I have a RecyclerView adapter that looks like this:
public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.ViewHolder> {
private static Context context;
private List<Message> mDataset;
public RecyclerAdapter(Context context, List<Message> myDataset) {
this.context = context;
this.mDataset = myDataset;
}
public static class ViewHolder extends RecyclerView.ViewHolder implements View.OnCreateContextMenuListener, View.OnClickListener {
public TextView title;
public LinearLayout placeholder;
public ViewHolder(View view) {
super(view);
view.setOnCreateContextMenuListener(this);
title = (TextView) view.findViewById(R.id.title);
placeholder = (LinearLayout) view.findViewById(R.id.placeholder);
}
}
#Override
public RecyclerAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.message_layout, parent, false);
ViewHolder vh = new ViewHolder((LinearLayout) view);
return vh;
}
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
Message item = mDataset.get(position);
holder.title.setText(item.getTitle());
int numImages = item.getImages().size();
if (numImages > 0) {
View test = LayoutInflater.from(holder.placeholder.getContext()).inflate(R.layout.images, holder.placeholder, false);
ImageView image = (ImageView) test.findViewById(R.id.image);
Glide.with(context)
.load("http://www.website.com/test.png")
.fitCenter()
.into(image);
holder.placeholder.addView(test);
}
}
#Override
public int getItemCount() {
return mDataset.size();
}
}
However, some of the items in the RecyclerView are showing images when they shouldn't be. How can I stop this from happening?
I do the check if (numImages > 0) { in onBindViewHolder(), but that's still not stopping it from showing images for items that shouldn't have images.
You should set imageView.setImageDrawable (null)
In onBindViewHolder() before setting the image using glide.
Setting image drawable to null fix the issue.
Hope it helps!
The problem is in onBindViewHolder, here:
if (numImages > 0) {
View test = LayoutInflater.from(holder.placeholder.getContext()).inflate(R.layout.images, holder.placeholder, false);
ImageView image = (ImageView) test.findViewById(R.id.image);
Glide.with(context)
.load("http://www.website.com/test.png")
.fitCenter()
.into(image);
holder.placeholder.addView(test);
}
If numImages is equal to 0, you're simply allowing the previously started load into the view you're reusing to continue. When it finishes, it will still load the old image into your view. To prevent this, tell Glide to cancel the previous load by calling clear:
if (numImages > 0) {
View test = LayoutInflater.from(holder.placeholder.getContext()).inflate(R.layout.images, holder.placeholder, false);
ImageView image = (ImageView) test.findViewById(R.id.image);
Glide.with(context)
.load("http://www.website.com/test.png")
.fitCenter()
.into(image);
holder.placeholder.addView(test);
} else {
Glide.clear(image);
}
When you call into(), Glide handles canceling the old load for you. If you're not going to call into(), you must call clear() yourself.
Every call to onBindViewHolder must include either a load() call or a clear() call.
I also had issues with RecyclerView showing wrong images. This happens because RecyclerView is not inflating view for every new list item: instead list items are being recycled.
By recycling views we can ruffly understand cloning views. A cloned view might have an image set from the previous interaction.
This is especially fair if your are using Picasso, Glide, or some other lib for async loading. These libs hold reference to an ImageView, and set an image on that refference when image is loaded.
By the time the image gets loaded, the item view might have gotten cloned, and the image is going to be set to the wrong clone.
To make a long story short, I solved this problem by restricting RecyclerView from cloning my item views:
setIsRecyclable(false)in ViewHolder constructor.
Now RecyclerView is working a bit slower, but at least the images are set right.
Or else cansel loading image in onViewRecycled(ViewHolder holde)
The issue here is that, as you are working with views that are going to be recycled, you'll need to handle all the possible scenarios at the time your binding your view.
For example, if you're adding the ImageView to the LinearLayout on position 0 of the data source, then, if position 4 doesn't met the condition, its view will most likely have the ImageView added when binding position 0.
You can add the content of R.layout.images content inside your
R.layout.message_layout layout's R.id.placeholder and showing/hiding the placeholder depending on the case.
