simple android application to read data from json file

Here’s the design I chose:Ĭustom ListView Adapter Layout – adapter_log.xml I called mine adapter_log.xml since its an adapter and its for the log file. Create an “adapter” that defines how incoming data maps to your design from step 1Ĭreate a new xml file.Design a single row item with an layout XML file.The technique for creating a custom ListView is fairly simple but can be intimidating. Lastly we need to design and create the custom ListView template we want to use.

The Layout for the ListView – activity_log.xml I called mine “activity_log.xml” It only needs an empty ListView. Create a new Android Activity for the log viewer. Next we’ll need an activity to view the JSON log as a listview. I’ll show the “clickListener” function in MainActivity.java I prefer to use the technique for handling button clicks. Note the onClick function called “clickListener”. Layouts The Home Screen Layout – activity_main.xml As a bonus – a menu option will be created to clear all entries in the log file.Īs you can see we’ve got a lot to do so let’s get started.

When “View Log” is clicked a new activity starts that shows a custom ListView that has a row for each entry in the JSON file.

When “Create Entry” is clicked a JSON object containing the current date, time, and description is created and stored in a JSON file which is stored locally on the device.

Home screen has two buttons, called “Create Entry” and “View Log”.

To do this you can use GSON library (I dunno if standard Android packages have this functionality) and you should get something like this:Īnd to parse it you simply use val transport = Gson().fromJson(stringVariable, Transport::class.java)Īnd can use it like transport.In this tutorial we will create a simple Android app that applies the following techniques:ĭownload the source code for this project here. Val jsonFileAsString = stringBuilder.toString()Ģ.Secondly, you have to create a JSONOBJECT from the previous result ( the jsonFileAsString variable) val jsonObject = JSONObject(jsonFileAsString)įinally, to read a specific property you can useīut to make things clear you should consider making a data class to match specific JSON file and parse it that way.

Val bufferedReader = BufferedReader(fileReader) Val fileReader = FileReader(File(context?.filesDir, FILE_NAME))

Firstly, you have to read the file and assign the content to some string variable val file = File(context?.filesDir, FILE_NAME)

Simple android application to read data from json file