Confusing bug with @BindingAdapter requireAll=true

[hanafey]

The example defines the binding adapter:

@BindingAdapter(value = ["app:progressScaled", "android:max"], requireAll = true)
fun setProgress(progressBar: ProgressBar, likes: Int, max: Int) {
    progressBar.progress = (likes * max / 5).coerceAtMost(max)
}

If you try to use it like so:

        <ProgressBar
            android:id="@+id/progressBar"
            tools:progressBackgroundTint="@android:color/darker_gray"
            style="?android:attr/progressBarStyleHorizontal"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            app:layout_constraintTop_toBottomOf="@+id/like_button"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintStart_toStartOf="@+id/like_button"
            app:layout_constraintEnd_toEndOf="@+id/like_button"
            android:layout_marginStart="8dp"
            android:layout_marginTop="8dp"
            android:layout_marginEnd="8dp"
            app:layout_constraintHorizontal_bias="0.5"
            app:hideIfZero="@{viewmodel.likes}"
            app:progressScaled="@{viewmodel.likes}"
            app:progressTint="@{viewmodel.popularity}"
            />

you get the following from a clean build:

.../android-databinding/app/build/generated/source/kapt/debug/com/example/android/databinding/basicsample/DataBinderMapperImpl.java:9: error: cannot find symbol
import com.example.android.databinding.basicsample.databinding.PlainActivityBindingImpl;
                                                              ^
  symbol:   class PlainActivityBindingImpl
  location: package com.example.android.databinding.basicsample.databinding

Quick, what it the problem? The required attribute android:max is not present! In contrast if you include android:max by leave off app:progressScaled the build succeeds and the binding is simply not applied.

I only changed the project by updated dependencies (including gradle) to current versions.

[timhuang1018]

Add attribute android:max="@{100}" to Progressbar tag, Data Binding won't be able to find the correct Binding Adapter if you don't use @{} to the value