hey guys, I cloned official jetpack compose sample from github. it lacks back press functional and I want to add it by myself. is there any recommended ways that can I use?

Have anyone a suggestion on how to mimick the XML ImageView's android:scaleType="fitCenter" in JetPack Compose ? Have tried to wrap a DrawImage in a Container with a dedicated size (i.e 40.dpx40.dp), for all my square images, this seems ok, but on images which is either higher or wider, the image doesn't resize so it fits into the square, it gets cut off either in height or in width. It should also keep its aspect ratio if it resizes.

Container(
                                width = 40.dp,
                                height = 40.dp
                            ) {
                                DrawImage(image)
                            }

RG

Dumb question: how to close the keyboard when the user press the imeAction button in a

TextField

?

TextField(
    value = text.value,
    keyboardType = KeyboardType.Text,
    imeAction = ImeAction.Done,
    onImeActionPerformed = {
        // TODO how to close the keyboard?
    },
    onValueChange = { s -> text.value = s }
)

This message was deleted.

According to material.io buttons should show text in ALLCAPS to emphasize (especially textbuttons), but when testing the JetPack Compose Button styles i cannot see that particular style has been applied to Button. Or do I have to capitalize the text myself (Not quite right after the material.io guidelines though...) Any suggestions ?

I am missing the ability to add an image to the ContainedButtonStyle button, which is/was possible in the XML's <Button style="@style/Widget.MaterialComponents.Button.Icon" app:icon="@drawable/my_edit_pen"/>, or do I need to design my own material IconContainedButton (I'd rather not).

Is there a better way to do this?

Text(
    text = "H4 Primary!",
    style = +themeTextStyle {
        h4.copy(
            color = +themeColor { 
                primary 
            }
        )
    }
)

Have anyone successfully combined Room and Compose. I am getting this compiler error when I turn on "`buildFeatures { compose true }`" and have kapt annotationProcessor on (

kapt 'androidx.room:room-compiler:2.2.2'

):

e: java.lang.NoSuchMethodError: org.jetbrains.kotlin.codegen.state.GenerationState$Builder.isIrBackend(Z)Lorg/jetbrains/kotlin/codegen/state/GenerationState$Builder;
	at org.jetbrains.kotlin.kapt3.AbstractKapt3Extension.contextForStubGeneration(Kapt3Extension.kt:267)
	at org.jetbrains.kotlin.kapt3.AbstractKapt3Extension.analysisCompleted(Kapt3Extension.kt:164)
	at org.jetbrains.kotlin.kapt3.ClasspathBasedKapt3Extension.analysisCompleted(Kapt3Extension.kt:98)
	at org.jetbrains.kotlin.cli.jvm.compiler.TopDownAnalyzerFacadeForJVM$analyzeFilesWithJavaIntegration$2.invoke(TopDownAnalyzerFacadeForJVM.kt:97)
	at org.jetbrains.kotlin.cli.jvm.compiler.TopDownAnalyzerFacadeForJVM.analyzeFilesWithJavaIntegration(TopDownAnalyzerFacadeForJVM.kt:107)
	at org.jetbrains.kotlin.cli.jvm.compiler.TopDownAnalyzerFacadeForJVM.analyzeFilesWithJavaIntegration$default(TopDownAnalyzerFacadeForJVM.kt:82)
	at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler$analyze$1.invoke(KotlinToJVMBytecodeCompiler.kt:558)
	at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler$analyze$1.invoke(KotlinToJVMBytecodeCompiler.kt:85)
	at org.jetbrains.kotlin.cli.common.messages.AnalyzerWithCompilerReport.analyzeAndReport(AnalyzerWithCompilerReport.kt:107)
	at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler.analyze(KotlinToJVMBytecodeCompiler.kt:549)
	at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler.compileModules$cli(KotlinToJVMBytecodeCompiler.kt:180)
	at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler.doExecute(K2JVMCompiler.kt:172)
	at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler.doExecute(K2JVMCompiler.kt:56)
	at org.jetbrains.kotlin.cli.common.CLICompiler.execImpl(CLICompiler.kt:85)
	at org.jetbrains.kotlin.cli.common.CLICompiler.execImpl(CLICompiler.kt:43)
	at org.jetbrains.kotlin.cli.common.CLITool.exec(CLITool.kt:104)
	at org.jetbrains.kotlin.incremental.IncrementalJvmCompilerRunner.runCompiler(IncrementalJvmCompilerRunner.kt:349)
	at org.jetbrains.kotlin.incremental.IncrementalJvmCompilerRunner.runCompiler(IncrementalJvmCompilerRunner.kt:105)
	at org.jetbrains.kotlin.incremental.IncrementalCompilerRunner.compileIncrementally(IncrementalCompilerRunner.kt:237)
	at org.jetbrains.kotlin.incremental.IncrementalCompilerRunner.access$compileIncrementally(IncrementalCompilerRunner.kt:37)
	at org.jetbrains.kotlin.incremental.IncrementalCompilerRunner$compile$2.invoke(IncrementalCompilerRunner.kt:79)
	at org.jetbrains.kotlin.incremental.IncrementalCompilerRunner.compile(IncrementalCompilerRunner.kt:91)
	at org.jetbrains.kotlin.daemon.CompileServiceImplBase.execIncrementalCompiler(CompileServiceImpl.kt:606)
	at org.jetbrains.kotlin.daemon.CompileServiceImplBase.access$execIncrementalCompiler(CompileServiceImpl.kt:99)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl.compile(CompileServiceImpl.kt:1645)
	at sun.reflect.GeneratedMethodAccessor101.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:357)
	at sun.rmi.transport.Transport$1.run(Transport.java:200)
	at sun.rmi.transport.Transport$1.run(Transport.java:197)
	at java.security.AccessController.doPrivileged(Native Method)
	at sun.rmi.transport.Transport.serviceCall(Transport.java:196)
	at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:573)
	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:834)
	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$0(TCPTransport.java:688)
	at java.security.AccessController.doPrivileged(Native Method)
	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:687)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':app:kaptGenerateStubsDebugKotlin'.
> Internal compiler error. See log for more details
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
* Get more help at <https://help.gradle.org>
BUILD FAILED in 2s

