android - Printing PDF directly using PrintManager Android 4.4

Question

http://developer.android.com/training/printing/index.html documentation tells how to print a custom content by rendering it on a PDF canvas and sending thus created PDF document for printing. But has no information about if we already have a PDF document, how to send it for printing?

Does similar to bitmap printing, there is some method like printHelper.printPDF?

Answer 1

在 onWrite() 方法中使用以下代码片段应该可以做到：

InputStream input = null;
OutputStream output = null;
try {
    input = new FileInputStream(new File("somefile.pdf"));
    output = new FileOutputStream(destination.getFileDescriptor());
    byte[] buf = new byte[1024];
    int bytesRead;
    while ((bytesRead = input.read(buf)) > 0) {
         output.write(buf, 0, bytesRead);
    }
} catch (Exception e) {

} finally {
    try {
        input.close();
        output.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

Answer 2

所以这就是我所做的......

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
}
@RequiresApi(api = Build.VERSION_CODES.KITKAT)
public void clicked(View view){ //Button To start print
    PrintManager printManager = (PrintManager) this.getSystemService(Context.PRINT_SERVICE);
    String jobName = this.getString(R.string.app_name) + " Document";
    printManager.print(jobName, pda, null);
}
PrintDocumentAdapter pda = new PrintDocumentAdapter()
{

    @RequiresApi(api = Build.VERSION_CODES.KITKAT)
    @Override
    public void onWrite(PageRange[] pages, ParcelFileDescriptor destination, CancellationSignal cancellationSignal, WriteResultCallback callback)
    {
        InputStream input = null;
        OutputStream output = null;
        try {
            input = new FileInputStream(new File("/storage/emulated/0/Download/file_name.pdf"));
            output = new FileOutputStream(destination.getFileDescriptor());
            byte[] buf = new byte[1024];
            int bytesRead;
            while ((bytesRead = input.read(buf)) > 0) {
                output.write(buf, 0, bytesRead);
            }
        }
        catch (Exception e) {

        } finally {
            try {
                input.close();
                output.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        callback.onWriteFinished(new PageRange[]{PageRange.ALL_PAGES});
    }

    @RequiresApi(api = Build.VERSION_CODES.KITKAT)
    @Override
    public void onLayout(PrintAttributes oldAttributes, PrintAttributes newAttributes, CancellationSignal cancellationSignal, LayoutResultCallback callback, Bundle extras)
    {
        if (cancellationSignal.isCanceled())
        {
            callback.onLayoutCancelled();
            return;
        }

        //int pages = computePageCount(newAttributes);

        PrintDocumentInfo pdi = new PrintDocumentInfo.Builder("file_name.pdf").setContentType(PrintDocumentInfo.CONTENT_TYPE_DOCUMENT).build();
        callback.onLayoutFinished(pdi, true);
    }
};
}

安卓清单 >>>

添加权限

    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

我的手机不支持 sd 卡，但我还是写了 READ_EXTERNAL_STORAGE