BindingAdapter（kotlin自定义数据绑定）

app module的build.gradle文件添加

apply plugin: 'kotlin-kapt'

• ImageView

@BindingAdapter("imageFromUrl")
fun bindImageFromUrl(view: ImageView, imageUrl: String?) {
    if (!imageUrl.isNullOrEmpty()) {
        Glide.with(view.context)
                .load(imageUrl)
                .transition(DrawableTransitionOptions.withCrossFade())
                .into(view)
    }
}

 <ImageView
                    android:id="@+id/detail_image"
                    android:layout_width="match_parent"
                    android:layout_height="@dimen/plant_detail_app_bar_height"
                    android:contentDescription="@string/plant_detail_image_content_description"
                    android:fitsSystemWindows="true"
                    android:scaleType="centerCrop"
                    app:imageFromUrl="@{viewModel.plant.imageUrl}"
                    app:layout_collapseMode="parallax" />

• View Gone

@BindingAdapter("isGone")
fun bindIsGone(view: View, isGone: Boolean) {
    view.visibility = if (isGone) {
        View.GONE
    } else {
        View.VISIBLE
    }
}

@BindingAdapter("isGone")
fun bindIsGone(view: FloatingActionButton, isGone: Boolean?) {
    if (isGone == null || isGone) {
        view.hide()
    } else {
        view.show()
    }
}

//xml使用app:isGone="@{!hasPlantings}"
//UI赋值 binding.hasPlantings = !result.isNullOrEmpty()

• TextView

@BindingAdapter("renderHtml")
fun bindRenderHtml(view: TextView, description: String?) {
    if (description != null) {
        view.text = HtmlCompat.fromHtml(description, FROM_HTML_MODE_COMPACT)
        view.movementMethod = LinkMovementMethod.getInstance()
    } else {
        view.text = ""
    }
}

                <TextView
                    android:id="@+id/plant_description"
                    style="?android:attr/textAppearanceMedium"
                    android:layout_width="0dp"
                    android:layout_height="wrap_content"
                    android:layout_marginStart="@dimen/margin_small"
                    android:layout_marginTop="@dimen/margin_small"
                    android:layout_marginEnd="@dimen/margin_small"
                    android:textIsSelectable="true"
                    android:minHeight="@dimen/plant_description_min_height"
                    app:layout_constraintEnd_toEndOf="parent"
                    app:layout_constraintStart_toStartOf="parent"
                    app:layout_constraintTop_toBottomOf="@id/plant_watering"
                    app:renderHtml="@{viewModel.plant.description}"
                    tools:text="Details about the plant" />

   @BindingAdapter(value = ["licenseNumber","vinLast4"])
    @JvmStatic
   fun bindText(textView: TextView,licenseNumber: String,vinLast4:String){
       if (licenseNumber==""){
           textView.text = vinLast4
       }else{
           textView.text = licenseNumber
       }
   }
   
   
                       <TextView
                        android:id="@+id/tv_item_name"
                        android:layout_width="wrap_content"
                        android:layout_height="25dp"
                        android:textSize="14sp"
                        android:textColor="#ff696d77"
                        android:gravity="center_vertical"
                        app:licenseNumber="@{myData.licenseNumber}"
                        app:vinLast4="@{myData.vinLast4}"/>