Develop Reference

FragmentStatePagerAdapter memory issue

I'm making an application with the ViewPager class and with a FragmentStatePagerAdapter adapter. I've read that the difference between the mentioned adapter and FragmentPagerAdapter is that the later stores all pages in memory at once, whereas FragmentStatePagerAdapter has only 3 loaded in memory at any given time.
So, here is the issue. I have a ViewPager with about 50 pages. There is a fragment on each page with a single ImageView image(and some other elements). After scrolling through around 20 unique pages, I usually get the Out Of Memory Error. So, my question is: How am I supposed to configure FragmentStatePagerAdapter to only have about 3 pages loaded in memory at any given time? This is the code for my adapter:
mViewPager.setAdapter(new FragmentStatePagerAdapter(fm) {
#Override
public Fragment getItem(int position) {
Song song = mSongs.get(position);
return PlayFragment.newInstance(position);
}
#Override
public int getCount() {
return mSongs.size();
}
#Override
public void destroyItem(View collection, int position, Object o) {
View view = (View)o;
((ViewPager) collection).removeView(view);
view = null;
}
#Override
public Object instantiateItem(View context, int position) {
ImageView imageView = new ImageView(getApplicationContext());
imageView.findViewById(R.id.albumimage);
imageView.setImageBitmap(BitmapFactory.decodeResource(getResources(), position));
((ViewPager) context).addView(imageView);
return imageView;
}
});
The destroyItem and instantiateItem methods currently do nothing. I've added them after reading about this from someone else's question. There is no difference as of now if I have these two methods in my code or not.
I've read other questions similar to mine, but I have finally decided to ask a question after having attempted to solve the problem on my own with no good results.
I tried setting the ImageView to null in onDestroy(), but nothing happened.

Bitmap created by BitmapFactory.decodeResource(getResources(), position) has to be released manually by calling Bitmap.recycle()
https://developer.android.com/training/displaying-bitmaps/manage-memory.html

I've started using bitmaps as input for ImageView. The code below works fine.
albumimg = BitmapFactory.decodeFile(mSong.getImg());
mImg.setImageBitmap(albumimg);
mImg.setVisibility(View.VISIBLE);
And this in onDestroy() and onDestroyView():
if(albumimg != null) {`albumimg.recycle(); }`
Thanks for the help. :)

View Pager with Universal Image Loader Out of Memory Error

I am not really sure if a ViewPager with Universal Image Loader can/should be used as an alternate for a gallery like interface since I have run into an Out of Memory error while loading images from SD Card and viewing them in full screen mode. No matter what the number, it works all fine with a GridView but while viewing the images in the View Pager, each bitmap keeps eating up a lot of memory and after 10 or so images, it gives the out of memory error.
I have seen almost all the questions that have been posted here related to the Out of Memory Error while working with the Universal Image Loader and in each one of them, there has been a configurations error as the cause.
I dont know if I am using the wrong configurations or what but I have wasted a lot of time on it and am kind of stuck, any help/advice would be appreciated.
The configurations for the ImageLoader:
ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(getApplicationContext())
.memoryCache(new WeakMemoryCache())
.denyCacheImageMultipleSizesInMemory()
.discCacheFileNameGenerator(new Md5FileNameGenerator())
.imageDownloader(new ExtendedImageDownloader(getApplicationContext()))
.tasksProcessingOrder(QueueProcessingType.LIFO)
// .enableLogging() // Not necessary in common
.build();
The Display Image Options are:
options = new DisplayImageOptions.Builder()
.showImageForEmptyUri(R.drawable.image_for_empty_url)
.resetViewBeforeLoading()
.imageScaleType(ImageScaleType.IN_SAMPLE_INT)
.bitmapConfig(Bitmap.Config.RGB_565)
.displayer(new FadeInBitmapDisplayer(300))
.build();
I am using the example project that was given with the library but those settings wont work either, it just crashes after some time. My guess is that there is a specific callback where I have to recycle bitmaps from the views from that are not visible.
EDIT: I know its a memory leak, the views that are not visible are destroyed when they should be but the memory is not released as it should. Heres the implementation of the destroyItem callback, followed the tips given in different questions but still cant find the memory leak.
#Override
public void destroyItem(View container, int position, Object object) {
// ((ViewPager) container).removeView((View) object);
Log.d("DESTROY", "destroying view at position " + position);
View view = (View)object;
((ViewPager) container).removeView(view);
view = null;
}

