Android app automatic updates

Source code introduction

Automatic updates are possible even if the phone does not have an SD card. I have tested this myself.
Source code screenshot

Source code snippet

 int down_step = down_step_custom; // Prompt step  
 int totalSize; //Total file size  
 int downloadCount = 0 ; // The size of the downloaded files  
 int updateCount = 0 ; // The size of the uploaded file   
          
        InputStream inputStream;
        OutputStream outputStream; 
  
        URL url = new URL(down_url);
        HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
        httpURLConnection.setConnectTimeout(TIMEOUT);
        httpURLConnection.setReadTimeout(TIMEOUT);
 // Get the size of the downloaded file  
        totalSize = httpURLConnection.getContentLength(); 
          
 if (httpURLConnection.getResponseCode() == 404 ) {
 throw   new Exception( "fail!" );
 //This place should add a download failure process, but because we added a try---catch outside, the Exception has been handled.  
 //So no need to process  
 } 
          
        inputStream = httpURLConnection.getInputStream();
 outputStream = new FileOutputStream(file, false ); // Overwrite if the file exists   
          
 byte buffer[] = new   byte [ 1024 ];
 int readsize = 0 ; 
          
 while ((readsize = inputStream.read(buffer)) != - 1 ) { 
              
 // /************If an error occurs during the download process, an error message will pop up and the notificationManager will be canceled*********/  
 // if (httpURLConnection.getResponseCode() == 404) {  
 // notificationManager.cancel(R.layout.notification_item);  
 // throw new Exception("fail!");  
 // //This place should add a download failure processing, but because we added a try---catch outside, the Exception has been handled.  
 // //So no need to process  
 // }   
                          
            outputStream.write(buffer, 0 , readsize);
 downloadCount += readsize; // Get the downloaded size from time to time  
 /*** 3% increase each time**/  
 if (updateCount == 0 || (downloadCount * 100 / totalSize - down_step) >= updateCount) {
                updateCount += down_step;
 // Change the notification bar  
                contentView.setTextViewText(R.id.notificationPercent,updateCount + "%" );
                contentView.setProgressBar(R.id.notificationProgress, 100 ,updateCount, false );
                notification.contentView = contentView;
                notificationManager.notify(R.layout.notification_item, notification);
 }
 }
 if (httpURLConnection != null ) {
            httpURLConnection.disconnect();
 }
 inputStream.close();
 outputStream.close(); 
          
 return downloadCount;