Students will become familiar with Async Task and begin to use REST APIs in their Android applications.
Create an app. The main activity should have a ListView and a button that says "Reload."
The UI thread is the thread that controls the interface - it makes updates to what is displayed to the user. There are other threads that are running concurrently, that is, the device switches between doing many things at once, and programs aren't necessarily linear.
AsyncTask allows you to perform background operations - operations that should not be on the UI thread - and publish these operations to the UI thread when they are done.
A few APIs you need to know for AsyncTask:
doInBackground -
The main method you override to execute a task in the background.
onPostExecute - The
method that gets called on the UI thread using the result from doInBackground.
onCancelled - The method
that gets called when the task is cancelled. If this is called, then onPostExecute won't be called.
REST stands for "Representational State Transfer." REST APIs are defined by their statelessness - the requests do not have memory. The main requests are the HTTP requests PUT, GET, POST and DELETE. We'll be working with GET requests, which specify their parameters in the URL.
API Keys - This is a parameter you pass that identifies you. It is used to log what requests you make and limit access.
Pagination - This is a feature that means you'll only get a certain number of requests at a time - for example, only the lastest 10 updates at a time.
Use the Flickr API to create a Flickr Feed app.
Use https://api.flickr.com/services/feeds/photos_public.gne?format=json to grab the latest 20 images uploaded to Flickr. When you click the "Reload" button, populate the view with the images.
Update the images periodically - e.g. once every 5 seconds. The number of seconds should be specified by the user. Include stop and start buttons.