So, your onBindViewHolder method would be something like:
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
Message item = mDataset.get(position);
holder.title.setText(item.getTitle());
int numImages = item.getImages().size();
if (numImages > 0) {
holder.placeholder.setVisivility(View.VISIBLE);
ImageView image = (ImageView)holder.placeholder.findViewById(R.id.image);
Glide.with(context)
.load("http://www.website.com/test.png")
.fitCenter()
.into(image);
}else{
holder.placeholder.setVisibility(View.INVISIBLE);
}
}
Sometimes when using RecyclerView, a View may be re-used and retain the size from a previous position that will be changed for the current position. To handle those cases, you can create a new [ViewTarget and pass in true for waitForLayout]:
#Override
public void onBindViewHolder(VH holder, int position) {
Glide.with(fragment)
.load(urls.get(position))
.into(new DrawableImageViewTarget(holder.imageView,/*waitForLayout=*/ true));
https://bumptech.github.io/glide/doc/targets.html
I also had the same problem and ended with below solution and it working fine for me..
Have your hands on this solution might be work for you too (Put below code in your adapter class)-
If you are using Kotlin -
override fun getItemId(position: Int): Long {
return position.toLong()
}
override fun getItemViewType(position: Int): Int {
return position
}
If you are using JAVA -
#Override
public long getItemId(int position) {
return position;
}
#Override
public int getItemViewType(int position) {
return position;
}
This works for me in onBindViewHolder!
if(!m.getPicture().isEmpty())
{
holder.setIsRecyclable(false);
Picasso.with(holder.profile_pic.getContext()).load(m.getPicture()).placeholder(R.mipmap.ic_launcher_round).into(holder.profile_pic);
Animation fadeOut = new AlphaAnimation(0, 1);
fadeOut.setInterpolator(new AccelerateInterpolator());
fadeOut.setDuration(1000);
holder.profile_pic.startAnimation(fadeOut);
}
else
{
holder.setIsRecyclable(true);
}
I was having same issue I solved by writing holder.setIsRecyclable(false).Worked for me.
#Override
public void onBindViewHolder(#NonNull RecylerViewHolder holder, int position) {
NewsFeed currentFeed = newsFeeds.get(position);
holder.textView.setText(currentFeed.getNewsTitle());
holder.sectionView.setText(currentFeed.getNewsSection());
if(currentFeed.getImageId() == "NOIMG") {
holder.setIsRecyclable(false);
Log.v("ImageLoad","Image not loaded");
} else {
Picasso.get().load(currentFeed.getImageId()).into(holder.imageView);
Log.v("ImageLoad","Image id "+ currentFeed.getImageId());
}
holder.dateView.setText(getModifiedDate(currentFeed.getDate()));
}
override fun getItemId(position: Int): Long {
return position.toLong()
}
override fun getItemViewType(position: Int): Int {
return position
}
This Works for Me
I Had the same issue and i fixed it like this:
GOAL : onViewAttachedToWindow
#Override
public void onViewAttachedToWindow(Holder holder) {
super.onViewAttachedToWindow(holder);
StructAllItems sfi = mArrayList.get(position);
if (!sfi.getPicHayatParking().isEmpty()) {
holder.viewFliperMelk.addSlider(new TextSliderView(mContext.getApplicationContext()).image(T.GET_MELK_IMAGE + '/' + sfi.getPicHayatParking() + ".jpg").setScaleType(BaseSliderView.ScaleType.CenterCrop));
}
if (!sfi.getPicSleepRoom().isEmpty()) {
holder.viewFliperMelk.addSlider(new TextSliderView(mContext.getApplicationContext()).image(T.GET_MELK_IMAGE + '/' + sfi.getPicSleepRoom() + ".jpg").setScaleType(BaseSliderView.ScaleType.CenterCrop));
}
if (!sfi.getPicSalonPazirayi().isEmpty()) {
holder.viewFliperMelk.addSlider(new TextSliderView(mContext.getApplicationContext()).image(T.GET_MELK_IMAGE + '/' + sfi.getPicSalonPazirayi() + ".jpg").setScaleType(BaseSliderView.ScaleType.CenterCrop));
}
if (!sfi.getPicNamayeStruct().isEmpty()) {
holder.viewFliperMelk.addSlider(new TextSliderView(mContext.getApplicationContext()).image(T.GET_MELK_IMAGE + '/' + sfi.getPicNamayeStruct() + ".jpg").setScaleType(BaseSliderView.ScaleType.CenterCrop));
}
}
I had a similar issue when getting pictures from the photo gallery and putting them in a recyclerview with GridLayoutManager(never had the issue with Glide). So in the adapter onBindViewHolder use a HashMap or SparseIntArray to put the current hashcode(this is the common thing that the recycled views have in common) and adapter position inside it. Then call your background task and then once it's done and before you set the image, check to see if the hashcode key - which will always have the current adapter position as the value - still has the same value (adapter position) as when you first called the background task.
