Recyclerview scroll slow

GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together. Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community. Already on GitHub? Sign in to your account. I create that issue here because I need some help from the Nativescript team to figure out what is going on.

I needed to fix issues in RadListView but as it is not open source I had to start writing my own. When I run my app on android the first time I can see a first scroll is lagging.

Once that first scroll is done the list view is really really fast faster than Nativescript list view. If I close my app with "back" and open it again, It won't lag. After some tests the lag clearly comes from the View "loading" properties apply, nativeView creation Also this does not seem to happen that much with Nativescript ListView which I really don't understand.

I do see a lag but seems really "lighter". Want to back this issue? Post a bounty on it! We accept bounties via Bountysource. I ran a LOT of profiling tests. What I see is that my onCreateViewHolder method can take very different amount of time. For the exact same template it can take from 7ms to 40ms. As a comparaison if I inflate a TextView it takes 7ms. I tried with the latest tns-android hoping the latest v8 might make a difference, but it doesn't.

If by first run, you mean the first time it loads that screen, then yeah this is unfortunately normal behavior on NativeScript Android.So I decided to share my problems and my solutions.

I have a vertical RecyclerView that every item has a photo slider, some texts, a rating bar, a favorite image button, and a button. The first thing is about RecyclerView initializing. Another method is ItemViewCacheSize. Set the number of offscreen views to retain before adding them to the potentially shared recycled view pool.

The offscreen view cache stays aware of changes in the attached adapter, allowing a LayoutManager to reuse those views unmodified without needing to return to the adapter to rebind them. RecyclerView will attempt to synthesize visible structural change events for adapters that report that they have stable IDs when this method is used.

This can help for the purposes of animation and visual object persistence but individual item views will still need to be rebound and relaid out. These methods help you to improve your RecyclerView performance and maybe they could solve your all problems but in my case, my list scrolled with a bad lag especially on Samsung devices. After 2 days I found the problem, unfortunately, it was about ConstraintLayout. I design my items layout with ConstraintLayout and because of many constrained tags it was heavy to inflate, so I change it to Linear and Relative layout and most of my problems solved.

Here you can see the performance of them:. RecyclerView with ConstraintLayout. RecyclerView without ConstraintLayout. The second problem is some first items scrolled slowly because onCreateViewHolder called for the first 6 items. So we can tell RecyclerView to load all first 6 items at the first initializing. But How? PreCachingLayoutManager is the solution. We can create a layout manager to load some offscreen out of screen items at the first time.

As you can see there is a method named setExtraLayoutSpace with a parameter. But be careful, extending the extra layout space is especially expensive. Here we have a vertical RecyclerView with some Horizontal list in each item. These Horizontal lists are PhotoSlider and if you search about how to implement PhotoSlider you find many libraries have been implemented by ViewPager.

But in this case that we have so many items, and also each item has many ViewPagers, so we faced with a bunch of Fragments to show just some pictures.

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We have some optimization here to. When the user swipes the side-wise the inner RecyclerView recycles the views and gives you a smooth scroll. But this is not the case when the user scrolls vertically.UI Rendering is the act of generating a frame from your app and displaying it on the screen.

Slow rendering

To ensure that a user's interaction with your app is smooth, your app should render frames in under 16ms to achieve 60 frames per second why 60fps? If your app suffers from slow UI rendering, then the system is forced to skip frames and the user will perceive stuttering in your app.

We call this jank. To help you improve app quality, Android automatically monitors your app for jank and displays the information in the Android vitals dashboard. For information on how the data is collected, see Play Console docs. If your app is experiencing jank, this page provides guidance on diagnosing and fixing the problem.

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Pinpointing the code in your app that is causing jank can be difficult. This section describes three methods for identifying jank:.

Visual inspection lets you quickly run through all the use-cases in your app in a few minutes, but it doesn't provide as much detail as Systrace. Systrace provides more details, but if you ran Systrace for all the use-cases in your app, you'd be flooded with so much data that it'd be difficult to analyze.

