I m using Fedor's lazy Loader Adapter for showing images on a list view.
I want to pass the image(already downloaded) of the row which is clicked to new activity. I dont want to re download the image again.
How can this be done ?
Ref : Lazy load of images in ListView
Fedor's Code (from what i've read) uses a File Cache aswell as a Memory Cache to Cache the downloaded files...
So Simply use
FileCache fileCache = new FileCache(context);
File bmp = fileCache.getFile(url);
//convert the File object to a Bitmap object using BitmapFactory (see decodeFile() method in ImageLoader)
and
MemoryCache memCache = new MemoryCache(context);
Bitmap bmp = memCache.get(url)
Note : If both return null, then you'll have to download it again.
Related
We have an image in B64, an we want to use that image as loading image in Universal Image Loader while a better image isn't loaded from an url. So we create a bitmap from that url in b64 and convert it into a BitmapDrawable.
The result is shown fine if I do:
imageView.setImageDrawable(bitmapDrawable)
But, on DisplayImageOptions, if I set that bitmapDrawable as image on loading, the image is never shown. I'm doing the following:
final DisplayImageOptions imageOptions = mDisplayImageOptionsDefaultBuilder.
.showImageOnLoading(bitmapDrawable)
.showImageOnFail(bitmapDrawable)
.showImageForEmptyUri(bitmapDrawable)
.build()
As you can see, I am setting the bitmap drawable not only as image when loading, but as image when fails too (as we don't want that image to change in case of error while loading the better image from an url). The result of that is that the bitmap drawable is never shown. What are we doing wrong?
UPDATE:
After debugging what was happening I've seen that the problem is not the bitmap drawable, it is supported and working fine. The problem was that I am using a default display options builder (mDisplayImageOptionsDefaultBuilder), than at some point did:
final DisplayImageOptions imageOptions = mDisplayImageOptionsDefaultBuilder.
.showImageOnLoading(loadingResource)
.showImageOnFail(errorResource)
.showImageForEmptyUri(errorResource)
.build()
So there's a bug in Universal Image Loader, because now I'm creating a display image options with:
.showImageOnLoading(bitmapDrawable)
Another "solution" is do:
final DisplayImageOptions imageOptions = mDisplayImageOptionsDefaultBuilder.
.showImageOnLoading(0)
.showImageOnLoading(loadingResource)
.showImageOnFail(errorResource)
.showImageForEmptyUri(errorResource)
.build()
But internally it stores that there's a resource stored, so my drawable is not shown but the stored resource instead. Creating a new DisplayImageOptionsBuilder worked for me, but it would be nice that if the showImageOnLoading is set with a drawable, then the old resource was automatically cleared.
Thanks in advance.
UIL only supports the following schemes:
"h t t p://site.com/image.png" // from Web
"file:///mnt/sdcard/image.png" // from SD card
"file:///mnt/sdcard/video.mp4" // from SD card (video thumbnail)
"content://media/external/images/media/13" // from content provider
"content://media/external/video/media/13" // from content provider (video thumbnail)
"assets://image.png" // from assets
"drawable://" + R.drawable.img // from drawables (non-9patch images)
Use these schemes.
Universal Image Loader also provide to use the Background functionality.Please check the below coed for it:-
Here Uri is the path of the folder image OR the URL of the image.
imageLoader.loadImage(YOUR_URL, new SimpleImageLoadingListener() {
#Override
public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) {
super.onLoadingComplete(imageUri, view, loadedImage);
layout.setBackgroundDrawable(new BitmapDrawable(loadedImage));
}
});
I'd like to load image which is on SDCARD in folder to imageView of my cell in listView. I've tried different solutions but each of them fails. When I load images normally as it is in every base tutorial everything works. I've observed that, my application slows down when it has to load many images. Images are taken from photo camera of device. I'd like to load each of them asynchronously to avoid UI slow reaction. I've tried to use Thread, Asynctask but each of them throws error: "Only the oryginal thread that created a view hierarchy can touch its views". How to load images to avoid speed problems? SDImageLoader is a class which is possible to get from GITHUB. What I've tried is a standard code but is slows:
In a getView method in ListAdapter:
File imageFile = new File(Options.PATH_TO_FOLDER_PHOTOS_OF_APP + "test.png");
String imageFileString = Options.PATH_TO_FOLDER_PHOTOS_OF_APP + "test.png";
// "test.png" is a test file. Each cell will have different name of file to load.
if(imageFile.exists())
{
Bitmap myBitmap = BitmapFactory.decodeFile(imageFile.getAbsolutePath());
image.setImageBitmap(myBitmap);
// final SDImageLoader loader = new SDImageLoader(context);
// new SDImageLoader().load(imageFileString, image);
//UrlImageViewHelper.setUrlDrawable(image, url);
}
else
{
final SDImageLoader loader = new SDImageLoader();
Resources resources = context.getResources();
int resurceId;
resurceId = resources.getIdentifier("bad", "drawable",context.getPackageName());
loader.load(imageFileString, image);
image.setImageResource(resurceId);
}
Have you tried to refresh your project after adding an external library to your project? It doesn't matter with the fragment. You send exact context to the List Adapter - which should be fragment.this.getActivity().
Universal Image Loader provide many ways to load the image.