It's probably not the best implementation to solve it, but it worked for me. Removing the ImageViews is not enough, so I decided to recycle bitmaps in 'destroyItem':
#Override
public void destroyItem(ViewGroup container, int position, Object object) {
View view = (View) object;
ImageView imageView = (ImageView) view.findViewById(R.id.image);
if (imageView != null) {
Bitmap bitmap = ((BitmapDrawable) imageView.getDrawable()).getBitmap();
bitmap.recycle();
bitmap = null;
}
((ViewPager) container).removeView(view);
view = null;
}
This does not clean the last 3 active pages when you leave the activity, although I hope that GC takes care of them.

Try to apply next suggestions:
Use ImageScaleType.EXACTLY
Enable caching on disc (in display options).
Finally try to use .discCacheExtraOptions(maxImageWidthForDiscCache, maxImageHeightForDiscCache, CompressFormat.PNG, 0);

Just posting this because this question is coming up on Google when searching for UIL and OOP. I had OOP problems no matter what configuration, what solved all my problems were the two classes RecyclingImageView and RecyclingBitmapDrawable from this sample project.

I also used the same library and had same error. As solution, i created a sparseArray to keep photoView instances. And use it like this:
private SparseArray<PhotoView> photoViewHolder;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
...
photoViewHolder = new SparseArray<PhotoView>();
...
}
private class GalleryPagerAdapter extends PagerAdapter {
#Override
public View instantiateItem(ViewGroup container, int position) {
PhotoView photoView = new PhotoView(container.getContext());
ImageHolder holder = new ImageHolder();
holder.position = position;
holder.loaded = false;
photoView.setTag(holder);
photoViewHolder.put(position, photoView);
// I used LazyList loading
loader.DisplayImage(items.get(position), photoView);
// Now just add PhotoView to ViewPager and return it
container.addView(photoView, LayoutParams.MATCH_PARENT,
LayoutParams.MATCH_PARENT);
return photoView;
}
#Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView((View) object);
photoViewHolder.remove(position);
}
#Override
public boolean isViewFromObject(View view, Object object) {
return view == object;
}
}
And to handle viewPager's listener:
pager.setOnPageChangeListener(new OnPageChangeListener() {
#Override
public void onPageScrollStateChanged(int position) {
}
#Override
public void onPageScrolled(int position, float arg1, int arg2) {
}
#Override
public void onPageSelected(int position) {
if(photoViewHolder.get(position) != null) {
ImageHolder holder = (ImageHolder)photoViewHolder.get(position).getTag();
// Do something...
}
}
});
Hope this helps...

I used kutothe's implementation from github issues page.

I had this problem when simply setting Uri to ImageView using: iv.setImageURI(Uri.fromFile(imgFile));
I had the same problem with Universal Image Loader, and I even looked for other Image Loaders out there, and found another good one called "Picasso", but it also had the same problem.
So what worked for me is using GestureImageView and setting gesture-image:recycle to true through XML, and load the images with the following code:
Drawable yourDrawable = null;
try {
InputStream inputStream = getActivity().getContentResolver().openInputStream(Uri.fromFile(img));
yourDrawable = Drawable.createFromStream(inputStream, Uri.fromFile(img).toString() );
inputStream.close();
} catch (FileNotFoundException e) {
yourDrawable = getResources().getDrawable(R.drawable.ic_launcher);
} catch (IOException e) {
e.printStackTrace();
}
if (yourDrawable != null)
iv.setImageDrawable(yourDrawable);
the reason it was crashing and giving OOM error is that the bitmaps aren't recycled when the image aren't displayed on the screen anymore, hence a memory leak occurs.
If there is another way to recycle the bitmap in the normal ImageView, that would be a better solution.
Hope I helped.

