Dweet.IO Android Java抽象类无法实例化

Question

我正在使用开放源代码库连接到Android应用程序上的Dweet.io，但遇到了一些麻烦。在我的主要活动中，我尝试设置DweetIO.listen方法，该方法应在其中使用DweetListener。我收到以下错误，“DweetListener是抽象的，不能被实例化”我不知道我要去的地方错了，因为所有的例子说明了如何我已经做到了。您可以在以下Github上找到原始库：https://github.com/kbakhit/java-dweetio

想知道是否有人有任何想法，让听者的工作？我附上下面的所有代码。

MainActivitiy.Java

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy);
        test();

    }

    public void test() {
        try {
            String thingName= "java-client-thing";

            JsonObject json= new JsonObject();
            json.addProperty("hello", "test!");
            DweetIO.publish(thingName, json);

            DweetIO.listen(thingName, new DweetListener(), null);
           // Dweet dweet= DweetIO.getLatestDweet(thingName);
          // Log.d("debug",dweet.getThingName()+ " said : "+ dweet.getContent().get("hello").getAsString() +" at "+ dweet.getCreationDate());
           List<Dweet> dweets= DweetIO.getAllDweets(thingName);
           for(Dweet d: dweets) {
               Log.d("debug2",d.getThingName() + " said : " + d.getContent() + " at " + d.getCreationDate());
           }

        }
        catch (ParseException e) {

        }
        catch (IOException e) {

        }

    }
}

DweetListener.java

public interface DweetListener
{
    public void dweetReceived(Dweet dweet);
    public void stopListening(String thingName);
    public boolean isStillListeningTo(String thingName);
    public void stoppedListening(String thingName);
    public void connectionLost(String thingName, Exception e);
}

DweetIO.Java

public class DweetIO {
    public static final float VERSION= 1.0f;
    public static final String API_END_POINT= "dweet.io";
    public static boolean USE_SSL= true;
    private static final JsonParser jsonParser= new JsonParser();
    public static void setSSLEnabled(boolean enable)
    {
        USE_SSL= enable;
    }
    public static boolean isSSLEnabled()
    {
        return USE_SSL;
    }
    public static boolean removeLock(String lock, String key) throws IOException
    {
        if(lock== null || key == null)
            throw new NullPointerException();

        lock= URLEncoder.encode(lock,"UTF-8");
        key= URLEncoder.encode(key,"UTF-8");

        URL url= new URL(getAPIEndPointURL()+"/remove/lock/"+lock+"?key="+key);
        HttpURLConnection connection= (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("GET");

        JsonObject response= readResponse(connection.getInputStream());

        connection.disconnect();

        return response.has("this") && response.get("this").getAsString().equals("succeeded");
    }
    public static boolean unlock(String thingName, String key) throws IOException
    {
        if(key == null || thingName == null)
            throw new NullPointerException();

        thingName = URLEncoder.encode(thingName, "UTF-8");
        key = URLEncoder.encode(key, "UTF-8");

        URL url = new URL(getAPIEndPointURL() + "/unlock/" + thingName + "?key=" + key);
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("GET");

        JsonObject response = readResponse(connection.getInputStream());

        connection.disconnect();

        return response.has("this") && response.get("this").getAsString().equals("succeeded");
    }
    public static boolean createAlert(String thingName, String recipients, String condition, String key) throws IOException
    {
        if(thingName == null || recipients == null || condition == null)
            throw new NullPointerException();

        condition= condition.trim();
        if(condition.length() > 2000)
        {
            throw new IOException("condition script is too large (above 2000 characters) ");
        }

        thingName = URLEncoder.encode(thingName, "UTF-8");
        recipients= URLEncoder.encode(recipients, "UTF-8");
        condition= URLEncoder.encode(condition, "UTF-8");

        URL url= new URL(getAPIEndPointURL()+ "/alert/"+recipients+"/when/"+ thingName+"/"+condition+((key==null)?"":"?key="+URLEncoder.encode(key,"UTF-8")));

        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("GET");

        JsonObject response= readResponse(connection.getInputStream());

        connection.disconnect();

        return (response.has("this") && response.get("this").getAsString().equals("succeeded"));
    }
    public static boolean removeAlert(String thingName, String key) throws IOException
    {
        if(key == null || thingName == null)
            throw new NullPointerException();

        thingName = URLEncoder.encode(thingName, "UTF-8");
        key = URLEncoder.encode(key, "UTF-8");

        URL url = new URL(getAPIEndPointURL() + "/remove/alert/for/" + thingName + "?key=" + key);
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("GET");

        JsonObject response = readResponse(connection.getInputStream());

        connection.disconnect();

        return response.has("this") && response.get("this").getAsString().equals("succeeded");
    }
    public static boolean lock(String thingName, String lock, String key) throws IOException
    {
        if(key == null || lock == null || thingName == null)
            throw new NullPointerException();

        thingName = URLEncoder.encode(thingName, "UTF-8");
        lock= URLEncoder.encode(lock,"UTF-8");
        key= URLEncoder.encode(key,"UTF-8");

        URL url= new URL(getAPIEndPointURL()+"/lock/"+thingName+"?lock="+lock+"&key="+key);
        HttpURLConnection connection= (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("GET");

        JsonObject response= readResponse(connection.getInputStream());

        connection.disconnect();

        return response.has("this") && response.get("this").getAsString().equals("succeeded");
    }
    public static boolean publish(String thingName, JsonElement content) throws IOException
    {
        return publish(thingName, content, null);
    }
    public static boolean publish(String thingName, JsonElement content, String key) throws IOException
    {
        if(thingName == null || content == null)
            throw new NullPointerException();

        thingName = URLEncoder.encode(thingName, "UTF-8");

