下载zip文件并将其保存在SD卡中

Question

我有一个应用程序来下载zip文件并保存到SD卡。但是我在读取输入流时得到zipentry=null，它不会进入while块。有人可以帮我解决这个问题吗？

         try {
           // fileInputStream = new InputStream(input);
            ZipInputStream zipInputStream 
             = new ZipInputStream(new BufferedInputStream(input));
            ZipEntry zipEntry=zipInputStream.getNextEntry();

            Toast.makeText(getApplicationContext(), "I have entered try block zipentry"+zipEntry,Toast.LENGTH_LONG).show();
            System.out.println("Zipentry is"+zipEntry);

            while ((zipEntry = zipInputStream.getNextEntry()) != null){
                Toast.makeText(getApplicationContext(), "Entered into while block",Toast.LENGTH_LONG).show();

             String zipEntryName = zipEntry.getName();
             File file = new File(to + zipEntryName);

             if (file.exists()){

             } else {
              if(zipEntry.isDirectory()){
               file.mkdirs(); 
              }else{
               byte buffer[] = new byte[BUFFER_SIZE];
               FileOutputStream fileOutputStream = new FileOutputStream(file);
               bufferedOutputStream 
                = new BufferedOutputStream(fileOutputStream, BUFFER_SIZE);
               int count;

               while ((count 
                = zipInputStream.read(buffer, 0, BUFFER_SIZE)) != -1) {
                bufferedOutputStream.write(buffer, 0, count);
               }

               bufferedOutputStream.flush();
               bufferedOutputStream.close(); 
              }

            }
            zipInputStream.close();
           } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
               Toast.makeText(getApplicationContext(), "File not found",Toast.LENGTH_LONG).show();
            e.printStackTrace();
           }catch (IOException e) {
            // TODO Auto-generated catch block
               Toast.makeText(getApplicationContext(), "Input outout error",Toast.LENGTH_LONG).show();
            e.printStackTrace();
           }

Answer 1

在while循环中，条件之前已经有一个ZipEntry zipEntry=zipInputStream.getNextEntry();。将其保留并仅在while循环中初始化它。类似的东西：

 ZipEntry zipEntry;     
 while ((zipEntry = zipInputStream.getNextEntry()) != null){
  //
}