I know it's late, but maybe my answer will save someone's time. After hours and hours of trying to solve this issue (with almost every answer found on stack overflow) I finally solved it with Fresco image library. It'a a lib written by Facebook and it's primary goal is to use memory in efficient way. It's really great and my Out Of Memory Error disappeared. I highly recommend using it.
http://frescolib.org/

destroyItem being called when position ==2 why? android pagerAdapter

I have a very simple PagerAdapter that for some reason, removes the views at position 0 and
1 when it is scrolled to position 2.
Specifically, when I first run the app, there are 3 views. I scroll to position 2 and position 1's view will disappear. View 0 is still there. If I scroll to view 0 and back to view 2 and again back to view 0, View 0 suddenly disappears. I do the same again, and I can actually see view 0 being instantiated and immediately destroyed.
what is going on here?
Main Activity
public class MainActivity extends Activity {
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final MyPagerAdapter adapter = new MyPagerAdapter(this);
final ViewPager myPager = (ViewPager) findViewById(R.id.mypanelpager);
myPager.setAdapter(adapter);
myPager.setCurrentItem(1);
}
public class MyPagerAdapter extends PagerAdapter {
private Context ctx;
Calendar c = Calendar.getInstance();
int month = c.get(Calendar.MONTH);
int year = c.get(Calendar.YEAR);
ViewGroup collection;
public MyPagerAdapter (Context ctx){
this.ctx = ctx ;
}
#Override
public int getCount() {
return 3;
}
public Object instantiateItem(ViewGroup container, int position ){
this.collection = (ViewPager)container;
NewMonth monthObject = new NewMonth(ctx, month+position-1,2012);
View monthLayout = monthObject.newParentLayout;
collection.addView(monthLayout);
return monthLayout;
return addViewAt(position);
}
#Override
public void destroyItem(ViewGroup container, int position, Object object) {
collection.removeViewAt(position);
}
#Override
public Parcelable saveState() {
return null;
}
#Override
public boolean isViewFromObject(View view, Object arg1) {
return view==arg1;
}
}

You have to maintain all tabs in memory specifying the OffscreenPageLimit to N-1, in your case put this inside the onCreate method:
myPager.setOffscreenPageLimit(2);

Checkout populate() function from ViewPager source - it has clear checks then to remove currentIndex+1 and currentIndex-1 items. Removing is done based on view sizes and it seems to be entirely internal ViewPager logic. ViewPager source is located
<android sdk folder>\extras\android\support\v4\src\java\android\support\v4\view\ViewPager.jav‌​a
.
You might debug ViewPager to know that is happening exactly, but I wouldn't suggest so until You faced some serious issue with ViewPager. What's why: if you dig into ViewPager code it might lead You to write some hackish code (even not intentionally) on it based on its internal structure and not on its public interface and documentation. So, the main idea of data encapsulation would be ruined which is definitely not good (sadly, sometimes we need to do so in Android due to lack of documentation / unclear naming / android internal issues etc., check Code Complete by Steve McConnell for more details on good encapsulation etc.).

Here the key is that position is different then index. If they give you a position there is no guarantee that your collections haven't removed other positions.
Example:
Let's say your at position 2. destroyItem might have been called for position 0 which means in your collections now position 2 is actually at index 1. So your indexes will quickly become out of sync from your positions. The same thing happens with listview children. I would recommend using a sparseArray instead.
private final SparseArray<View> views = new SparseArray<>();
public View instantiateItem(ViewGroup container, final int position) {
...
views.put(position, view);
...
}
public void destroyItem(ViewGroup container, int position, Object object) {
View view = views.get(position);
if (view != null) {
container.removeView(view);
views.remove(position);
}
}

Is it possible to change the position of gridview images while swiping?

Myself trying to load the images(from webservice) in gridview and it was succesfully done.
I used Lazy Adapter to load all images from web service.
If i click on some image it should be displayed in next Activity and while swiping that image next image should be displayed. Any Ideas???