(Global variable)
private SparseIntArray hashMap = new SparseIntArray();
onBindViewHolder(ViewHolder holder, int position){
holder.imageView.setImageResource(R.drawable.grey_square);
hashMap.put(holder.hashCode(), position);
yourBackgroundTask(ViewHolder holder, int position);
}
yourBackGroundTask(ViewHolder holder, int holderPosition){
do some stuff in the background.....
*if you want to stop to image from downloading / or in my case
fetching the image from MediaStore then do -
if(hashMap.get(holder.hashCode())!=(holderPos)){
return null;
}
- in the background task, before the call to get the
image
onPostExecute{
if(hashMap.get(holder.hashCode())==(holderPosition)){
holder.imageView.setImageBitmap(result);
}
}
}
So i am just providing an extension to this answer since there is not much space to leave it as comment.
After trying out like mentioned in one of above solutions i found out that, the real issue can still be addressed even if you are using a static resource(is not being downloaded and is available locally)
So basically on onBindViewHolder event i just converted the resource to drawable and added it like below :
imageView.setImageDrawable(ContextCompat.getDrawable(context,R.drawable.album_art_unknown));
this way you wont have an empty space on the view while glide/async downloader is loading the actual image from network.
plus looking at that being reloaded every time i also added below code while calling the recycler adapter class;
recyclerView.setItemViewCacheSize(10);
recyclerView.setDrawingCacheEnabled(true);
so by using above way you wont need to set setIsRecyclable(false) which is degrading if you have larger datasets.
By doing this i you will have a flicker free loading of recyclerview of course except for the initial loads.
I would like to say that if you send the ImageView and any load-async command (for instance loading from S3), the recycler view does get confused.
I did set the bitmap null in the onViewRecycled and tested with attach and detach views etc. the issue never went away.
The issue is that if a holderView gets used for image-1, image-10 and stops at the scroll with image-19, what the user sees is image-1, then image-10 and then image-19.
One method that worked for me is to keep a hash_map that helps know what is the latest image that needs to be displayed on that ImageView.
Remember, the holder is recycled, so the hash for that view is persistent.
1- Create this map for storing what image should be displayed,
public static HashMap<Integer, String> VIEW_SYNCHER = new HashMap<Integer, String>();
2- In your Adapter, onBindViewHolder,
String thumbnailCacheKey = "img-url";
GLOBALS.VIEW_SYNCHER.put(holder.thumbnailImage.hashCode(), thumbnailCacheKey);
3- Then you have some async call to make the network call and load the image in the view right ?
In that code after loading the image from S3, you test to make sure what goes into the View,
// The ImageView in the network data loader, get its hash.
int viewCode = iim.imView[0].hashCode();
if (GLOBALS.VIEW_SYNCHER.containsKey(viewCode))
if (GLOBALS.VIEW_SYNCHER.get(viewCode).equals(bitmapKey))
iim.imView[0].setImageBitmap(GLOBALS.BITMAP_CACHE.get(bitmapKey).bitmapData);
So essentially, you make sure what is the last image key that should go into a view, then when you download the image you check to make sure that's the last image URL that goes in that view.
This solution worked for me.
I'm trying to implement a basic GridView gallery as per the Android Developer Guide/Tutorial.
The ImageViews inside my grid are Bitmaps taken from a user's camera.
This works fine except for the fact that my images are incredibly small.