"file:///mnt/sdcard/image.png" // from SD card
"file:///mnt/sdcard/video.mp4" // from SD card (video thumbnail)
"content://media/external/images/media/13" // from content provider
"content://media/external/video/media/13" // from content provider (video thumbnail)
"assets://image.png" // from assets
"drawable://" + R.drawable.img // from drawables (non-9patch images)
But all these way load image form file, I need a way to load from memory since my images was encrypted and stored in the assets folder, When I display this image, I need the following steps.
decrypt the image into bytes array.
Create bitmap from the bytes.
Load/display the image.
So it's something like this. Is that possible?
Bitmap bitmap = decrypt(encryptedImageFile);
imageLoader.displayImage(bitmap, imageView);
Currently, I am considering to save the bitmap to file and load the file, but this will take more time.
I believe the below is what you are seeking if your images are stored in image folder in assets directory, then you can get the list of images
private List<String> getImage(Context conetx) throws IOException {
AssetManager assetManager =conetx.getAssets();
String[] files = assetManager.list("image");
List<String> it=Arrays.asList(files);
return it;
}
As a note, instead of using assets dir, put the file into /res/raw and you can then access it using the following URI
android.resource://com.your.packagename/" + R.raw.<nameoffile>
I think you need to understand this. You must know, If you have read the source code of universal-image-loader, the order of loading a image into a ImageView after the image's url is provided, is: memory, SDCard(if set), internet. That means after you called, ImageLoader.display(url, imageview);, it will look for the Bitmap from memory first, if it doesn't exist, if will look for the file of the image from SDCard then, if the file exist, if will convert the file into a Bitmap, then load the Bitmap into the ImageView and store it in memory. But if the file doesn't exist, it will download the image file of the url, then store the file into the SDCard and convert the file into a Bitmap and load the Bitmap into memory. Most importantly, I recommend you to read source codes of it, if you are confused with what I post above.
So, it is unnecessary for you to load the Bitmap from memory, ImageLoader will do it for you.
Lets choose own scheme so our URIs will look like "stream://...".
Then implement ImageDownloader. We should catch URIs with our scheme and return image stream.
public class StreamImageDownloader extends BaseImageDownloader {
private static final String SCHEME_STREAM = "stream";
private static final String STREAM_URI_PREFIX = SCHEME_STREAM + "://";
public StreamImageDownloader(Context context) {
super(context);
}
#Override
protected InputStream getStreamFromOtherSource(String imageUri, Object extra) throws IOException {
if (imageUri.startsWith(STREAM_URI_PREFIX)) {
return (InputStream) extra;
} else {
return super.getStreamFromOtherSource(imageUri, extra);
}
}
}
DisplayImageOptions defaultOptions = new DisplayImageOptions.Builder()
.build();
ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(getApplicationContext())
.defaultDisplayImageOptions(defaultOptions)
.imageDownloader(new StreamImageDownloader(getApplicationContext()))
.build();
ImageLoader.getInstance().init(config);
ByteArrayInputStream stream = new ByteArrayInputStream(imgBytes);
String imageId = "stream://" + stream.hashCode();
DisplayImageOptions options = new DisplayImageOptions.Builder()
.extraForDownloader(stream)
.build();
ImageLoader.getInstance().displayImage(imageId, imageView, options);
I'm a little bit confused about the caching procedure when the images are stored into a custom ArrayAdapter....
As far as I know you can use LruCache only on Activities, so how to cache images in an adapter?
A Cache is just a data structure that keeps track of Objects. You can create your own cache, then save, for example, bitmaps using URLs as keys. For example, take this Object:
public static Map<String, Object> cache = new HashMap<String, Object>();
This is your cache. You can now save images by their urls. For example, say you get a bitmap from http://www.example.com/img.png. A simple method like this will get the cached image if it exists, or get a new one if it does not:
public Bitmap getImage(String url)
{
synchronized(cache) {
Object o = cache.get(url);
if (o != null)
return (Bitmap) o;
//here, get the bitmap from the URL using whatever method you want, then save it and return it:
Bitmap bmp = getBitmapForURL(url);
cache.put(url, bmp);
return bmp;
}
}
So you just call:
myImageView.setImageBitmap(getImage("http://www.example.com/img.png"));
Store only image URIs in adapter not the images.
In my application I have a grid view of images and when a user clicks an image then it will open the image in fullscreen. The images are loaded from the SD card as follows:
File sdDir = new File("mnt/sdcard/Pictures");
File[] sdDirFiles = sdDir.listFiles();
for(File singleFile : sdDirFiles) {
String filePath = singleFile.getAbsolutePath();
Bitmap bmp = scaleBitmap(filePath);
photos.add(bmp);
}
mThumbIds = photos.toArray(new Bitmap[(photos.size())]);
}
Scale bitmap is a method which decodes each file into a bitmap and then scales the bitmap before returning it.
I then have another Activity which loads the images fullscreen once they have been clicked. I have a menu button "Delete", from which I would like to delete the file on the sdcard which represents the bitmap I see on the screen.
The problem I have is that there is no way to get the file name from the Bitmap object, so therefore I cannot delete the file.
Any help will be greatly appreciated.
You could extend the Bitmap class and add a filename field. Or, you could pass the filename to your new activity in the intent bundle.