I have to build some data from a json call and populate an object in Android mobile dev.
The json requires the read of the first url to get a list of data. One of the fields is an url to an image which I need to make a second call to the web using asyncTask to retrieve as a blob and save in the object.
I have the code working to get the first url call using the asyncTask. But as I process each set of data I need to make the second asyncTask call to get the image blob.
Is this possible or maybe I am going about it wrong? Sorry no code snippets.
It is not that tough as you are thinking.Follow the below example to parse image and data from json and display them:
http://www.androidbegin.com/tutorial/android-json-parse-images-and-texts-tutorial/
Create a separate package and copy the ImageLoader.java ,MemoryCache.java ,FileCache.java Utils.java
Then you can set your image within the adapter using the image url as:
ImageLoader imageLoader= new ImageLoader(context);
imageLoader.DisplayImage("the image url", imageview);
You can then reuse the imageloader class again and again throughout your project.
Apart from this you can also use third party apis to download images.
Some of them are Picasso and Glide
Currently I am using Glide.It is very powerful and easy to implement.
As per my understanding you want to display those images or download those images received in first asyncTask. I would suggest you for both purposes to use a library like picaso or fresco.
Over thinking it. I can make 2 http request under same task. Problem solved.
Related
Hello everyone i using this Lazylist , i need this lazy read all image in one path.
example :
i have this path http://www.example.com/image
in this path There are many image
http://www.example.com/image/image1.jpg
http://www.example.com/image/sacimge.jpg
http://www.example.com/image/xxx.jpg
and so on ...
need Lazy read all image in this path and insert in My Listview why How do I do that ???
Unfortunately I don't think this is possible. There is no way for lazyList to know how many images you have and what are their url. I suggest you create webservice
like
http://www.example.com/image/cat
Returning a json or xml array containing all the urls of you images.
On server side you can access your image directory and build this list dynnamicaly.
Then in your app you can call this webservice using (retrofit lib to make it easy for you). Then you can feed this url list into your LazyList.
I am using an ArrayAdapter along with ListView to display some images (I use Picasso to help with image handling). The images are initially loaded from the state on the local device. The adapter has ids for the images, which the getView() method of the adapter uses to get the path. If the image is not available locally, the local state returns an URL for the image. If the URL has expired, I need to fetch this from the backend.
If the URL is not expired, I have no issues, as I can either directly provide the path to Picasso or the URL and Picasso will handle everything for me. However, when I need to fetch the URL from the backend, I need to do this asynchronously. After fetching the URL, I tried doing the following but it doesn't seem to work (my getView() will in this case use Picasso with the URL):
adapter.remove(id);
adapter.add(id);
notifyDataSetChanged() doesn't seem to do much as well.
What is the best way to handle this situation? Is there any other way than what I am trying to do with the adapters? I want to delay the URL fetch from the backend as much as possible, basically until the user needs to see the image.
UPDATE: for now, I am replacing the id with a temp_id when the URL is expired and then add the correct id again, when I have the valid URL so that the view gets refreshed.
Have you tried clearing your ArrayList of image urls with myArray.clear()? Not so sure if I get your question or how your code looks like.
But I have issues like this before. What worked for me was to repopulating the adapter completely.
This link should help.
I am facing a problem with onItemClickListener. I have a ListView which contains strings as well as two images from parse.com table. I want to show the strings and images (that i have pushed in parse.com database) in another activity after I click on any item. I successfully get all the strings using getIntent() but I'm not able to find the solution to fetch the images from ListView item dynamically.
What is the best way to acomplish this?
In this case, the click event can provide the file Url's string value to another activity via the putExtra
look at the docs for calling $FileObj.'getUrl' that retrieves url as Type string
working with images in persistence you should store both full-sz and thumb-sz, working with the thumb in list-adapter context.
So, if u have store the bitmap for the thumbs file on parse, with "getUrl" you can operate on the URL value of the file( its useful in frameworks like 'Volley')
Read up on using adapters particularly "getView" to load the bitmap whenever you need to provide the bmp to a list adapter from your image lib.
Pass the File-Url-string to new activity in "Extra String Value"
Use Volley for your networking/file retreival and bitmap caching. bit of a guess but Volley and parse should be OK.
I am stuck up at one point. I need suggestions for the same.
I am creating an application which involves json parsing. After the parsing I am getting data which involves event name, event description, event place, event image url and so on. The data is huge. You can imagine facebook kinda stuff.
Now the problem is the data is getting parsed but because the event image is in the form of url, I need to convert it into Bitmap.
I have kept all the process of json parsing and bitmap conversion into one AsyncTask(doInBackground()).
This is taking a lot amount of time. I want something like facebook that the data gets loaded and is shown to the end user but the images load slowly and steadily. (I mean when we scroll facebook, then images don't come up immediately).
I want a similar functionality. I need suggestions.
You can still use an AsyncTask, only you'll need to use two seperate tasks.
One for the loading and parsing of the JSON, and one for the loading of the image.
After parsing the JSON, you'll need to start an AsyncTask for every image you're trying to load, making them all load on their own thread. It will show once the item is done loading.
Here is solution for you https://github.com/nostra13/Android-Universal-Image-Loader
You just pass url and imageview resource to loader, and it handles everithing for you. Also support caching. This library is simple and widly used
This concept is called Lazy Loading (AFAIK). You can use already development ImageLoader for this. It will download Image in Background and once it download it will set as background of ImageView. See Custom Downloader
In my application, when user presses Sync button (calls function onSynchronize()), I need to do the following activities:
form url for data synchronization based on user's preferences
download url
parse data received
for each item found in data download picture (another url)
update ListView with data downloaded and parsed
What is the best approach to split this activity between classes? Since steps 2-4 should be done in background (ASyncTask), and the same steps 1-4 will be used in the service (for automatic synchronization).
Should I put step 5 in onPostExecute of according ASyncTask? Or, should I put there steps 3-5? What is the most logical and clear approach?
First, you need an Adapter class for your ListView. Also you'll need a parser class(you can implement SAX or DOM if response is XML). Take a look at Lazy load of images in ListView to understand image downloading into ListView.
Your parser class can return an array of custom objects and then you'll supply it to listview via your custom adapter class.