Infinum Android Talks #17 - Developing an Android library by Dino Kovac

Infinum Android Talks #17 - Developing an Android library by Dino Kovac

• 1.
  Developing an Android library DINOKOVAČ
• 2.
  01WHY?
• 3.
  WHY A LIBRARY? •DRY - don’t repeat yourself • easier than copy/pasting classes
• 4.
  WHY AN OPENSOURCE LIBRARY? • saving others time • useful contributions from community • eternal fame!
• 5.
  02WHAT?
• 6.
  DOES IT MAKESSENSE TO BUILD IT? • is there a real need? • any existing libraries?
• 7.
  PICK A GOODNAME • one that doesn’t already exist • should make sense • bonus points if it’s amusing • example: • HTTParty - Makes http fun again!
• 8.
  03HOW?
• 9.
  MIND THE API •primary way users interact with your lib • make it easy to use • make it robust (avoid footguns!)
• 10.
  HTTPURLCONNECTION HttpURLConnection urlConnection =null;
 try {
 URL url = new URL("https://api.github.com/markdown/raw");
 connection = (HttpURLConnection) url.openConnection();
 connection.setDoOutput(true);
 connection.setChunkedStreamingMode(0);
 
 OutputStream out = new BufferedOutputStream(connection.getOutputStream());
 writeStream(out);
 
 InputStream in = new BufferedInputStream(connection.getInputStream());
 readStream(in);
 } catch (IOException e) {
 // handle this
 } finally {
 if (connection != null) {
 connection.disconnect();
 }
 }
• 11.
  HTTPURLCONNECTION
• 12.
  OKHTTP Request request =new Request.Builder()
 .url("https://api.github.com/markdown/raw")
 .post(RequestBody.create(MediaType.parse("text/plain"), "post body"))
 .build();
 
 try {
 Response response = client.newCall(request).execute();
 } catch (IOException e) {
 // handle this
 }
• 13.
  FAIL FAST • asmuch validation as reasonably possible • fail as fast as possible
• 14.
  FAIL FAST public Builderpost(RequestBody body) {
 return method("POST", body);
 }
 
 public Builder method(String method, RequestBody body) {
 if (method == null || method.length() == 0) {
 throw new IllegalArgumentException("method == null || method.length() == 0");
 }
 if (body != null && !HttpMethod.permitsRequestBody(method)) {
 throw new IllegalArgumentException("method " + method + " must not have a request body.");
 }
 if (body == null && HttpMethod.requiresRequestBody(method)) {
 throw new IllegalArgumentException("method " + method + " must have a request body.");
 }
 this.method = method;
 this.body = body;
 return this;
 }
• 15.
  DON’T EXPOSE THEINTERNALS • package-protected classes • private or protected methods
• 16.
  WRITE THE DOCS •what does it do? • how do I use it? • maybe an example app?
• 17.
  Any questions? DINO@INFINUM.CO @DINO_BLACKSMITH Visit infinum.coor find us on social networks: infinum.co infinumco infinumco infinum