Here's the issuetracker node for this one: https://issuetracker.google.com/145557605 RG

How will navigation work in Jetpack compose (since Navigation Components currently seems to be based on Fragments)?

I’m playing with custom components in Compose… Is there a way to capture the on touch (and get the X/Y position)? 🤔

is it just me that The Jetpack Compose IDE plugin is Incompatible of Android Studio 4.0 Canary 5?

Checking out

dev03

changes and I am little bit wondered why the quite good structuring in

dev02

has been "abandoned" with "parameters" (here: modifiers):

//dev02
@Composable
private fun BottomBarAction(
    @DrawableRes id: Int,
    onClick: () -> Unit
) {
    Ripple(
        bounded = false,
        radius = 24.dp
    ) {
        Clickable(onClick = onClick) {
            Padding(12.dp) {
                Container(width = 24.dp, height = 24.dp) {
                    DrawVector(+vectorResource(id))
                }
            }
        }
    }
}

//dev03
@Composable

private fun BottomBarAction(
    @DrawableRes id: Int,
    onClick: () -> Unit
){
    Ripple(
        bounded = false,
        radius = 24.dp
    ){
        Clickable(onClick = onClick) {
            Container(modifier = Spacing(12.dp) wraps Size(24.dp, 24.dp)) {
                DrawVector(vectorImage = +vectorResource(id))
            }
        }
    }
}

Before I felt i had control over the layout structure, but now

Padding

has become a

Spacing

modifier

whics

wraps

a

Size

.. ? I somehow lost the control here. Or is there fear that the structuring will become too deep in complex layouts, and therefore it is parameterized, or is the situation simply that there are several parallel layers of structuring -> causing the parameterization. RG

I suddenly got Classless programming with Kotlin+Compose... ...thats really spooky 👻

Compose, multiple parameters which could be lambdas: My suggestion is to have a

@Lambda

annotation in front of the function which should intendly be the lambda function. i.e.:

private fun BottomBar(
    post: Post, 
    @Lambda onUnimplementedAction: () -> Unit){
...
}

If it isn't already suggested before. RG

@Clara Bayarri I saw your talk at KotlinConf on Compose, and specifically about the Single Child Composable Problem you mentioned. Is it not possible for something like a Button to query the number of children in the lamba and throw a warning if its more than 1? That’d force me as a developer to then include a Row or Column to wrap multiple children, the Row/Column children lambdas would be unbounded in the number they could include.

Where can I find the API changes from dev02 to dev03? I have a presentation tomorrow and I’d like to update the content…

I got this one today, when "converting" from dev02 to dev03:

Overload resolution ambiguity. All these functions match.
public fun Size(width: Dp, height: Dp): LayoutModifier defined in androidx.ui.layout
public inline fun Size(width: Dp, height: Dp): Size defined in androidx.ui.core

is this actually the same function ?

If the preview window breaks (doesn't display anything), what do we file tickets against? Using AS 4.0 Canary 5 w/ the 4.0.0-alpha05 AGP plugin. Not sure if this is an AGP problem or AS problem. Rebuild of app didn't help... nvm: found it: <https😕/issuetracker.google.com/issues?q=componentid:612128>

VerticalScroller onScrollPositionChanged which was available in dev02 has disappeared in dev03. Do any have any clues how to read the VerticalScrollers postion now, or do we use another method to register scrollingchanges ?

Where does Compose get Button theme styling from? I created a new project and then changed the colorPrimary, etc. colors in my colors.xml so the non-Compose parts of the app changed colors, but the Compose part didn't. This was a unexpected :-)

When will it be possible to combine @Composable and Room ? I think its crucial that those two features can coexist. RG

I wanted to checkout how to draw to the canvas, but i wasnt sure where to keep my instances of Paint, which i want to reuse and not recreate on each onDraw(). I saw in the framework code this memo() function, which seems to serve this purpose. Unfortunately i didnt get it. Someone already understood how its working ?

```with(+memo { DrawShapeCacheHolder() }) {
    lastShape = shape
    Draw { canvas, parentSize ->
...
}

Is it too early to start talking about a compose style guide? Or should I check back in 6 months? :troll:

Simple, but still problematic. Before we had

crossAxisAlignment

(and

mainAxisAlignment

) which we could sett to

CrossAxisAlignement.End

( or

MainAxisAlignment.End

) I want to align thos two texts below to the right, how is that done in dev03 ?

Column(modifier = Spacing(right = 4.dp) )
{
    Surface(color = Color.Blue) {
        Text(text = "2019.12.09 12:00")
    }
    Surface(color = Color.Red) {
        
        Text(text = "14d 16h 00min")
    }
}

I am having issues running Flows along side Jetpack Compose. If I "collectEach", the compiler will throw an IR exception. I know there was an incompatibility between coroutines and compose at one point in the past, but is this still the case?

hi - i'm trying to use LiveData and Compose with a pretty simple use case. However, I am getting the following stack trace, as soon as my @Composable calls a method that takes a parameter... It's a bit confusing. I don't know what's going on under the hood, so can't really add much more detail... This works

Column {
                        devices.map {
                            Text(text = it.name)
                        }
                    }

This fails:

Column {
                        devices.map(::device)
                    }
[...]
@Composable
private fun device(device: UpnpDevice) {
    Text(text = device.name)
}

the stacktrace is:

2-10 11:39:52.827 3603-3603/? D/Error: ERR: stack=java.lang.IllegalStateException: Expected a group start
        at androidx.compose.SlotTableKt.getAsGroupStart(SlotTable.kt:641)
        at androidx.compose.SlotTableKt.access$getAsGroupStart$p(SlotTable.kt:1)
        at androidx.compose.SlotEditor.recordStartGroup$compose_runtime_release(SlotTable.kt:150)
        at androidx.compose.SlotReader.startGroup(SlotTable.kt:277)
        at androidx.compose.SlotReader.startGroup(SlotTable.kt:273)
        at androidx.compose.ComposerKt.start(Composer.kt:1791)
        at androidx.compose.ComposerKt.access$start(Composer.kt:1)
        at androidx.compose.Composer.start(Composer.kt:776)
        at androidx.compose.Composer.startGroup(Composer.kt:397)
        at androidx.compose.ObserveKt.Observe(Observe.kt:37)
        at com.example.filecopier.FileCopierAppKt.device(FileCopierApp.kt)
        at com.example.filecopier.FileCopierAppKt.access$device$0(FileCopierApp.kt)
        at com.example.filecopier.FileCopierAppKt$fileCopierApp$1$2$invoke$1$2$invoke$1$1$invoke$1.invoke(FileCopierApp.kt:32)
        at com.example.filecopier.FileCopierAppKt$fileCopierApp$1$2$invoke$1$2$invoke$1$1$invoke$1.invoke(FileCopierApp.kt)
        at androidx.compose.ObserveKt.Observe(Observe.kt:39)
        at com.example.filecopier.FileCopierAppKt$fileCopierApp$1$2$invoke$1$2$invoke$1$1.invoke(FileCopierApp.kt)
        at com.example.filecopier.FileCopierAppKt$fileCopierApp$1$2$invoke$1$2$invoke$1$1.invoke(FileCopierApp.kt)
        at androidx.ui.layout.FlexKt$Column$1$1$invoke$1.invoke(Flex.kt:362)
        at androidx.ui.layout.FlexKt$Column$1$1$invoke$1.invoke(Flex.kt)
        at androidx.compose.ObserveKt.Observe(Observe.kt:39)
        at androidx.ui.layout.FlexKt$Column$1$1.invoke(Flex.kt)
        at androidx.ui.layout.FlexKt$Column$1$1.invoke(Flex.kt)

I'm using the

+observe

snippet previously posted... any ideas much appreciated! I should mention that the code works fine in the preview, so I'm guessing its something to do with the

observe

Has anybody else seen problems with missing and broken colors when you use Theme Colors like secondary or error on devices with API level 28 or lower? Here is an example:

MaterialTheme() {
  Card(color = +themeColor { secondary }) {
    Text("Test")
  }
}

On API 29 it looks like it should (First attached image 'API_29.png') On API 28 the colors don't get applied and thus the foregound text color is broken too. (Second image 'API_28.png') A little note to the images: Look at the top "tab" bar. The white cards with black text are OK, the ones where the green background is missing are broken.

I don’t know whats wrong with my project, but since I changed from dev2 to dev3, my

setContent

en

Text

functions wont work/import. I tried to import gradle as using api/implementation, am I missing something? Dependencies:

implementation 'androidx.ui:ui-layout:0.1.0-dev03'
implementation 'androidx.ui:ui-material:0.1.0-dev03'
implementation 'androidx.ui:ui-tooling:0.1.0-dev03'

Any release date for dev04 ?