The open event attendee is an android app which allows users to discover events happening around the world using the Open Event Platform. It consumes the APIs of the open event server to get a list of available events and can get detailed information about them.

Shimmer effect was created by Facebook to indicate a loading status, so instead of using ProgressBar or the usual loader use Shimmer for a better design and user interface. They also open-sourced a library called Shimmer both for Android and iOS so that every developer could use it for free.

• Add Shimmer library
• Create a placeholder for shimmer
• Apply the effect with live data
• Conclusion
• Resources

Let’s analyze every step in detail.

Add Shimmer Library 

Add Shimmer Library to build.gradle :

// Cards Shimmer Animation
implementation 'com.facebook.shimmer:shimmer:0.5.0'

Create reasouces

Add shimmer background color to colors.xml:

<color name="shimmer_background">#dddddd</color>

Create a placeholder layout:

<androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_margin="@dimen/layout_margin_medium"
    app:cardBackgroundColor="@android:color/white"
    app:cardCornerRadius="@dimen/card_corner_radius"
    app:cardElevation="@dimen/layout_margin_none"
    android:foreground="?android:attr/selectableItemBackground"
    android:background="@android:color/white">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="@dimen/layout_margin_large"
        android:layout_gravity="center"
        android:orientation="vertical">

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="@dimen/item_image_view_160dp"
            android:scaleType="centerCrop"
            android:background="@color/shimmer_background"/>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_marginTop="@dimen/layout_margin_medium"
            android:layout_height="wrap_content"
            android:orientation="horizontal">

            <View
                android:layout_width="@dimen/card_width_45dp"
                android:layout_height="@dimen/item_image_view"
                android:background="@color/shimmer_background"
                android:layout_marginEnd="@dimen/padding_large"
                android:layout_marginRight="@dimen/padding_large"
                android:gravity="center_horizontal"
                android:orientation="vertical"
                android:layout_marginTop="@dimen/padding_medium">
            </View>

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="vertical"
                android:paddingBottom="@dimen/padding_large"
                android:paddingTop="@dimen/padding_medium">

                <View
                    android:layout_width="match_parent"
                    android:layout_height="@dimen/view_height_25dp"
                    android:layout_marginBottom="@dimen/layout_margin_small"
                    android:background="@color/shimmer_background"/>

                <View
                    android:layout_width="match_parent"
                    android:layout_height="@dimen/view_height_25dp"
                    android:background="@color/shimmer_background"/>

            </LinearLayout>
        </LinearLayout>
    </LinearLayout>
</androidx.cardview.widget.CardView>

Add shimmer in your fragment/activity layout resources file:

<com.facebook.shimmer.ShimmerFrameLayout
        android:id="@+id/shimmer_view_container"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_marginTop="15dp"
        android:orientation="vertical"
        shimmer:duration="800">

        <!-- Adding 7 rows of placeholders -->
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">
            <include layout="@layout/data_placeholder_layout" />
            <include layout="@layout/data_placeholder_layout" />
            <include layout="@layout/data_placeholder_layout" />
            <include layout="@layout/data_placeholder_layout" />
            <include layout="@layout/data_placeholder_layout" />
            <include layout="@layout/data_placeholder_layout" />
            <include layout="@layout/data_placeholder_layout" />
        </LinearLayout>

    </com.facebook.shimmer.ShimmerFrameLayout>

Apply Shimmer with LiveData

Declare live data variable in view model:

private val mutableShowShimmer = MediatorLiveData<Boolean>()
val showShimmer: MediatorLiveData<Boolean> = mutableShowShimmer

Handle progress in the view model:

compositeDisposable += eventPagedList
            .subscribeOn(Schedulers.io())
            .doOnSubscribe {
                mutableShowShimmer.value = true
            }.finally {
     mutableShowShimmer.value = false
}

Handle shimmer with observing the live data in fragment/activity:

eventsResultsViewModel.showShimmer
            .nonNull()
            .observe(viewLifecycleOwner, Observer {
                if (it) {
                    rootView.shimmer_view_container.startShimmer()
                } else {
                    rootView.shimmer_view_container.stopShimmer()
                }
                rootView.shimmer_view_container.isVisible = it
            })

GIF

Resources

Show shimmer progress in Android: https://medium.com/mindorks/android-design-shimmer-effect-fa7f74c68a93

Tags

Eventyay, open-event, Shimmer, Facebook, MVVM, Fossasia, GSoC, Android, Kotlin