation.compose.NavHostKt.NavHost(NavHost.kt:126)
        at androidx.navigation.compose.NavHostKt$NavHost$6.invoke(Unknown Source:8)
        at androidx.navigation.compose.NavHostKt$NavHost$6.invoke(Unknown Source:10)
        at androidx.compose.runtime.RecomposeScope.compose(Composer.kt:286)

Adriano Celentano

12/12/2020, 3:18 PM

any idea why my TextField input is jumping ?

Bildschirmvideo aufnehmen 2020-12-12 um 16.09.41.mov

Leon K

12/12/2020, 5:57 PM

Hey, I'm currently trying to implement an android on-screen keyboard, doing the UI with Jetpack compose if possible. I've gotten errors about missing ViewTreeLifecycleOwner, ViewTreeViewModelStoreOwner, and ViewTreeSavedStateRegistryOwner.... is it even possible to do this? given that the keyboard stuff seems to be handled via a View, could these even have a ViewTreeViewModelStoreOwner and stuff like that? It seems as though the Compose stuff is bound to running inside of an activity, which - as far as i can tell - doesn't translate to the Input Method API

robnik

12/12/2020, 6:56 PM

I notice the JetNews sample uses it's own navigation ViewModel, instead of NavController and NavHost as documented here https://developer.android.com/jetpack/compose/navigation. The JetNews code looks easier to understand, and I'm wondering if there is a good reason to bother with NavController. I don't think it supports multiple back stacks (one per tab), which I want.

robnik

12/13/2020, 3:31 AM

I know there is a bug where

LazyColumnFor

does not remember things when items are removed and shifted. I heard that

key(...)

provides a workaround. I tried this, but it didn't work:

LazyColumnFor(items = nums) { listNum ->
   key(listNum) {
      val r = remember { Random.nextInt(300) }
      Text("Num: $listNum, remembered: $r")
   }
}

nums

is mutable state. When I remove the first item, all the remembered numbers change.

Kshitij Patil

12/13/2020, 4:52 AM

Does this remember scroll position and

snapToIndex

APIs for LazyColumn are added in

alpha08

? I'm using

alpha07

and I do get behavior of remembering scroll position on putting app background but it's not working when I switch the tab and come back (I'm using multi backstack Navigation) so I was expecting it to work

zsperske

12/13/2020, 5:39 AM

is there a way to achieve negative padding? I'm implementing swipe to dismiss on a list and while I want my list item's content to be padded from the edge, I would like the red bar which appears as you swipe to have no padding and emerge from the edge

Spikey Sanju

12/13/2020, 7:34 AM

How to change the TextField text color in Jetpack Compose?

val username = remember { mutableStateOf(TextFieldValue()) }
TextField(
    modifier = Modifier.fillMaxWidth().padding(16.dp, 0.dp, 16.dp, 0.dp)
        .constrainAs(et_username) {
            top.linkTo(title.bottom, margin = 30.dp)
        },
    label = { Text(text = "Username") },
    leadingIcon = { Icon(Icons.Outlined.Person) },
    textStyle = typography.subtitle1,
    backgroundColor = MaterialTheme.colors.background,
    value = username.value,
    onValueChange = { username.value = it }
)

ziv kesten

12/13/2020, 9:32 AM

Having problems upgrading to compose alpah08. Project wont compile now with error:

e: java.lang.NoSuchMethodError: e: java.lang.NoSuchMethodError:

'org.jetbrains.kotlin.descriptors.DescriptorVisibility org.jetbrains.kotlin.descriptors.ClassConstructorDescriptor.getVisibility()'

compose versons: compose_version = ‘1.0.0-alpha08’ nav_compose_version =‘1.0.0-alpha02’ paging_compose_version = ‘1.0.0-alpha02’ kotlin version = ‘1.4.20’ Tried invalidating caches, restart, restart AS, restart Whole machine.

tieskedh

12/13/2020, 2:59 PM

How to align two texts of different sizes by their top?

Row {
    Text(
        "h4 text",
        style = MaterialTheme.typography.h4,
    )
    Text("my icon")
}

I saw that fontsize had a lineHeight, and a baselineshift. The thing I don't get is that the baselineshift is a multiplier. How can I compute the top with it? Or is there some other way?

robnik

12/13/2020, 3:01 PM

Is there a good way to search the docs for given name/symbol from Jetpack Compose? For example, if I go to developer.android.com and search for "Text", all I get are two hits for org.w3c.dom.Text, and some other things - none of which are the Text composable.

➕ 2

Nat Strangerweather

12/13/2020, 5:26 PM

I'm testing this part of the documentation: https://developer.android.com/jetpack/compose/state#stateless-composables The problem is that

observeAsState

comes up as Unresolved Reference. Any ideas? I tried importing

import androidx.compose.runtime.livedata.observeAsState

but

livedata

is Unresolved...

Piotr

12/14/2020, 2:29 PM

Hi, i have a question regarding rtl support, is it possible to disable item (in this case linear progress indicator) from changing? I have an issue, that when i change to from ltr to rtl, the progress indicator, also changes positions(so it displays progress from right), i would like to disable that Thanks

Kshitij Patil

12/14/2020, 9:27 PM

A Custom View implementing

onTouchEvent

to handle some gestures doesn't allow gestures when used in a Composable using

AndroidView

. It used to work with compose

alpha04

(the last time I checked this Custom View). Currently I'm using

alpha07

and it's not working anymore. I tried putting that View in a xml file and inflating that layout instead which also didn't work. When I write entire screen in xml and use this View, everything works fine.

