Android ViewPager Lag

Question

Hello I have a viewpager with several pages(using a fragment state pager), and some pngs as backgrounds to those pages. I already followed the Displaying Bitmaps in the Ui (

Answer 1

I had similar problem.

I am showing tutorial-like pages. Each page is a full screen jpg.

At first, I put the pictures in res/drawablesfolder. The viewpager is very laggy when swiping it.

Then I move those jpgs to res/drawable-hdpi folder, the lag is gone.

I think different optimisations are done on the pictures based on folder. So we cannot put everything in res/drawable folder

Answer 2

Building up on @coderek answer I seem to have solved this by fetching bitmaps without scaling them for specific densities:

BitmapFactory.Options opts = new BitmapFactory.Options();
opts.inScaled = false;
Bitmap bitmap = BitmapFactory.decodeResource(getResources(), resource, opts);

((ImageView) view).setImageBitmap(bitmap);

Using an image from drawable folder in an xxhdpi device resulted in up to 8 times more memory being allocated!

P.S.:

You can also down sample the drawable if the resolution is too big:

opts.inSampleSize = 2;

Answer 3

I had a similar problem too and, in my case, the lagging was caused by the background picture of the layouts which was too large. I just resized the picture and the swiping lag was gone

Answer 4

Instead of moving to res/drawable-hdpi I moved the images to res/drawable-xxxhdpi. This instantly solved the problem.

Answer 5

I followed the answer of Coderek and moved it between the different

res/drawable-hdpi folders

drawable-xxxhdpi is what worked best for my project.

Answer 6

You may want to try viewPager.setOffScreenLimit(size) to the number of your pages. This will load all the fragments once and keep from reloading them while swiping.