Both visual inspection and systrace detect jank on your local device.

recyclerview scroll slow

If your jank cannot be reproduced on local devices, you can build custom performance monitoring to measure specific parts of your app on devices running in the field. Visual inspection helps you identify the use-cases that are producing jank. To perform a visual inspection, open your app and manually go through the different parts of your app and look out for UI that is janky.

Here are some tips when performing visual inspections:. Once you've found use-cases that produce jank, you might have a good idea of what is causing the jank in your app. But if you need more information, you can use Systrace to drill down further. Although Systrace is a tool that shows what the entire device is doing, it can be useful for identifying jank in your app.

Systrace has minimal system overhead, so you will experience realistic jankiness during instrumentation. Record a trace with Systrace while performing the janky use-case on your device.

See the Systrace Walkthrough for instructions on how to use Systrace.

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The systrace is broken up by processes and threads. Look for your app's process in Systrace, which should look like figure 1. Figure 1 : systrace. After looking at the systrace output, there might be methods in your app that you suspect are causing jank.

For an example, if the timeline shows that a slow frame is caused by RecyclerView taking a long time, you can add Trace markers to the relevant code and re-run systrace for more information. In the new systrace, the timeline will show when your app's methods are called and how long they took to execute. If systrace doesn't show you details about why UI thread work is taking for a long time, then you'll need to use Android CPU Profiler to record either a sampled or instrumented method trace.

Generally, method traces are not good for identifying jank because they produce false-positive janks due to heavy overhead and they can't see when threads are running vs blocked. But, method traces can help you identify the methods in your app are taking the most time.

After identifying those methods, add Trace markers and re-run systrace to see whether those methods are causing jank.

For more information, see Understanding Systrace. If you can't reproduce jank on a local device, you can build custom performance monitoring into your app to help identify the source of jank on devices in the field.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

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My adapter have a pattern implementation only for inflate the layout. The problem is the poor scrolling performance. This in a RecycleView with only 8 items. In some tests I verified that in Android L this problem does not occurs.

recyclerview scroll slow

But in the KitKat version the decreasing of performance is evident. I've recently faced the same issue, so this is what I've done with the latest RecyclerView support library:. Replace a complex layout nested views, RelativeLayout with the new optimized ConstraintLayout.

Add to the dependencies:. If possible, make all elements of the RecyclerView with the same height. And add:. Use the default RecyclerView drawing cache methods and tweak them according to your case. You don't need third party library to do so:. If you use many imagesmake sure their size and compression are optimal. Scaling images may also affect the performance. There are two sides of the problem - the source image used and the decoded Bitmap. The most important part is specifying inPreferredConfig - it defines how many bytes will be used for each pixel of the image.

Keep in mind that this is a preferred option.

recyclerview scroll slow

If the source image has more colors, it will still be decoded with a different config. Make sure onBindViewHolder is as cheap as possible. You can set OnClickListener once in onCreateViewHolder and call through an interface a listener outside of the Adapter, passing the clicked item. This way you don't create extra objects all the time.SmoothScroller extends Object.

Base class for smooth scrolling. Handles basic tracking of the target view position and provides methods to trigger a programmatic scroll. Holds information about a smooth scroll request by a RecyclerView. An interface which is optionally implemented by custom RecyclerView. LayoutManager to provide a hint to a RecyclerView.

SmoothScroller about the location of the target position. This method was deprecated in API level Use jumpTo int. Returns true if SmoothScroller has been started but has not received the first animation callback yet. RecyclerView will call this method each time it scrolls until it can find the target position in the layout. Compute the scroll vector for a given target position.

This method can return null if the layout manager cannot calculate a scroll vector for the given position e.

SmoothScroller should check dx, dy and if scroll should be changed, update the provided RecyclerView. Action to define the next scroll. Called when the target position is laid out. This is the last callback SmoothScroller will receive and it should update the provided RecyclerView. Action to define the scroll details towards the target view. Stops running the SmoothScroller in each animation callback.