My xml:
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<GridView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/gridview"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:columnWidth="90dp"
android:numColumns="auto_fit"
android:verticalSpacing="10dp"
android:horizontalSpacing="10dp"
android:stretchMode="columnWidth"
android:gravity="center"
/>
</LinearLayout>
My ImageAdapter
public class ImageAdapter extends BaseAdapter {
private Context mContext;
private ArrayList<Bitmap> imgs;
public ImageAdapter(Context c, ArrayList<Bitmap> arrayList) {
mContext = c;
imgs = arrayList;
}
public int getCount() {
return imgs.size();
}
public Object getItem(int position) {
return null;
}
public long getItemId(int position) {
return 0;
}
// create a new ImageView for each item referenced by the Adapter
public View getView(int position, View convertView, ViewGroup parent) {
ImageView imageView;
if (convertView == null) {
// if it's not recycled, initialize some attributes
imageView = new ImageView(mContext);
imageView.setLayoutParams(new GridView.LayoutParams(85, 85));
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
imageView.setPadding(8, 8, 8, 8);
} else {
imageView = (ImageView) convertView;
}
imageView.setImageBitmap(imgs.get(position));
return imageView;
}
}
I've tried various things to fix this issue, but the only one that seems to work is adjusting the ImageView's layout params to enormous numbers (e.g. GridView.LayoutParams(300, 300)).
However, even if I do this, my images are still relatively small (i.e. nowhere near 300dp x 300dp).
Any idea what I'm doing wrong?
Put this param in your ImageView.
android:adjustViewBounds="true"
You can see this too.
How to find cell width from StaggeredGridLayoutManager?
Setting layout params in my adapter to GridView.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT)) managed to fix the issue.
Found this solution at GridView items are too small - Android
Try to change for bigger size:
android:columnWidth="90dp"
you should accept the answer of
android:adjustViewBounds="true"
What it means?it stretches your image to fit the height and width of your image view so they won't be small,but why you don't want to use
android:ScaleType="fitXY"?
Because first option adjusted the proportion of your image so it won't lose the quality and second one anyway stretches it and it loses quality!
IMPORTANT:be aware that if image will be too small,adjust option will not work as it must save the image proportion,so its all up to you what you want to use!
The problem is that new GridView.LayoutParams() expect args in pixels.
So, your need to convert 85 from dp to pixels first.
I've got the following code from "Android in Practice" book. It's implementation of custom adapter which downloads images from the internet. It uses private class RetrieveImageTask to retrieve pictures.
Can someone explain me why the first thing the adapter class does is to get image from the cache instead of downloading it ? I understand it in a way that, the first time it displays
default image which was set in the beginning of getView(), then sets downloaded image, but does it mean that view is being refreshed constantly by calling getView() ?
And why author sets tag of image to item ID in getView() and then sets it to null in onPostExecute() ?
DealsAdapter
private class DealsAdapter extends ArrayAdapter<Item> {
public DealsAdapter(List<Item> items) {
super(DealList.this, R.layout.list_item, items);
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null) {
LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.list_item, parent, false);
}
// use ViewHolder here to prevent multiple calls to findViewById (if you have a large collection)
TextView text = (TextView) convertView.findViewById(R.id.deal_title);
ImageView image = (ImageView) convertView.findViewById(R.id.deal_img);
image.setImageBitmap(BitmapFactory.decodeResource(getResources(), R.drawable.ddicon));
Item item = getItem(position);
if (item != null) {
text.setText(item.getTitle());
Bitmap bitmap = app.getImageCache().get(item.getItemId()); //<------HERE
if (bitmap != null) {
image.setImageBitmap(bitmap);
} else {
// put item ID on image as TAG for use in task
image.setTag(item.getItemId());
// separate thread/via task, for retrieving each image
// (note that this is brittle as is, should stop all threads in onPause)
new RetrieveImageTask(image).execute(item.getSmallPicUrl());
}
}
return convertView;
}
}
RetriveImageTask
private class RetrieveImageTask extends AsyncTask<String, Void, Bitmap> {
private ImageView imageView;
public RetrieveImageTask(ImageView imageView) {
this.imageView = imageView;
}
#Override
protected Bitmap doInBackground(String... args) {
Bitmap bitmap = app.retrieveBitmap(args[0]);
return bitmap;
}
#Override
protected void onPostExecute(Bitmap bitmap) {
if (bitmap != null) {
imageView.setImageBitmap(bitmap);
app.getImageCache().put((Long) imageView.getTag(), bitmap);
imageView.setTag(null);
}
}
}
Its called lazy loading. well images take time to download from net so by that some dummy image is set. As the downloading completes it will replaced with dummy image. Basically is matter of user experience with application.
the tag has something to do with how the cache mechanism of your code works- the key of the items is their number in this sample , meaning it is used to identify which image was downloaded so that you could load it from the cache instead of from the internet.
i agree that it's weird, as it could simply put the url of the image instead. using the url is more logical .
the sample isn't so efficient as it doesn't use the viewHolder design pattern (you can learn about it via the lecture "the world of listView") and doesn't have downsampling in mind (you can check out this post about it).
the image that is shown before showing the correct image is for showing the user that it's being prepared (like a placeholder saying "downloading...").
it's just a sample for you to learn from.
