如何在 Android PrintService 中访问与 PrintJob 对象关联的文件？

Question

我已经遵循了这个 PrintService 示例存储库中的很多代码：Zaki50 PrintService。我试图做的唯一不同的事情是从与 PrintJob 关联的文件中获取字节。现在我有了 FileDescriptor，但不知道如何使用它来获取实际的文件数据！任何帮助将不胜感激。

Answer 1

好的，这是代码中的答案：

final PrintJobInfo info = printJob.getInfo();
final File file = new File(getFilesDir(), info.getLabel());


InputStream in = null;
FileOutputStream out = null;

try {
   in = new 
   FileInputStream(printJob.getDocument().getData().getFileDescriptor());
   out = new FileOutputStream(file);

   byte[] buffer = new byte[1024];
   int read;
   while ((read = in.read(buffer)) != -1) {
          out.write(buffer, 0, read);
   }
   in.close();

   out.flush();
   out.close();

} catch (IOException ioe) {

}

FileChannel channel = null;
byte[] fileBytes = null;
try {
       RandomAccessFile raf = new RandomAccessFile(file, "r");
       channel = raf.getChannel();
       ByteBuffer bb = ByteBuffer.NEW(channel.map(
             FileChannel.MapMode.READ_ONLY, 0, channel.size()));
       fileBytes  = new byte[bb.remaining()];
       bb.get(fileBytes , 0, fileBytes .length);

} catch (FileNotFoundException e) {
       e.printStackTrace();
} catch (IOException e) {
       e.printStackTrace();
}

fileBytes数组的内容是打印文件的实际字节数。

如何在 Android PrintService 中访问与 PrintJob 对象关联的文件？

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