Android ViewStub using Data Binding

ViewStub:

A ViewStub is an invisible, zero-sized View that can be used to lazily inflate layout resources at runtime.

When a ViewStub is made visible, or when inflate() is invoked, then layout resource is inflated. ViewStub replaces itself in its parent with the inflated View or Views. ViewStub exists in the view hierarchy until setVisibility(int) or inflate() is invoked.

You can reduce memory usage and speed up rendering by loading the views only when they are needed.

Define ViewStub in XML file

<?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>
        <import type="android.view.View" />     
    </data>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

         <!--Other Views-->

        <ViewStub
            android:id="@+id/nav_drawer_user_view"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />

         <!--Other Views-->

    </LinearLayout>
</layout>

<?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>

</data>

<LinearLayout

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:orientation="vertical">

<ViewStub

android:id="@+id/nav_drawer_user_view"

android:layout_width="match_parent"

android:layout_height="wrap_content" />

</LinearLayout>

</layout>

Inflate ViewStub:

We can specify layout at run time (viewStub!!.layoutResource) or in XML layout (android: layout) attribute. A ViewStub can be load by using visible, or inflate().

import android.databinding.DataBindingUtil
import android.os.Bundle
import android.support.v4.app.Fragment
import android.view.View
import android.view.ViewStub
import com.webkul.mobikul.fragments.NavDrawerStartFragment
import com.webkul.mobikulmp.databinding.LayoutSellerMenusBinding


class ViewStubs : Fragment() {

    override fun onActivityCreated(savedInstanceState: Bundle?) {
        super.onActivityCreated(savedInstanceState)

        if(some condition){
              updateMenu()
            }
    }

    fun updateMenu() {

        mContentViewBinding.navDrawerUserView.viewStub!!
                .setOnInflateListener(
                        object : ViewStub.OnInflateListener {
                            override fun onInflate(stub: ViewStub, inflated: View) {

          val binding: LayoutUserMenusBinding? = DataBindingUtil.bind(inflated)

                            }
                        })
        //Set layout resouce
        mContentViewBinding.navDrawerUserView.
                            viewStub!!.layoutResource = R.layout.layout_user_menus

        if (!mContentViewBinding.navDrawerUserView.isInflated) {
            // inflate you layout after setting layout resouce
            mContentViewBinding.navDrawerUserView.viewStub!!.inflate()

        }
    }
}

import android.databinding.DataBindingUtil

import android.os.Bundle

import android.support.v4.app.Fragment

import android.view.View

import android.view.ViewStub

import com.webkul.mobikul.fragments.NavDrawerStartFragment

import com.webkul.mobikulmp.databinding.LayoutSellerMenusBinding

class ViewStubs : Fragment() {

override fun onActivityCreated(savedInstanceState: Bundle?) {

super.onActivityCreated(savedInstanceState)

if(some condition){

updateMenu()

}

fun updateMenu() {

mContentViewBinding.navDrawerUserView.viewStub!!

.setOnInflateListener(

object : ViewStub.OnInflateListener {

override fun onInflate(stub: ViewStub, inflated: View) {

val binding: LayoutUserMenusBinding? = DataBindingUtil.bind(inflated)

}

})

//Set layout resouce

mContentViewBinding.navDrawerUserView.

viewStub!!.layoutResource = R.layout.layout_user_menus

if (!mContentViewBinding.navDrawerUserView.isInflated) {

// inflate you layout after setting layout resouce

mContentViewBinding.navDrawerUserView.viewStub!!.inflate()

}

yogendra singh 31 May 2019

. . .

2 comments

Vedesh Kumar (Moderator) May 31, 2019 at 6:17 pm

I can inflate the views inside a LinearLayout and can get the same results. Why use this ViewStub?

Friend Jul 10, 2019 at 6:00 pm
UI performance. There are times when the UI component i.e. activity or fragment has too many UI elements but all the elements might not be visible every time. So if you are concerned about UI performance when your UI component has many view/views-group then one can have ViewStub which is lazily inflated when it’s visibility is enabled.

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Android ViewStub using Data Binding

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