Blatant n00b question: I have several directories of pictures and wish to display randomly pictures from only one, which I select by a set of radio buttons. How do I specify the directory when using :
//"ha" is ha.png, which I would like to be at drawable/1/ha.png
image.setImageResource(R.drawable.ha);
Can I use setImageResource for this? If so how? If not, what should I use and how?
The object of the exercise is a flashcard program with different lessons (hence the dividing up of images) selectable at the first activity.
You cannot have subfolders under res/drawable, if you are referring to the drawables folder in your apk.
If you are referring to a random folder on your sdcard, then it's fine to use subfolders, but then you cannot use R.drawable.* for that approach to refer to the image.
In that case you need to load the image using
Bitmap bmp = BitmapFactory.decodeFile("/sdcard/drawable/1/ha.png");
which returns a bitmap, which you can use like
image.setImageBitmap(bmp)
see http://developer.android.com/reference/android/widget/ImageView.html#setImageBitmap(android.graphics.Bitmap)
In order to react on changes made to the radion button, see
How to set On click listener on the Radio Button in android
You can use a GridView to show the images from a directory selected from a radio button (as your requirement says). After creating a GridView, associate a adapter to it. Please refer below for a n example adapter :
public class ImageAdapter extends BaseAdapter {
/** LayoutInflater. */
private LayoutInflater mInflater;
/** The i. */
private ImageView i;
/**
* Instantiates a new image adapter.
*
* #param c
* the c
*/
public ImageAdapter(Context c) {
mInflater = LayoutInflater.from(c);
}
public int getCount() {
// scaled pictures will have the list of
// which you have from the directory
return scaledPictures.size();
}
public Bitmap getItem(int position) {
return scaledPictures.get(position);
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null) {
convertView = mInflater.inflate(R.layout.image, parent, false);
} else {
i = (ImageView) convertView;
}
Bitmap bitmap = getItem(position);
i = (ImageView) convertView.findViewById(R.id.galleryimage);
i.setImageBitmap(bitmap);
bitmap = null;
return i;
}
}
I'm following the example on the android tutorial about the GridView, but instead of showing image, i want to just simple show some text using a TextView. it turns out seems to be harder than i thought. it might seems like this is totally unnecessary and it doesn't have a valid use case, but i'm trying this out to just get myself familiar with the sdk.
so my code is pretty much the same as the GridView example in http://developer.android.com/guide/tutorials/views/hello-gridview.html, but instead of using a ImageAdapter, i created a dummy adapter like following:
public class MyAdapter extends BaseAdapter {
private Context context;
private String[] texts = {"aaa", "bbb", "ccc", "ddd", "eee", "fff", "eee", "hhh", "iii"};
public MyAdapter(Context context) {
this.context = context;
}
public int getCount() {
return 9;
}
public Object getItem(int position) {
return null;
}
public long getItemId(int position) {
return 0;
}
public View getView(int position, View convertView, ViewGroup parent) {
TextView tv;
if (convertView == null) {
tv = new TextView(context);
tv.setLayoutParams(new GridView.LayoutParams(85, 85));
}
else {
tv = (TextView) convertView;
}
tv.setText(texts[position]);
return tv;
}
}
it all seems valid to me, but running this gives me nothing on the screen. and there's no error message. there are some selectable/clickable (invisible) blocks if i click them, but the text is obvious not shown. i wonder is my layout doesn't have the android:text causing this problem? or anything else?
any feedback will be appreciated and thanks for your help!
I am not sure what could be causing your problem. I followed the step by step instructions on the page that you linked to to set up "Hello, GridView", and used your code and was able to see the text.
The only things I changed was rather than creating a class for ImageAdapter I used your MyAdapter. In the activity HelloGridView.java onCreate I used "MyAdapter" rather than "ImageAdapter". I didn't change the layout at all.
Here is a Screenshot of what I get when running your code.
I see GridView so I'm almost assuming that this is similar to SWT?
If so you need to show the relationship between your view and the ViewGroup parent
I don't think your getItem implementation is correct. Top of my head it should be
return texts[position];