Useful binding adapters

UsefulBindingAdapters.kt

object GeneralBindingAdapters {
    /**
     * To allow binding image resource Int in addition to Drawable.
     * Saves you from depending on Resouces in the ViewModel,
     */
    @JvmStatic
    @BindingAdapter("android:src")
    fun setImageResource(imageView: ImageView, resource: Int) {
        imageView.setImageResource(resource)
    }

    /** Set visibility on a View to VISIBLE or GONE depending on Boolean value */
    @JvmStatic
    @BindingAdapter("visibleOrGone")
    fun setViewVisibleOrGoneFromBoolean(view: View, show: Boolean) {
         view.visibility = if (show) View.VISIBLE else View.GONE
    }

    /** Set visibility on a View to VISIBLE or INVISIBLE depending on Boolean value */
    @JvmStatic
    @BindingAdapter("visibleOrInvisible")
    fun setViewVisibleOrInvislbleFromBoolean(view: View, show: Boolean) {
        view.visibility = if (show) View.VISIBLE else View.INVISIBLE
    }

    /** Hides the view by setting Visibility.GONE if the object referenced is NULL */
    @JvmStatic
    @BindingAdapter("goneIfNull")
    fun setViewVisibleOrGoneFromObject(view: View, obj: Any?) {
        view.visibility = if (obj != null) View.VISIBLE else View.GONE
    }

    /** 
      * Bind to function without input parameters for a click listener.
      * Stops you from getting those pesky "unused variable" warnings all over
      * the place when "view: View" is unused.
      */
    @JvmStatic
    @BindingAdapter("onClick")
    fun onClick(view: View, action: (() -> Unit)?) {
        view.setOnClickListener {
            action?.invoke()
        }
    }
    
    /**
     * Binding to "android:string" will crash if the int value is 0. This will not.
     */
    @JvmStatic
    @BindingAdapter("android:text")
    fun setStringFromRes(textView: TextView, @StringRes res: Int) {
        val textToSet = if (res == 0) "" else textView.resources.getString(res)
        if (textView.text != textToSet) textView.text = textToSet
    }
}