I have json with some objects in it. And only one object from json i need. So which approach will be better for speed and performance - parse only this object or parse whole document instead?
If you want to show only the particular JSON Object which may be either inside a JSON Object or JSON array itself then you just parse that particular JSON Object instead of parsing whole document.
If you are not going to use rest of the data, you can just parse the item you only need.
In theory, just the object would get you a result faster with lesser work times. So just parse the object you need.
Related
I have a problem. I am parsing a JSON file from a website, and want to go through it using a for loop and display the content each JSON object contains. Each JSON object should correspond to one for loop cycle, and it should contain a header where a title and some information get displayed, and a ListView with more information about the JSON object. How would I do that the best way ?
The amount of JSON object is unknown and changes, so I assume all the views have to be created programmatically using a for loop.
It should look somewhat like this.
I'm not going to code that for you, but basically you could do the following:
Download JSON data with an AsyncTask
Parse JSON (you could GSON or Jackson) into a List<>
Use an ArrayAdapter or crate your own list adapter
Add the adapter to a ListView
Done
How to serialize/deserialize object in android with list of other objects inside ? I done this with sqlite to manually save all fields and in another table objects from list but I am curious is there any easier method.
A fairly easy way to serialize/deserialize an object would be to use JSON and a wrapper like Google Gson that will take care of all the hard work for you.
You haven't mentioned the purpose of serializing/deserializing these nested objects, but Gson will give you a nice little (json parseable) text file to do with as you please.
I receive from a web service a list of json objects that may containing different keys. Eg one would have a title, a url and a list of picture urls, another one would have the same more a phone number... I need to keep these objects in memory but I'm not sure about the best way to do it.
1- I could keep the JSONObject as it is.
2- I could create an array of generic Item object with all the possible fields (most are common to all items) and for each instance set only the fields which have the corresponding keys in the json object, and leave the others null.
3- I could also create for each object a map with the keys contained by the item.
Any thoughts about the best method?
Thanks
Jul
I would look at Jackson or GSON for JSON object mapping.
How can I serialize an ArrayList and Save it in a file?
The first thing you need to do is to serialize the class, the objects of which populate the ArrayList. If this is a simple class, composed mainly of primitive types and doesn't have a deep structure, this will be easy. You can choose JSON, protocol buffers or even XML for the representation. If you succeed on this, it will be straightforward to serialize the ArrayList.
I have been searching for a way to get the json data from a URl (for example: http://search.twitter.com/trends.json) and display it in a listview. Couldnt get a perfect example to get it done. Can anyone plz help me out by getting the solution and providing a good example of how to do it...
found this tutorial : http://damonsk.com/2010/01/jsonarray-httpclient-android/
Android comes with Json-lib so parsing JSON is easy. You just need to use the HTTPclient classes to retrieve the data from the URL, and you can use the JSONObject class to parse the JSON. And write a ListAdapter to pull data from the JSONObject.