        URL url= new URL(getAPIEndPointURL()+ "/dweet/for/"+ thingName+((key==null)?"":"?key="+URLEncoder.encode(key,"UTF-8")));

        HttpURLConnection connection= (HttpURLConnection) url.openConnection();
        connection.setRequestProperty("Content-Type", "application/json; charset=utf-8");
        connection.setRequestMethod("POST");
        connection.setDoInput(true);
        connection.setDoOutput(true);

        PrintWriter out= new PrintWriter(connection.getOutputStream());
        out.println(content.toString());
        out.flush();
        out.close();

        JsonObject response= readResponse(connection.getInputStream());

        connection.disconnect();

        return (response.has("this") && response.get("this").getAsString().equals("succeeded"));
    }
    public static void listen(String thingName, DweetListener listener)
    {
        listen(thingName, listener, null);
    }
    public static void listen(String thingName, DweetListener listener, String key)
    {
        if(thingName == null || listener == null)
            throw new NullPointerException();
        try
        {
            thingName = URLEncoder.encode(thingName, "UTF-8");

            URL url= new URL(getAPIEndPointURL()+ "/listen/for/dweets/from/"+ thingName+((key==null)?"":"?key="+URLEncoder.encode(key,"UTF-8")));
            HttpURLConnection connection= (HttpURLConnection) url.openConnection();
            connection.setRequestProperty("Content-Type", "application/json");
            connection.setRequestMethod("GET");

            Scanner scan= new Scanner(connection.getInputStream());
            String line;

            while(scan.hasNextLine())
            {
                if(!listener.isStillListeningTo(thingName))
                    break;
                line= scan.nextLine().trim();

                if(line.indexOf('{') == -1 || line.lastIndexOf('}') == -1)
                    continue;
                line= line.substring(line.indexOf('{'), line.lastIndexOf('}') + 1);
                line= line.replace("\\\"", "\"").replace("\\\\", "\\");

                listener.dweetReceived(new Dweet(jsonParser.parse(line)));
            }
            scan.close();
            connection.disconnect();
            listener.stoppedListening(thingName);
        }
        catch(Exception e)
        {
            listener.connectionLost(thingName, e);
        }
    }
    public static List<Dweet> getAllDweets(String thingName) throws IOException, ParseException
    {
        return getAllDweets(thingName, null);
    }
    public static List<Dweet> getAllDweets(String thingName, String key) throws IOException, ParseException
    {
        if(thingName == null)
            throw new NullPointerException();

        thingName = URLEncoder.encode(thingName, "UTF-8");

        URL url= new URL(getAPIEndPointURL()+"/get/dweets/for/"+thingName+((key==null)?"":"?key="+URLEncoder.encode(key,"UTF-8")));

        HttpURLConnection connection= (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("GET");

        JsonObject response= readResponse(connection.getInputStream());

        connection.disconnect();

        if(response.has("this") && response.get("this").getAsString().equals("succeeded"))
        {
            List<Dweet> dweets= new LinkedList<Dweet>();

            JsonArray arr= response.getAsJsonArray("with");
            Iterator<JsonElement> it= arr.iterator();

            while(it.hasNext())
                dweets.add(new Dweet(it.next()));

            return dweets;
        }
        return null;
    }
    public static Dweet getLatestDweet(String thingName) throws IOException, ParseException
    {
        return getLatestDweet(thingName, null);
    }

    public static Dweet getLatestDweet(String thingName, String key) throws IOException, ParseException
    {
        if(thingName == null)
            throw new NullPointerException();

        thingName = URLEncoder.encode(thingName, "UTF-8");

        URL url= new URL(getAPIEndPointURL()+"/get/latest/dweet/for/"+thingName+((key==null)?"":"?key="+URLEncoder.encode(key,"UTF-8")));
        HttpURLConnection connection= (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("GET");

        JsonObject response= readResponse(connection.getInputStream());

        connection.disconnect();

        if(response.has("this") && response.get("this").getAsString().equals("succeeded"))
        {
            JsonArray arr= response.getAsJsonArray("with");
            if(arr.size() == 0)
                return null;
            return new Dweet(arr.remove(0));
        }
        return null;
    }
    public static String getAPIEndPointURL()
    {
        return "http"+((USE_SSL)?"s":"")+"://"+API_END_POINT;
    }

    private static JsonObject readResponse(InputStream in)
    {
        Scanner scan= new Scanner(in);
        StringBuilder sn= new StringBuilder();
        while(scan.hasNext())
            sn.append(scan.nextLine()).append('\n');
        scan.close();
        return jsonParser.parse( sn.toString()).getAsJsonObject();
    } }

Dweet.Java

public class Dweet {
    private static final DateFormat date_format= new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
    private final JsonElement jsonDweet;
    private final String thingName;
    private final Date createdDate;
    private final JsonObject content;

    protected Dweet(JsonElement jsonDweet) throws ParseException
    {
        this.jsonDweet= jsonDweet;
        JsonObject j= jsonDweet.getAsJsonObject();
        thingName= j.get("thing").getAsString();
        content= j.get("content").getAsJsonObject();
        String date_string= j.get("created").getAsString();
        createdDate= date_format.parse(date_string);
    }
    public String getThingName()
    {
        return thingName;
    }
    public Date getCreationDate()
    {
        return createdDate;
    }
    public JsonObject getContent()
    {
        return content;
    }
    @Override
    public String toString()
    {
        return jsonDweet.toString();
    }

}