如何延迟函数调用？ [复制]

Posted 2023-02-25

【中文标题】如何延迟函数调用？ [复制]

【英文标题】：How can I delay a funtion call? [duplicate]

【发布时间】：2019-03-05 01:53:19

【问题描述】：

public class NotificationReceivedCheckDelivery extends NotificationExtenderService 
   @Override
   protected boolean onNotificationProcessing(OSNotificationReceivedResult receivedResult) 
      OverrideSettings overrideSettings = new OverrideSettings();

      overrideSettings.extender = new NotificationCompat.Extender() 
         @Override
         public NotificationCompat.Builder extend(NotificationCompat.Builder builder) 
            // Sets the background notification color to Yellow on android 5.0+ devices.
            return builder.setColor(new BigInteger("FFFFEC4F", 16).intValue());
         
      ;

      OSNotificationDisplayedResult displayedResult = displayNotification(overrideSettings);
    Log.d("ONES",receivedResult.payload.title);
      JSONObject AdditionalData = receivedResult.payload.additionalData;
        Log.d("Adata",AdditionalData.toString());

      String uuid= null;
      try
        //   "uuid":"adddd"
          uuid = AdditionalData.getString("uuid");

      
      catch (JSONException e)
          Log.e("Error JSON","UUID",e);
      



                // Create Object and call AsyncTask execute Method
                new FetchNotificationData().execute(uuid);

      return true;
   



private class FetchNotificationData extends AsyncTask<String,Void, String> 

        @Override
        protected String doInBackground(String... uuids) 
            // These two need to be declared outside the try/catch
            // so that they can be closed in the finally block.
            HttpURLConnection urlConnection = null;
            BufferedReader reader = null;

            // Will contain the raw JSON response as a string.
            String forecastJsonStr = null;

            try 

                URL url = new URL("http://test.com/AppDeliveryReport?uuid="+uuids[0]);


                urlConnection = (HttpURLConnection) url.openConnection();
                urlConnection.setRequestMethod("GET");
                urlConnection.connect();

                // Read the input stream into a String
                InputStream inputStream = urlConnection.getInputStream();
                StringBuffer buffer = new StringBuffer();
                if (inputStream == null) 
                    // Nothing to do.
                    return null;
                
                reader = new BufferedReader(new InputStreamReader(inputStream));

                String line;
                while ((line = reader.readLine()) != null) 
                    // Since it's JSON, adding a newline isn't necessary (it won't affect parsing)
                    // But it does make debugging a *lot* easier if you print out the completed
                    // buffer for debugging.
                    buffer.append(line + "\n");
                

                if (buffer.length() == 0) 
                    // Stream was empty.  No point in parsing.
                    return null;
                
                forecastJsonStr = buffer.toString();
                return forecastJsonStr;
             catch (IOException e) 
                Log.e("PlaceholderFragment", "Error ", e);
                // If the code didn't successfully get the weather data, there's no point in attemping
                // to parse it.
                return null;
             catch (Exception e) 
                e.printStackTrace();
                return null;
             finally 
                if (urlConnection != null) 
                    urlConnection.disconnect();
                
                if (reader != null) 
                    try 
                        reader.close();
                     catch (final IOException e) 
                        Log.e("PlaceholderFragment", "Error closing stream", e);
                    
                
            

        

        @Override
        protected void onPostExecute(String s) 
            super.onPostExecute(s);
            Log.i("json", s);
        

我想随机延迟调用 FetchNotificationData 函数。 这是一个交付报告 url 请求功能。每当应用程序收到来自 onesignal 的通知时，它都会调用该 url。我不想一次用巨大的请求炸毁服务器。所以我想用随机秒数延迟调用，这样服务器就必须在给定的时间服务几个调用。

【问题讨论】：

您可以使用Handler。

使用 System.sleep(1000);

你能帮忙吗？这是我的反应原生应用程序。我对 Java 了解不多

【参考方案1】：

 timer = new Timer();
 final int FPS = 3;
 TimerTask updateBall = new UpdateBallTask();
 timer.scheduleAtFixedRate(updateBall, 0, 1000 * FPS);

类：

class UpdateBallTask extends TimerTask 
    public void run() 
        // do work
    

///或

  final Handler handler = new Handler();
    final Runnable r = new Runnable() 
        public void run() 
           handler.postDelayed(this, 100);
           // do work
                handler.removeCallbacksAndMessages(null);          
        
    ;
   handler.postDelayed(r, 100);

【参考方案2】：

你可以像这样使用Handler

  Handler handler = new Handler();
        handler.postDelayed(new Runnable() 
            @Override
            public void run() 
               // your FetchNotificationData function
            
        ,timeInMiliSec);

记得将Handler 导入为android.os，而不是java.util.logging

【讨论】：

@Ali Ahmed 的回答和你的回答有什么区别？

你说得对，我想我们俩都在同时准备答案，但他确实发送得更快

所以我只需要把这段代码放在onNotificationProcessing 函数中就可以了？基本上我对Java编码一无所知

是的，只要把这个方法放在你想调用“获取通知数据”的地方，然后把你的“获取通知数据”方法放在里面..

【参考方案3】：

你可以使用handler来延迟函数调用

  new Handler().postDelayed(new Runnable() 
                @Override
                public void run() 
                    Toast.makeText(Splash.this, "I will be called after 2 sec", 
                                                              Toast.LENGTH_SHORT).show();
                    //Call your Function here..
                
            , 2000); // 2000 = 2 sec