来自 JSON 的通知服务

Question

如何通知？ 如何查看新闻的日期并在有新闻时显示通知？ 服务是否可以从Fragment 获取 SharedPref 并检查然后发出通知？

TabFragment1.class代码：

@Override
protected void onPostExecute(StringBuilder stringBuilder) {

    try {
        JSONObject jsonObject = new JSONObject(stringBuilder.toString());
        JSONArray array = jsonObject.getJSONArray("articles");
        for (int i = 0; i < array.length(); i++) {
            JSONObject object = array.getJSONObject(i);
            String title = object.getString("title");
            String desc = object.getString("description");
            String imageUrl = object.getString("urlToImage");
            String articleUrl = object.getString("url");
            String newsdata = object.getString("publishedAt");

            sPref = getActivity().getSharedPreferences("MyPref", MODE_PRIVATE);
            SharedPreferences.Editor ed = sPref.edit();
            ed.putString(SAVED_TEXT, newsdata);
            ed.commit();
            Toast.makeText(getActivity(), "Text saved", Toast.LENGTH_SHORT).show();
            News news = new News(title, desc, imageUrl, articleUrl);
            myAdapter.addNews(news);

            myAdapter.notifyDataSetChanged();
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}

通知服务代码：

public class Notification extends Service {
    String datanews;
    String titlenotif;
    String destnotif;
    MyAsynk asynk;
    final String SAVED_TEXT = "saved_text";
    String checker;
    SharedPreferences sPref;

    @Override
    public void onCreate() {
        super.onCreate();
        Timer timer = new Timer();
        timer.schedule(new UpdateTimeTask(), 0, 1800000); //тикаем каждые 30 мinute без задержки 1800000
    }

    class UpdateTimeTask extends TimerTask {
        public void run() {
            sPref = getSharedPreferences("MyPref",MODE_PRIVATE);
            String savedText = sPref.getString(SAVED_TEXT, "");
            checker = sPref.getString(savedText, "0");

            if(datanews != checker){
                asynk = new MyAsynk();
                asynk.execute();
                createNotification(getApplicationContext());//пушим уведомление
            } else {
                asynk = new MyAsynk();
                asynk.execute();
            }
        }
    }

    class MyAsynk extends AsyncTask<Void,Void,StringBuilder> {
        @Override
        protected StringBuilder doInBackground(Void... voids) {
            StringBuilder stringBuilder = new StringBuilder();
            String key = "0aa2713d5a1a4aad9a914c9294f6a22b";
            try {
                URL url = new URL("https://newsapi.org/v1/articles?source=the-next-web&sortBy=latest&apiKey=" + key);
                URLConnection uc = url.openConnection();
                uc.connect();
                BufferedInputStream in = new BufferedInputStream(uc.getInputStream());
                int ch;
                while ((ch = in.read()) != -1) {
                    stringBuilder.append((char) ch);
                }
            } catch (Exception e) {e.printStackTrace();}

            return stringBuilder;
        }

        @Override
        protected void onPostExecute(StringBuilder stringBuilder) {
            try {
                JSONObject jsonObject = new JSONObject(stringBuilder.toString());
                JSONArray array = jsonObject.getJSONArray("articles");
                for (int i = 0; i < array.length(); i++) {
                    JSONObject object = array.getJSONObject(i);
                    String title = object.getString("title");
                    String desc = object.getString("description");
                    String newsdata = object.getString("publishedAt");
                    datanews = newsdata;
                    titlenotif = title;
                    destnotif = desc;
                }
            }
            catch (Exception e){e.printStackTrace();}
        }
    }

    private void createNotification(Context context) {
        NotificationManager manager = (NotificationManager) context.getSystemService(NOTIFICATION_SERVICE);
        NotificationCompat.Builder ncBuilder = new NotificationCompat.Builder(context);
        Intent intent = new Intent(this, MainActivity.class);
        PendingIntent pIntent = PendingIntent.getActivity(this, 0, intent, 0);
        ncBuilder.setVibrate(new long[]{500});
        ncBuilder.setLights(Color.WHITE, 3000, 3000);
        ncBuilder.setSound(Settings.System.DEFAULT_NOTIFICATION_URI);
        ncBuilder.setContentIntent(pIntent);
        ncBuilder.setContentTitle(titlenotif + "");
        ncBuilder.setContentText(destnotif + "");
        ncBuilder.setTicker("You have news!");
        ncBuilder.setSmallIcon(R.drawable.news_icon);
        ncBuilder.setAutoCancel(true);
        manager.notify((int)System.currentTimeMillis(),ncBuilder.build());
    }
    public IBinder onBind(Intent arg0) {
        return null;
    }
}

Answer 1

是的Service 可以阅读SharedPreference 并可以发出通知。

如果我理解正确，您需要在 MyAsynk 类的 onPostExecute 函数中创建通知。

因此，您可以尝试像这样在 AsyncTask 中添加公共属性。

class MyAsynk extends AsyncTask<Void,Void,StringBuilder> {

    public boolean showNotification;

    // .. Other functions
}

现在在你的UpdateTimerTask

if(datanews != checker){
    asynk = new MyAsynk();
    asynk.showNotification = true;
    asynk.execute();
} else {
    asynk = new MyAsynk();
    asynk.showNotification = false;
    asynk.execute();
}

现在在MyAsynk 类的onPostExecute 中，您需要检查布尔值并相应地创建通知。

@Override
protected void onPostExecute(StringBuilder stringBuilder) {
    try {
        JSONObject jsonObject = new JSONObject(stringBuilder.toString());
        JSONArray array = jsonObject.getJSONArray("articles");
        for (int i = 0; i < array.length(); i++) {
            JSONObject object = array.getJSONObject(i);
            String title = object.getString("title");
            String desc = object.getString("description");
            String newsdata = object.getString("publishedAt");
            datanews = newsdata;
            titlenotif = title;
            destnotif = desc;
        }

        // Create notification here on demand
        if(showNotification) createNotification(getApplicationContext);
    }
    catch (Exception e){e.printStackTrace();}
}

更新

来自评论

也许有必要检查出版日期 新闻，用当前日期验证它并显示通知..所以你 有新闻时才需要显示通知

如果您打算仅从客户端跟踪新消息，则可能需要进行大量编码，包括保留本地存储以及每次是否有新消息到达时检查。我猜你需要在这里有一个服务器端实现。当收到新消息时，它将向您发送推送通知。服务器应处理同步和其他机制。