Question

我已经使用了Asyntask，我正在尝试下载图像并将其保存到手机的SD卡中。 OnPostExecute我再次调用asyntask，它始终保持打开状态。但是经过一个小时左右的应用程序开始说ANR，我应该如何处理这个场景。

    public class DownloadSavePics extends AsyncTask<Void, Void, String> {
        Context context;
        String Tag = "DownloadSavePics";
        String res;
        QVSEngine qvsEngine;
        String IID; 
        String url1 = "";
        String deviceId ="";
        String FileName ="";

        /*
         * Pass all data required to log in and handle the result here.
         */

        public DownloadSavePics(Context context,String url1,String deviceId) {
            this.context = context;
            this.deviceId = deviceId;
            this.url1 = url1;
            qvsEngine = new QVSEngine(context,null);        
        }

        @Override
        protected void onPreExecute() { 
            Log.i(Tag, "inside pre execute");
        }

        /*
         * Do all the network IO and time-consuming parsing in here, this method
         * will be invoked in its own thread, not blocking the UI.
         */

        protected String doInBackground(Void... params) {
            /*
             * the background thread calls the method CallService 
             * 
             */
            if (qvsEngine.checkInternetConnection()){   
                CallService();  
            }
            return FileName;        
        }

        public void CallService (){
            /*
             *  downloading the file
             */
            try {
                if(qvsEngine.checkInternetConnection()){
                    /*
                     * requested for connection so set the led1 as amber 
                     */
                    try {
                        URL imgURL = new URL(url1);
                        Log.e(Tag,"Downloading from hotspot "+url1);
                        URLConnection ucon = imgURL.openConnection();
                        InputStream is = ucon.getInputStream();
                        BufferedInputStream bis = new BufferedInputStream(is);
                        ByteArrayBuffer baf = new ByteArrayBuffer(50);
                        int current = 0;                    
                        while ((current = bis.read()) != -1) {
                            baf.append((byte) current);
                        }
/*saving the file in the sdcard
*/                                  
                        String FileName = deviceId.trim()+".jpg";                   
                        String path = Environment.getExternalStorageDirectory().toString()+"/school/snaps/"+FileName;;
                        FileOutputStream fos = new FileOutputStream(path);
                        fos.write(baf.toByteArray());
                        fos.close();                                    
                    }catch(Exception e){
                        Log.e(Tag,""+e);
                    } 
                }
            }catch(Exception e){
                Log.e(Tag,""+e);
            }
        }


        @Override
        protected void onPostExecute(String result) {
            try {
                qvsEngine.database.RunQuery("insert into webcam values (null,'"+FileName+"','0')");
                Log.e(Tag,"webcame table has :  "+ qvsEngine.RunQuery("select count(imgid) from webcam where path ='"+FileName+"'") );      
            }catch(Exception e){
                Log.e(Tag,""+e);
            }   
            new DownloadSavePics(context,url1,deviceId).execute();
        }

    }

Answer 1

是的，您将获得“应用程序无响应”，因为

你正在打电话

 new DownloadSavePics(context,url1,deviceId).execute();

在onPostExecute中

，所以它会再次执行DownloadSavePics，当到达onPostExecute时，它会再次接到一个电话....所以没有结束。

连续通话DownlaodSavePics来电ANR

Answer 2

尝试通过runOnUIThread（）从Runnable执行新实例。如果它没有帮助，请发布日志。

这是一个想法：也许你的任务无法来下载数据（例如WiFi已经腐烂），而然后你生成无限循环即时执行任务。尝试添加sleep（500）（在工作线程中）并查看是否有帮助。

Asynctask下载和保存图像导致ANGER

2 个答案: