Kotlin layout width and height binding

Question

I've googled and tried examples but I'm unable to perform binding a FrameLayout width and height. The other bindings work fine.

Final Solution: Example project: https://github.com/jchristof/SimpleDatabindingExample

panel.xml:

<layout>
    <data class="PanelControlBinding">
        <variable
            name="panel"
            type="com.example.viewmodels.ContainerViewModel"/>
    </data>
    <FrameLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="@{panel.width}"
        android:layout_height="@{panel.height}"
        android:translationX="@{panel.left}"
        android:translationY="@{panel.top}"
        android:background="@{panel.background}"
        >

    </FrameLayout>
</layout>

binding.kt kotlin file

@BindingAdapter("android:layout_width")
fun setLayoutWidth(view: View, width: Int) {
    val layoutParams = view.layoutParams
    layoutParams.width = width
    view.layoutParams = layoutParams
}

I've tried a number of permutations on the width type (setting it to Float) as well as removing the android: namespace, declaring the setLayoutWidth as a static companion object etc.

I continue to get the error:

Found data binding errors.
****/ data binding error ****msg:Cannot find the setter for attribute 'android:layout_width' with parameter type java.lang.Integer on android.widget.FrameLayout.
file:D:\Projects\strandXmlAppRunner\app\src\main\res\layout\panel.xml
loc:9:32 - 9:42
****\ data binding error ****

How do I need to change these declarations to enable binding on the layout width and height?

Edit

also tried adding an import to the binding adapter:

<data class="PanelControlBinding">
    <import type="com.example.services.BindingKt"/>
    <variable
        name="panel"
        type="com.example.viewmodels.ContainerViewModel"/>
</data>

same error

Edit

going back to my ContainerViewModel, I notice that if I change the return type of width from Int? to Int:

open class ContainerViewModel(val attributes: IValuesStore<String>) {
    val width:Int
        get() = placementArea?.width?.toInt() ?: 0
}

slightly different error:

Found data binding errors.
****/ data binding error ****msg:Cannot find the setter for attribute 'android:layout_width' with parameter type int on android.widget.FrameLayout.
file:D:\Projects\strandXmlAppRunner\app\src\main\res\layout\panel.xml
loc:11:32 - 11:42
****\ data binding error ****

type java.lang.Integer vs type int

Edit

per suggestion, modified to include default values:

<FrameLayout
    android:layout_width="@{panel.width, default=wrap_content}"
    android:layout_height="@{panel.height, default=wrap_content}"
    android:translationX="@{panel.left}"
    android:translationY="@{panel.top}"
    android:background="@{panel.background}"
    >

</FrameLayout>

and

@BindingAdapter("android:layout_width")
fun setLayoutWidth(view: View, width: Float) {
    val layoutParams = view.layoutParams
    layoutParams.width = width.toInt()
    view.layoutParams = layoutParams
}

makes no difference:

Found data binding errors.
****/ data binding error ****msg:Cannot find the setter for attribute 'android:layout_width' with parameter type int on android.widget.FrameLayout.
file:D:\Projects\strandXmlAppRunner\app\src\main\res\layout\panel.xml
loc:11:32 - 11:42
****\ data binding error ****

Answer 1

To make DataBinding work for layout_width and layout_height, you have to give a default width and height to the view. So what you can do is change xml to something like this:

<layout>
<data class="PanelControlBinding">
    <variable
        name="panel"
        type="com.example.viewmodels.ContainerViewModel"/>
</data>
<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="@{panel.width, default=wrap_content}"
    android:layout_height="@{panel.height, default=wrap_content}"
    android:translationX="@{panel.left}"
    android:translationY="@{panel.top}"
    android:background="@{panel.background}"
    >
</FrameLayout>

And your BindingAdapter like this:

@BindingAdapter("android:layout_width")
fun setLayoutWidth(view: View, width: float) {
val layoutParams = view.layoutParams
layoutParams.width = width
view.layoutParams = layoutParams
}

Try this once, it should work. Let me know if it doesn't work.

EDIT

To make your project work, i have added these things to the build.gradle(Module: app)

1 added apply plugin: 'kotlin-kapt' to the top level plugins.

2 added this to the android tag:

kapt {
    generateStubs = true
}

After these changes, clean and rebuild the project before running.

It will work hopefully.:)