This can be relatively easy realised using a ViewPager, I'd say. Consider the flow as follows: When the user selects a list item, pass on a list of all the images (e.g. their URIs) and an index indicating the one selected to the activity containing the ViewPager. You can then initialise the ViewPager's adapter with the passed on list and set the current item to display to the index.
Have a look at the API demos for some more hints on how to use a ViewPager, or read the blog post on developers.android.com. In stead of feeding Fragments as Views to the ViewPager, simply instantiate an ImageView - you may find this Q/A on SO useful for some pointers on how to do that. Also, probably equally important to read through is the documentation on PagerAdapter.
//Edit: Some pointers for coding up above suggestion:
Have your onItemClick create a new Intent, add the relevant data for retrieving the images as extra as well as the selected index and start the Activity:
#Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Intent intent = new Intent(this, ImageViewer.class);
intent.putExtra(PAGE_POSITION, position);
intent.putStringArrayListExtra(IMAGE_LIST, mImages)
// or add a serializable, e.g. an ArrayList<T> with your POJOs
intent.putExtra(IMAGE_LIST, mImages);
startActivity(intent);
}
In your ImageViewer Activity containing the ViewPager, retrieve all the extras and initialise the ViewPager to the given position/index:
if (getIntent() != null && getIntent().getExtras() != null {
mImagePosition = getIntent().getExtras().getInt(PAGE_POSITION, 0);
mImageList = getIntent().getExtras().getStringArrayList(IMAGE_LIST);
// or if you used Serializables
mImageList = (ArrayList<T>) getIntent().getExtras().getSerializable(IMAGE_LIST);
mViewPager.setAdapter(new ImagePagerAdapter());
mViewPager.setCurrentItem(mImageIndex);
}
In the ImagePaderAdapter you instantiate the ImageViews containing the images you want to display. There are tons of examples out there, but it'll look something like this in the basis:
private class ImagePagerAdapter extends PagerAdapter {
public int getCount() {
return mImageList == null ? 0 : mImageList.size();
}
public Object instantiateItem(View pager, int position) {
if (mInflater == null) mInflater = (LayoutInflater) container.getContext().getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
View view = mInflater.inflate(R.layout.image_pager_item_layout, null, false);
ImageView photoImageView = (ImageView) view.findViewById(R.id.photo_imageview);
mImageLoader().loadImage(mImageList.get(position), photoImageView);
((ViewPager) pager).addView(view, 0);
return view;
}
public void destroyItem(View pager, int position, Object object) {
((ViewPager) pager).removeView((View) object);
}
public boolean isViewFromObject(View view, Object object) {
return view.equals(object);
}
public void finishUpdate(View container) { }
public void restoreState(Parcelable state, ClassLoader loader) { }
public void startUpdate(View container) { }
public Parcelable saveState() { return null; }
}
Note that I have not tested the code above, nor is it meant to be complete. For instance, I assume you know how to get a reference to a LayoutInflater yourself and have a 'lazy' image loader that asynchronously sets an image against an ImageView. The image_pager_item_layout file can simply be an ImageView, but also a more complex hierarchy of views inside a ViewGroup (like with ListView and GridView), e.g. you can easily add an caption to images. It's quite similar to

Android: Viewpager and FragmentStatePageAdapter

I'm designing an app that allows users to flip between multiple pages in a ViewPager. I've been struggling trying to figure out how it is possible to remove a Fragment instance from a page when it is no longer visible on screen, cache it (to, say, a HashMap), and then restore it so that when the user flips back to that page, the views and everything else in it will be in the same state it was before removal. For example, my first page is a login screen that makes certain layout elements on that particular page visible/invisible on a successful login. When I flip forward enough pages then flip back to the first page, the layout is reset. This becomes more of a problem for another one of my pages which contains a huge, horizontal/vertical scrolling grid of data that I use a thread in the background to draw when it initializes. I use a progress dialog to notify the user of loading progress and that becomes really annoying everytime I have to load it.
So I did some research...
I browsed through the source code for FragmentStatePageAdapter and in the destroyItem() callback, the state of the Fragment instance being removed is saved to an ArrayList. When a new instance of the Fragment is being created in the instantiateItem() callback, if an instance of an item doesn't already exist (they keep track of this by using an ArrayList), a new Fragment instance is created and its saved state is initialized with the corresponding Fragment.SavedState data. Unfortunately, this data does not include the state that the Views were in although I noticed that for pages with a GridView/ListView, the state of the Views were somehow restored (if I scrolled to some random position, flipped a few pages and came back, it would not be reset).
According to the API:
The saved state can not contain dependencies on other fragments --
that is it can't use putFragment(Bundle, String, Fragment) to store a
fragment reference because that reference may not be valid when this
saved state is later used. Likewise the Fragment's target and result
code are not included in this state.
Being a noob to Android, I'm not quite sure I understand the last statement.
That being said, is there any way to cache View state? If not, I think I'll just go ahead and go with leaving all the fragment pages in memory.

