add network methods

DailyHelper/app/src/main/java/at/fhj/swd/dailyhelper/network/HttpsClient.java

@@ -0,0 +1,118 @@
+package at.fhj.swd.dailyhelper.network;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.OutputStream;
+import java.io.OutputStreamWriter;
+import java.net.URL;
+
+import javax.net.ssl.HttpsURLConnection;
+
+
+/**
+ * General workflow for connections with UrlConnection:
+ *
+ * The connection object is created by invoking the openConnection method on a URL.
+ * The setup parameters and general request properties are manipulated.
+ * The actual connection to the remote object is made, using the connect method.
+ * The remote object becomes available. The header fields and the contents of the remote object can be accessed.
+ *
+ */
+public class HttpsClient {
+    public String get(URL url) throws IOException {
+        InputStream stream = null;
+        HttpsURLConnection connection = null;
+        String result = null;
+        try {
+            connection = (HttpsURLConnection) url.openConnection();
+            connection.setReadTimeout(3000);
+            connection.setConnectTimeout(3000);
+
+            //this is a get request
+            connection.setRequestMethod("GET");
+            //indicate that this connection wants to read from the connection
+            connection.setDoInput(true);
+
+            //connect and therefore initiate network communication
+            connection.connect();
+
+            int responseCode = connection.getResponseCode();
+            if (responseCode != HttpsURLConnection.HTTP_OK) {
+                throw new IOException("HTTP error code: " + responseCode);
+            }
+            stream = connection.getInputStream();
+
+            if(stream != null) {
+                BufferedReader r = new BufferedReader(new InputStreamReader(stream));
+                StringBuilder total = new StringBuilder();
+                for (String line; (line = r.readLine()) != null; ) {
+                    total.append(line).append('\n');
+                }
+                result = total.toString();
+            }
+        } finally {
+            if (stream != null) {
+                stream.close();
+            }
+            if (connection != null) {
+                connection.disconnect();
+            }
+        }
+        return result;
+    }
+
+    public String post(URL url, String body) throws IOException {
+        InputStream stream = null;
+        HttpsURLConnection connection = null;
+        String result = null;
+        try {
+            connection = (HttpsURLConnection) url.openConnection();
+            connection.setReadTimeout(3000);
+            connection.setConnectTimeout(3000);
+
+            //this is a post request
+            connection.setRequestMethod("POST");
+            //indicate that this connection wants to read from the connection
+            connection.setDoOutput(true);
+
+            //write request body to connection object
+            OutputStream outputStream = connection.getOutputStream();
+            OutputStreamWriter outputStreamWriter = new OutputStreamWriter(outputStream, "UTF-8");
+            outputStreamWriter.write(body);
+            outputStreamWriter.flush();
+            outputStreamWriter.close();
+            outputStream.close();
+
+            //connect and therefore initiate network communication
+            connection.connect();
+
+            int responseCode = connection.getResponseCode();
+            if (responseCode != HttpsURLConnection.HTTP_OK) {
+                throw new IOException("HTTP error code: " + responseCode);
+            }
+
+            stream = connection.getInputStream();
+
+            if(stream != null) {
+                BufferedReader r = new BufferedReader(new InputStreamReader(stream));
+                StringBuilder total = new StringBuilder();
+                for (String line; (line = r.readLine()) != null; ) {
+                    total.append(line).append('\n');
+                }
+                result = total.toString();
+            }
+
+        } finally {
+            if (stream != null) {
+                stream.close();
+            }
+            if (connection != null) {
+                connection.disconnect();
+            }
+        }
+        return result;
+    }
+}
+

DailyHelper/app/src/main/java/at/fhj/swd/dailyhelper/network/HttpsGetTask.java

@@ -0,0 +1,61 @@
+package at.fhj.swd.dailyhelper.network;
+
+import android.os.AsyncTask;
+import android.util.Log;
+
+import java.io.IOException;
+import java.net.URL;
+
+//Async task has 3 generic types for:
+//Params
+//Progress
+//Result
+public class HttpsGetTask extends AsyncTask<String, Void, String> {
+    private static final String TAG = "HttpsGetTask";
+    private RequestCallback callback;
+
+    public HttpsGetTask(RequestCallback callback) {
+        this.callback = callback;
+    }
+
+    //Do preparation here
+    //this is executed on UI thread, so no network communication here!
+    @Override
+    protected void onPreExecute() {
+        Log.d(TAG, "Preparing ...");
+        if(callback != null) {
+            callback.onRequestStart();
+        }
+    }
+
+    //this runs in background
+    //will be called after onPreExecute
+    @Override
+    protected String doInBackground(String... params) {
+        Log.d(TAG, "Doing background work ...");
+        HttpsClient httpsClient = new HttpsClient();
+        String result = null;
+        try {
+            result = httpsClient.get(new URL(params[0]));
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        return result;
+    }
+
+    //will be called after doInBackground
+    //runs on UI thread
+    //gets the result of doInBackground as its parameter
+    @Override
+    protected void onPostExecute(String result) {
+        if(callback != null)
+            callback.onResult(result);
+    }
+
+    //will be called if publishProgress is called during doInBackground
+    //runs on UI thread
+    @Override
+    protected void onProgressUpdate(Void... values) {
+    }
+}
+

DailyHelper/app/src/main/java/at/fhj/swd/dailyhelper/network/RequestCallback.java

@@ -0,0 +1,6 @@
+package at.fhj.swd.dailyhelper.network;
+
+public interface RequestCallback {
+    void onRequestStart();
+    void onResult(String result);
+}