悬挂应用程序的多个异步任务

Question

在我的Android应用程序中,我使用THREAD_POOL_EXECUTOR使用多个AsyncTask,这使得任务并行运行.有时应用程序挂起.以下是我使用的代码.

1. 你能告诉我如何微调以避免任何悬挂问题吗？

2. 如何找到应用程序挂起的点？

   new fetchInitialCoinsParallel().executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, url);
   
   prefCoinList = getPrefCoin();
   if(prefCoinList.size()>0){
       for(int i=0;i<prefCoinList.size();i++){
           new fetchAltCoinsParallel().executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, url);
       }
   }
   
   public class fetchAltCoinsParallel extends AsyncTask<String, String, String> {
   @Override
   protected void onPreExecute() {
   }
   
   protected String doInBackground(String... params) {
       try {
           InputStream is = getDataFromURL(params[0]);
           if(is!=null){
               BufferedReader br = new BufferedReader(new InputStreamReader(is));
               synchronized(this){
                   brList.add(br);
               }
   
           }else{
               prefCoinNotLoadedTimeOutCount=prefCoinNotLoadedTimeOutCount+1;
           }
   
   
           if(brList.size()==prefCoinList.size()-prefCoinNotLoadedTimeOutCount){
               try {
                   loadAltCoins(getAltCoinDataParallel());
               } catch (IOException e) {
                   e.printStackTrace();
               }
   
               maingame.dataReady=true;
           }
   
       } catch (IOException e) {
           e.printStackTrace();
       } 
       return null;
   }
   
   protected void onPostExecute(String params) {
   }
   protected void onProgressUpdate(String... progress) {
   }
   

   }

线程细节

Answer 1

检查这个AsyncTaskLoader概念。此功能由 API 级别 11 中引入的 Android 社​​区以及 Honeycomb 功能支持。

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AsyncTaskLoader解决了 AsyncTask.java 的许多限制和解决方案

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官方：https://developer.android.com/reference/android/content/AsyncTaskLoader.html

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好的示例：https://medium.com/google-developers/making-loading-data-on-android-lifecycle-aware-897e12760832

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public class JsonAsyncTaskLoader extends AsyncTaskLoader<List<String>> {\n    // You probably have something more complicated\n    // than just a String. Roll with me\n    private List<String> mData;\n\n    public JsonAsyncTaskLoader(Context context) {\n        super(context);\n    }\n\n    @Override\n    protected void onStartLoading() {\n        if (mData != null) {\n            // Use cached data\n            deliverResult(mData);\n        } else {\n            // We have no data, so kick off loading it\n            forceLoad();\n        }\n    }\n\n    @Override\n    public List<String> loadInBackground() {\n        // This is on a background thread\n        // Good to know: the Context returned by getContext()\n        // is the application context\n        File jsonFile = new File(\n                getContext().getFilesDir(), "downloaded.json");\n        List<String> data = new ArrayList<>();\n        // Parse the JSON using the library of your choice\n        // Check isLoadInBackgroundCanceled() to cancel out early\n        return data;\n    }\n\n    @Override\n    public void deliverResult(List<String> data) {\n        // We\xe2\x80\x99ll save the data for later retrieval\n        mData = data;\n        // We can do any pre-processing we want here\n        // Just remember this is on the UI thread so nothing lengthy!\n        super.deliverResult(data);\n    }\n}\n

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