Sam

12/14/2020, 10:05 PM

Is there any way to create a pinterest (waterfall) style layout in jetpack compose? Ideally there would be a

lazyGridFor

that could have multiple columns that don’t require even-height rows, but i’d settle for fully rendering if it’s currently possible

https://user-images.githubusercontent.com/29085/56487936-b3bc2c00-6491-11e9-8493-bb89c4f00a92.png▾

gbaldeck

12/15/2020, 1:48 AM

Hi, I'm currently learning compose and am finishing up the Layouts codelab in the official docs. I am not a fan of how modifiers work, but it may be because I don't fully understand them yet. The main issue I have is this... order matters when placing modifiers, constraints flow right and size flows left. But how are you supposed to know if a constraint was changed or not? A good example is the padding and size modifiers example in the codelab. Padding does not change constraints, but size does. So placing padding before size and visa versa will have different results. It's not immediately apparent that padding does not change the constraints though. Unless there is something I'm missing, there isn't any way of knowing. With all the different types of modifiers that will be available, I can see loads of bugs arising from this. Is there any way to tell what constraints a modifier changes without looking at the source code?

👍 1

Piotr

12/15/2020, 2:07 PM

Is there a way in compose to do some equivalent of

android:includeFontPadding="false"

I have a problem with font that, I believe, could be solved by using something like that, doing modifier.padding didnt work (border added to show whats going on):

Vincent tiensi

12/15/2020, 2:10 PM

Not sure if this is a bug or not but, when I create a scaffold, I have an event that triggers opening the drawer. However this only works once, once I fire more close events it doesn’t close the drawer.

val state = viewModel.state.observeAsState().value ?: return
val scaffoldState = rememberScaffoldState()
when (state.drawerEvent?.consume()) {
    DrawerState.OPEN -> {
        scaffoldState.drawerState.open()
    }
    DrawerState.CLOSE -> {
        scaffoldState.drawerState.close()
    }
}
Scaffold(scaffoldState = scaffoldState)

robnik

12/15/2020, 6:56 PM

Documentation question... it took me too long to discover the extension function

Bitmap.asImageBitmap(): ImageBitmap

that I needed. It's not listed in either class's reference page. How is one supposed to find a function like that?

Nat Strangerweather

12/15/2020, 9:14 PM

Hi, I'm wondering if anyone would be willing to look at my code (a couple of composables) on Pastebin. The problem is that I am trying to pass my accentColor.value down from my first to my second Composable, and for some reason, this is only working for the last of my four accentColor values. I'm still learning and would be grateful for the help... 😊

laith

12/15/2020, 9:22 PM

Is Jactpack compose going to be widget rich same as flutter ?

Vinay Gaba

12/15/2020, 10:07 PM

Nice comparison between Compose and Classic Android on certain parameters by @cb - https://twitter.com/AndroidDev/status/1338967071737196544

🎉 19

robnik

12/15/2020, 10:37 PM

How do you observe a mutable object that fires events when it changes? Code that doesn't work...

@Composable fun Things(model: MyViewModel) {
    val mutableThing = model.thing
    mutableThing.addChangeListener { recomposeThisStuff() }  
    Text("${mutableThing.size} ...")

So "model.thing" may always be the same reference/object. But it changes internally.

Dominaezzz

12/16/2020, 12:09 AM

There's a typo in the doc for

InlineTextContent.children

Luis Daivid

12/16/2020, 8:41 AM

When I have a Box component, I want to show the width from x=0px to x=100px transparently. How can I do it?

allan.conda

12/16/2020, 8:48 AM

maybe Modifier.drawBehind?

Title

allan.conda

12/16/2020, 8:48 AM

maybe Modifier.drawBehind?

Luis Daivid

12/16/2020, 9:09 AM

Could it be implemented using clips?

drawBehind is so difficult..

allan.conda

12/16/2020, 9:11 AM

you wanted custom background behavior. I think it’s the only option

Luis Daivid

12/16/2020, 9:13 AM

I don’t want a custom background. I just want to crop part of the view.

robnik

12/16/2020, 11:51 AM

Crop or transparency? Those sound different to me. I just did something with cropping using

Modifier.clip(myShape)

where

myShape

is a

GenericShape { ... }

. In my preview I have a Slider that changes the width of the clip shape from 0 to 100%.

Luis Daivid

12/16/2020, 11:55 AM

@robnik Can i see code of myShape??

I think that is What i want!

robnik

12/16/2020, 12:04 PM

val myClip = GenericShape { size ->
    val right = size.width * fraction
    lineTo(right, 0f)
    lineTo(right, size.height)
    lineTo(0f, size.height)
    close()
}

And fraction is a float from state, getting moved by a slider.

Luis Daivid

12/16/2020, 12:04 PM

Thank you 😃

👍 1

Nader Jawad

12/16/2020, 6:33 PM

Just FYI,

GenericShape

will work here as a parameter to the clip modifier, however, because this is a rectangle, using

RectangleShape

to provide the clipping bounds will be more efficient as it would avoid software rasterization of paths

robnik

12/16/2020, 8:58 PM

@Nader Jawad The

RectangleShape

I see is a

val

. How do I use it? How do I give it a narrower width so that it actually clips the thing I'm trying to clip/crop?

Nader Jawad

12/16/2020, 8:58 PM

Just pass in that instance of

RectangleShape

Or you can create your own instance of Shape that creates a rectangle based on the percentage offset you wish to clip by

robnik

12/16/2020, 9:03 PM

Okay, I see - override

Shape

and return an

Outline

that is a

Rectangle

instead of a

Generic

, and get that performance benefit. Thanks!

Luis Daivid

12/17/2020, 12:48 PM

https://github.com/wooooooak/DragToPeekSurface-Compose I did it thanks to you guys. Thank you.

👍 1

allan.conda

12/17/2020, 2:16 PM

cool

View count: 4