ViewPager unable to load images lazily with Picasso

Question

I have a FragmentActivity in the first tab of a TabHost, and the FragmentActivity itself holds a ViewPager.

The ViewPager's setAdapter() method sets a FragmentPagerAdapter with a set of Fragments. The goal is to have swipeable images in the first pane of the TabHost.

To test it, I was loading a bunch of images that I had kept locally in the project's drawable directory. Everything worked beautifully.

After having tested this initial setup, I'm downloading a bunch of image URLs' off a REST web service. I want these images to load lazily in the ViewPager, and I tried calling Picasso's load() method in three places:

The onCreateView() method of the ViewPager's Fragments (the same place where I was earlier loading images from the local drawable directory).

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, 
    Bundle savedInstanceState) {                

    View myFragmentView = inflater.inflate(R.layout.layout_fragment, container, false);

    ImageView imageView = (ImageView)getView().findViewById(R.id.fragment_image);
    String url = getArguments().getString(IMAGE_RESOURCE_URL);
    Context context = getActivity();
    Picasso.with(context).load(url).fit().into(imageView);

    return myFragmentView;
}

The onViewCreated() method of the ViewPager's Fragments.

@Override
public void onViewCreated(View view, Bundle savedInstanceState){

    Context context = getActivity();
    String url = getArguments().getString(IMAGE_RESOURCE_URL);
    ImageView imageView = (ImageView)view.findViewById(R.id.fragment_image);
    Picasso.with(context).load(url).fit().into(imageView);      

}

The onInstantiateItem() method of the FragmentPagerAdapter.

@Override
public Object instantiateItem(ViewGroup container, int position) {

    View v = inflater.inflate(R.layout.layout_fragment, container, false);
    Context context = Tab1Activity.this;
    String url = getItem(position).getArguments().getString("IMAGE_RESOURCE_URL");
    ImageView imageView = (ImageView)v.findViewById(R.id.fragment_image);
    Picasso.with(context).load(url).fit().into(imageView);
    return v;
}

None of these methods worked. I know that its not a problem with Picasso because the other day I tried using Picasso in a ListView and it worked like a charm. What am I doing wrong ?

score 1 · Accepted Answer · answered Feb 08 '14 at 15:18

1

Your first approach should work fine... if you implement it correctly. I would expect your code to crash with a NullPointerException.

Replace:

ImageView imageView = (ImageView)getView().findViewById(R.id.fragment_image);

with:

ImageView imageView = (ImageView)myFragmentView.findViewById(R.id.fragment_image);

answered Feb 08 '14 at 15:18

CommonsWare

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Well, I am an idiot. Thank you so much, CommonsWare. Though Picasso still doesn't work even after I corrected my mistake. Every time I try it with Picasso the LogCat shows a strange WARNING message: "VFY: unable to resolve static method 571: Landroid/net/TrafficStats;.setThreadStatsTag (I)V". I ended up doing it with Volley which works perfectly. – Yash Sampat Feb 11 '14 at 06:32
@JohnG: That's just a warning, indicating that you're running on a device that lacks that particular class (`TrafficStats`) or method (`setThreadStatsTag()`). Unless you crashed, Picasso would have correctly skipped over that statement. – CommonsWare Feb 11 '14 at 12:32
My problem is similar but this not help, check my SO question @CommonsWare, please. http://stackoverflow.com/questions/21890598/first-time-error-loading-picture-with-picasso Thanks in advance. – wendigo Feb 19 '14 at 19:56

score 0 · Answer 2 · answered Feb 08 '14 at 15:24

Your lazy loader should work in the context of the

Fragment.createView()

where the Fragment is one of a collection being paged by the ViewPager and the FragmentpagerAdapter

That is your option one.

I use another lazyloader that manages local memcache and local filesys cache for the bitmaps needed to load the images. at the time of the "OnCreateView()" it will go to the network to get the URL for the loader if the bitmap is not already cached.

ViewPager unable to load images lazily with Picasso

2 Answers2

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