I had the same problem problem and solved it by implementing these two functions
public void onSaveInstanceState (Bundle outState)
public void onActivityCreated (Bundle savedInstanceState)
on the fragments that I wanted to save. On the first function, you should save in the Bundle the date that you need to restore the views ( in my case I had a bunch of spinner so I used
an int array to save their positions). The second function, which is called when restoring your fragment, is where you implement the restoring process.
I hope this helps. I also made my adapter to inherit from FragmentStatePageAdapter but I am not sure that this is mandatory.

Listing of main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView android:text="Page 1" android:id="#+id/textViewHeader"
android:layout_width="fill_parent" android:layout_height="wrap_content"
android:gravity="center" android:padding="10dip" android:textStyle="bold"></TextView>
<android.support.v4.view.ViewPager
android:layout_width="fill_parent" android:layout_height="fill_parent"
android:id="#+id/viewPager" />
</LinearLayout>
Setting up the ViewPager
ViewPager viewPager = (ViewPager) findViewById(R.id.viewPager);
MyPagerAdapter adapter = new MyPagerAdapter(this);
viewPager.setAdapter(adapter);
The PagerAdapter
#Override
public void destroyItem(View view, int arg1, Object object) {
((ViewPager) view).removeView((View)object);
}
#Override
public int getCount() {
return views.size();
}
#Override
public Object instantiateItem(View view, int position) {
View view = views.get(position);
((ViewPager) view).addView(view);
return view;
}
#Override
public boolean isViewFromObject(View view, Object object) {
return view == object;
}
look here for more details view pager example

Looking at the various documentation pieces, my best guess is that the views you are creating do not have an ID attached to them. Assuming that the fragment's saved state is created from Fragment.onSaveInstanceState, then the fragment will automatically save any view's state that has an id. You probably have a default id associated with your ListView/GridView if you created them from a layout file. You can also associate an id with the views by calling setId.
Also, for your custom filled fragment, you may also have to do something custom in onSaveInstanceState.

Here's an example of how I implemented caching in PagerAdapter. After filling the cache all future view requests are served from cache, only data is replaced.
public class TestPageAdapter extends PagerAdapter{
private int MAX_SIZE = 3;
private ArrayList<SoftReference<View>> pageCache = new ArrayList<SoftReference<View>>(3);
public TestPageAdapter(Context context){
// do some initialization
}
#Override
public int getCount() {
// number of pages
}
private void addToCache(View view){
if (pageCache.size() < MAX_SIZE){
pageCache.add(new SoftReference<View>(view));
} else {
for(int n = (pageCache.size()-1); n >= 0; n--) {
SoftReference<View> cachedView = pageCache.get(n);
if (cachedView.get() == null){
pageCache.set(n, new SoftReference<View>(view));
return;
}
}
}
}
private View fetchFromCache(){
for(int n = (pageCache.size()-1); n>= 0; n--) {
SoftReference<View> reference = pageCache.remove(n);
View view = reference.get();
if (view != null) {
return view;
}
}
return null;
}
#Override
public Object instantiateItem(View collection, int position) {
View view = fetchFromCache();
if (view == null) {
// not in cache, inflate manually
LayoutInflater inflater = (LayoutInflater) collection.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
view = inflater.inflate(R.layout.page, null);
}
setData(view, position);
((ViewPager) collection).addView(view, 0);
return view;
}
private void setData(View view, int position){
// set page data (images, text ....)
}
public void setPrimaryItem(ViewGroup container, int position, Object object) {
currentItem = (View)object;
}
public View getCurrentItem() {
return currentItem;
}
#Override
public boolean isViewFromObject(View view, Object object) {
return view == ((View) object);
}
#Override
public void destroyItem(View collection, int arg1, Object view) {
((ViewPager) collection).removeView((View) view);
addToCache((View) view);
}
}

I also ran into this problem when I was using PagerSlidingTabStrip and using and instance of FragmentPagerAdapter, switching to FragmentStatePagerAdapter definitely worked.
Then I use onSaveInstanceState() to save sate