Using xml and json with android, part 1_ explore the benefits of json and xml in android applications

The value of XML’s self-describing nature is clear when you contrast it to the state of the art before XML’s general adoption. Find my android phone Then, data-interchange exercises included laborious data-description documents, often written and maintained by hand in a word processor or spreadsheet application. Android phone encryption These documents, commonly known as interface specifications, depicted field names, lengths, delimiters, hierarchies, and so on. Top 3 android phone Users followed practices as they saw fit; the closest thing to a standard was the familiar comma-separated-value (CSV) format.


Android phone help Even CSV files vary a good deal. Android jelly bean phone If you doubt it, try to import one into a spreadsheet program and notice all of the options available.An XML document has a recognizable structure: a series of elements that can optionally contain attributes and child elements. Best android phone review Every valid XML document begins with a declaration on the first line: . Android phone under 3000 What comes after the first line is application-dependent. Android phone manager for pc The beauty of XML is that it is self-describing. Android apps windows phone XML schemas
Although XML documents are self-describing, they must follow certain rules and guidelines. 1 android phone This is where the XML schema comes in. Com android phone has stopped unexpectedly It is a document that describes the structure of a particular XML file. Unfortunately the process com android phone has stopped Such structures are often verbose and complex. Android phone ratings (Arguably, XML’s worst contribution to the IT field is the data explosion that took place once the idea of highly descriptive data structures came into fashion, fueled in part by the greatly reduced cost of disk-storage technology in the past decade.)
As these large and complex files became more the norm, the art of working on them manually was often a nonstarter for programmers and analysts. Com android phone To address this issue, XML editors and validating tools became available to aid in the management of the files and the tasks relating to them, such as documentation and conversion to legacy formats.
In addition to general text data, XML can also be used to store binary data through a special set of tags known as CDATA. Android phone 32gb internal memory CDATA tags within an XML document can contain any kind of data, including other mark-up text, provided that text does not contain CDATA itself.
It’s not uncommon for APIs to leverage this capability by using XML as a structure for performing request/response queries. 3 android phones Often the response data contains an XML structure contained within a CDATA tag. Android phone apps free For example, an API call might request a customer record with a last name equaling Mott. Android phone with best camera When the data is found, it is packaged into an XML structure and placed within the response element, as in Listing 1: Listing 1. Android dev phone Packaging data into an XML structure and placing it within the response element
XML is self-describing, but that doesn’t mean that the tags are necessarily easy to decipher. Android phone emulator online This cryptic example also demonstrates the use of multiple XML namespaces, which can make XML documents even more challenging to follow without specialized tools.
XML is everywhere, but it can often be a poor choice for an Android programmer, particularly if the data structure has fallen victim to the data explosion often associated with XML structures. Best android phone 2014 A resource-constrained platform such as Android, which is usually working on a cellular data network, cannot store and parse massive amounts of XML data. Android phone call apps However, if a particular programming task requires the interchange of both text and binary data, XML can be a solid choice.

Whereas XML is known for its verbosity, JSON has a reputation for being somewhat hard to read. Com android phone huawei JSON objects are constructed in a key: value pair format. Android phone google The object’s elements are separated by commas, and each object is contained within curly braces {}. Best 4 android phone An array of objects is contained within square brackets. Android phone recommendations This is a common approach to transferring a series of rows from a database to an array of objects in which each array element corresponds to a database row, and each property of the object represents a column of data.
Listing 3 shows an example of using this kind of object within an HTML page. Android phone virus symptoms For simplicity, the server communications are not included; instead, the JSON data is provided as a string variable named serverresponse. Android phone features Listing 3. Android phone not connecting to pc Using a JSON object within an HTML page
Android also supports a DOM parser, which requires a larger memory footprint but reduces some of the complexity found in the SAX parser. Proces com android phone zostal zatrzymany For an application such as XMLvsJSON, which is only interested in a very small subset of a large data feed, the SAX approach is likely the better tool for the job.
Parsing of XML data is often done with a SAX-style parser. Best android phone today With this style of parser, you set up an InputSource pointing to the source XML data and provide a handler that receives certain events as the document is “walked.” Listing 8 shows the examineXMLFile() method, which takes care of the following tasks:

Listing 9 contains some noteworthy items. Android phone of samsung The first thing to consider is that the SAX parser is an event-based parser, which means that you build the actual document as it is parsed. Mt65xx android phone driver xp download Events are fired whenever the document starts, the document ends, a tag starts, a tag ends, and data is found. Android phone emoticons This implies that you must define a data structure to keep the data of interest and discard the rest.
Note the StringBuilder and the appending of data, used because a particular data element can be processed across multiple reads on the InputSource. Android phone keeps turning off Never assume that all of the data is provided in any given call to the characters() method.
This application collects the data into a simply formatted string. What android phone to get An alternative example might include putting these entries into a collection class or database instead, particularly if a great deal of manipulation were to take place after the parse.
The getResults() method is custom to this class. Lenovo android phone reviews It’s used to gather the assembled representation of this data and provide it to the application. 0 android phone It is not part of the DefaultHandler’s interface.
Although parsing XML with the SAX parser is nontrivial in terms of building up, managing, and navigating the resulting structure, its main advantages are speed and the opportunity to reduce significantly the amount of RAM required both during and after the parsing step.

Like the XML routine shown previously, this code reads in a file from the raw resources. Android phone deals The data is read into memory in its entirety, converted to a java.lang.String, and then parsed into a JSONArray. Lge android phone driver xp Note that a particular string can be parsed directly into an array, as in this example, or the string can be parsed into a JSONObject. Android phone 10000 Because the Twitter data is an array of objects, it makes sense to parse the entire string into an array and then access the object individually by ordinal position.
string representation that’s similar to the approach of the XML parser handler. What android phone should i buy Of interest here is that the data is managed for you; you don’t need to build up additional memory structures to contain the data. Android for phone Likewise, the application knows up front just how many entries are in the JSONArray (20 in this example).
Although JSON parsing is much more simple programmatically, it is not cost-free. Android phone update apps It adds the burden of memory consumption for reading in the entire data stream before it can be worked on, and for storing all of the data. Phone android marshmallow In contrast, the SAX XML approach uses only the data of interest. Android phone how to That caveat aside, if memory for parsing a particular JSON object is ample, this approach can be favorable for many applications, particularly if working with the DOM is of little interest.

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