IllegalArgumentException while using DataBinding on ImageView using LiveData

Question

I am trying to use DataBinding to add an Image to an ImageView.

I am fetching an object from a Room database and exposing the title and image URL as LiveData. I am able to set the title but the setting the image is failing.

Here's the error log

 Caused by: java.lang.IllegalArgumentException: Parameter specified as non-null is null: method kotlin.jvm.internal.Intrinsics.checkParameterIsNotNull, parameter imageUrl
    at com.sample.databinding.detail.ArticleDetailsViewModel$Companion.loadImage(Unknown Source:7)
    at com.sample.databinding.detail.ArticleDetailsViewModel.loadImage(Unknown Source:2)
    at com.sample.databinding.detail.databinding.ActivityArticleDetailsBindingImpl.executeBindings(ActivityArticleDetailsBindingImpl.java:198)
    at androidx.databinding.ViewDataBinding.executeBindingsInternal(ViewDataBinding.java:448)
    at androidx.databinding.ViewDataBinding.executePendingBindings(ViewDataBinding.java:420)
    at androidx.databinding.ViewDataBinding$OnStartListener.onStart(ViewDataBinding.java:1633)
    at java.lang.reflect.Method.invoke(Native Method)
    at androidx.lifecycle.ClassesInfoCache$MethodReference.invokeCallback(ClassesInfoCache.java:215)

Here's the line in the generated file that is failing

if ((dirtyFlags & 0x19L) != 0) {
        // api target 1

        com.sample.databinding.detail.ArticleDetailsViewModel.loadImage(this.backdrop, articleDetailsViewModelImageUrlGetValue);
    }

Here's my code

activity_details.xml

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools">

    <data>

        <variable
            name="articleDetailsViewModel"
            type="com.monzo.androidtest.detail.ArticleDetailsViewModel" />
    </data>

<androidx.coordinatorlayout.widget.CoordinatorLayout
    android:id="@+id/main_content"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true">

    <com.google.android.material.appbar.AppBarLayout
        android:id="@+id/appbar"
        android:layout_width="match_parent"
        android:layout_height="256dp"
        android:fitsSystemWindows="true"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
        app:contentScrim="?attr/colorPrimary"
        app:layout_scrollFlags="scroll|exitUntilCollapsed">

        <com.google.android.material.appbar.CollapsingToolbarLayout
            android:id="@+id/collapsingToolbar"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:fitsSystemWindows="true"
            app:contentScrim="?attr/colorPrimary"
            app:expandedTitleMarginEnd="64dp"
            app:expandedTitleMarginStart="48dp"
            app:layout_scrollFlags="scroll|exitUntilCollapsed">

            <ImageView
                android:id="@+id/backdrop"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:fitsSystemWindows="true"
                android:scaleType="centerCrop"
                app:layout_collapseMode="parallax"
                app:imageSource="@{articleDetailsViewModel.imageUrl}"/>

            <androidx.appcompat.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                app:layout_collapseMode="pin"
                app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
                app:title="@{articleDetailsViewModel.articleTitle}"/>


        </com.google.android.material.appbar.CollapsingToolbarLayout>

    </com.google.android.material.appbar.AppBarLayout>

</androidx.coordinatorlayout.widget.CoordinatorLayout>
</layout>

ActivityDetailsViewModel.kt

package com.sample.databinding.detail

import android.app.Application
import android.widget.ImageView
import androidx.core.text.HtmlCompat
import androidx.databinding.BindingAdapter
import androidx.lifecycle.LiveData
import androidx.lifecycle.MutableLiveData
import androidx.lifecycle.Transformations
import androidx.lifecycle.ViewModel
import com.bumptech.glide.Glide
import com.sample.databinding.articles.model.Article
import com.sample.databinding.data.ArticlesDao
import kotlinx.coroutines.*


class ArticleDetailsViewModel(
        val database: ArticlesDao,
        val application: Application,
        val articleID: String) : ViewModel() {

    val article = database.getSpecificPost(articleID)

    val imageUrl = Transformations.map(article) {article.value?.thumbnail}
    val  articleTitle = Transformations.map(article) {article.value?.title}




    companion object {
        @JvmStatic
        @BindingAdapter("bind:imageSource")
        fun loadImage(view: ImageView, imageUrl: String) {
            if (!imageUrl.isEmpty()) {
                Glide.with(view.getContext())
                        .load(imageUrl)
                        .into(view)

            }

        }
    }
}

Answer 1

See you have written a good code, but there is a problem in a Binding Adapter

   @JvmStatic
        @BindingAdapter("bind:imageSource")
        fun loadImage(view: ImageView, imageUrl: String) {
            if (!imageUrl.isEmpty()) {
                Glide.with(view.getContext())
                        .load(imageUrl)
                        .into(view)
            }
        }

In this code you are expecting a not null imageUrl, but during run time, this value is null. So this is throwing an exception.

To solve this, you have to mention parameter imageUrl nullable. And then you have to check whether imageUrl is null or empty. So your binding adapter method will be like this :

 @JvmStatic
        @BindingAdapter("bind:imageSource")
        fun loadImage(view: ImageView, imageUrl: String?) {
            if (!imageUrl.isNullOrBlank()) {
                Glide.with(view.getContext())
                        .load(imageUrl)
                        .into(view)
            }
        }

Hope this helps. Happy Coding :)