Note that this does not cancel any existing RecyclerView.

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Action updated by onTargetFound android. View, RecyclerView. State, SmoothScroller.

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Content and code samples on this page are subject to the licenses described in the Content License. The second Android 11 Developer Preview is now available, test it out and share your feedback. Android Developers. LinearSmoothScroller RecyclerView. SmoothScroller implementation which uses a LinearInterpolator until the target position becomes a child of the RecyclerView and then uses a DecelerateInterpolator to slowly approach to target position.

See also: LinearSmoothScroller.

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SmoothScroller added in version See also: findViewByPosition int. See also: getChildCount. See also: getChildLayoutPosition android. See also: scrollToPosition int. See also: stop.RecyclerViewPreloader can automatically load images just ahead of where a user is scrolling in a RecyclerView. To use the RecyclerView integration library, add a dependency on it in your build.

To use the RecyclerView integration library you need to follow a couple of steps:. After you add the gradle dependency, you next need to create a PreloadSizeProvider. The PreloadSizeProvider is responsible for making sure your RecyclerViewPreloader loads images in the same size as those loaded by your adapters onBindViewHolder method.

Glide provides two built in implementations of PreloadSizeProvider :. If you are using a fixed size to load your images, typically FixedPreloadSizeProvider is simplest:.

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The next step is to implement your PreloadModelProvider. The PreloadModelProvider performs two actions. Second it takes a Model and produces a Glide RequestBuilder that will be used to preload the given Model into memory.

Your PreloadModelProvider implementation might then look like this:. If you have trouble getting these cache keys to match, see the debugging page. If you have nothing to preload for a given position, you can return an empty list from getPreloadItems. Using 10 for maxPreload is just a placeholder, for a detailed discussion on how to pick a number, see the section immediately below this one. The maxPreload is an integer that indicates how many items you want to preload. The optimal number will vary by your image size, quantity, the layout of your RecyclerView and in some cases even the devices your application is running on.

A good starting point is to pick a number large enough to include all of the images in two or three rows. An overly small number will prevent you from loading enough images ahead of time.

recyclerview scroll slow

The final step, once you have your RecyclerViewPreloader is to add it as a scroll listener to your RecyclerView :. Adding the RecyclerViewPreloader as a scroll listener allows the RecyclerViewPreloader to automatically load images ahead of the direction the user is scrolling in and detect changes of direction or velocity.

Documentation for Glide v4.As we already know that recyclerView has a smooth scrolling by itself but when we need to put recyclerView within any scrollView it will not work like the below code snippet:. The solution for this is we need to use nestedScrollView instead of scrollview like the below code snippet:. Now what kinda problem occurred when we used nestedScrollView and put recyclerView inside nestedScrollViewit scrolls at various speeds depending on gestures.

The scrolling feature will not be smooth. So to fix this issue all you have to do after setting your adapter. Now your recyclerview will work with smooth scrolling….

I hope this article is helpful. If you think something is missing, have questions, or would like to give feedback, go ahead and leave a comment below. Sharing the knowledge is Caring Thanks for reading this article. Be sure to clap to recommend this article if you found it helpful. It means a lot to me. Sign in.

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Archive About Submit your article. Danish Amjad Follow. Solution: The solution for this is we need to use nestedScrollView instead of scrollview like the below code snippet:. So to fix this issue all you have to do after setting your adapter put this line ViewCompat. Make Bottom Navigation without animation like youtube, Instagram.

RecyclerView - Infinite/Endless Scroll Tutorial - Android Pagination With Load More (in Hindi)

Sharing the knowledge is Caring :- Thanks for reading this article. Senior Software Engineer — Working on Android. Email: Dani. AndroidPub Follow. See responses More From Medium. More from AndroidPub. Wajahat Karim in AndroidPub.

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