Android实现PDF预览打印功能

private void onPrintPdf() {
    PrintManager printManager = (PrintManager) getSystemService(Context.PRINT_SERVICE);
    PrintAttributes.Builder builder = new PrintAttributes.Builder();
    builder.setColorMode(PrintAttributes.COLOR_MODE_COLOR);
    printManager.print("test pdf print", new MyPrintAdapter(this,filePath), builder.build());
  }

package com.android.guocheng.printdemo;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.pdf.PdfDocument;
import android.graphics.pdf.PdfDocument.PageInfo;
import android.graphics.pdf.PdfRenderer;
import android.os.Bundle;
import android.os.CancellationSignal;
import android.os.ParcelFileDescriptor;
import android.print.PageRange;
import android.print.PrintAttributes;
import android.print.PrintDocumentAdapter;
import android.print.PrintDocumentInfo;
import android.print.pdf.PrintedPdfDocument;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

/**
 * Created by guocheng on 2017/6/13.
 */
public class MyPrintAdapter extends PrintDocumentAdapter {

  private Context context;
  private int pageHeight;
  private int pageWidth;
  private PdfDocument mPdfDocument;
  private int totalpages = 1;
  private String pdfPath;
  private List<Bitmap> mlist;

  public MyPrintAdapter(Context context,String pdfPath) {
    this.context = context;
    this.pdfPath = pdfPath;
  }

  @Override
  public void onLayout(PrintAttributes oldAttributes, PrintAttributes newAttributes, CancellationSignal cancellationSignal,
             LayoutResultCallback callback,
             Bundle metadata) {

    mPdfDocument = new PrintedPdfDocument(context, newAttributes); //创建可打印PDF文档对象

    pageHeight = newAttributes.getMediaSize().ISO_A4.getHeightMils() * 72 / 1000; //设置尺寸
    pageWidth = newAttributes.getMediaSize().ISO_A4.getWidthMils() * 72 / 1000;

    if (cancellationSignal.isCanceled()) {
      callback.onLayoutCancelled();
      return;
    }

    ParcelFileDescriptor mFileDescriptor = null;
    PdfRenderer pdfRender = null;
    PdfRenderer.Page page = null;
    try {
      mFileDescriptor = ParcelFileDescriptor.open(new File(pdfPath), ParcelFileDescriptor.MODE_READ_ONLY);
      if (mFileDescriptor != null)
        pdfRender = new PdfRenderer(mFileDescriptor);

      mlist = new ArrayList<>();

      if (pdfRender.getPageCount() > 0) {
        totalpages = pdfRender.getPageCount();
        for (int i = 0; i < pdfRender.getPageCount(); i++) {
          if(null != page)
            page.close();
          page = pdfRender.openPage(i);
          Bitmap bmp = Bitmap.createBitmap(page.getWidth()*2,page.getHeight()*2, Bitmap.Config.ARGB_8888);
          page.render(bmp, null, null, PdfRenderer.Page.RENDER_MODE_FOR_DISPLAY);
          mlist.add(bmp);
        }
      }
      if(null != page)
        page.close();
      if(null != mFileDescriptor)
        mFileDescriptor.close();
      if (null != pdfRender)
        pdfRender.close();
    } catch (FileNotFoundException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }

    if (totalpages > 0) {
      PrintDocumentInfo.Builder builder = new PrintDocumentInfo
          .Builder("快速入门.pdf")
          .setContentType(PrintDocumentInfo.CONTENT_TYPE_DOCUMENT)
          .setPageCount(totalpages); //构建文档配置信息

      PrintDocumentInfo info = builder.build();
      callback.onLayoutFinished(info, true);
    } else {
      callback.onLayoutFailed("Page count is zero.");
    }
  }

  @Override
  public void onWrite(final PageRange[] pageRanges, final ParcelFileDescriptor destination, final CancellationSignal cancellationSignal,
            final WriteResultCallback callback) {
    for (int i = 0; i < totalpages; i++) {
      if (pageInRange(pageRanges, i)) //保证页码正确
      {
        PageInfo newPage = new PageInfo.Builder(pageWidth,
            pageHeight, i).create();
        PdfDocument.Page page =
            mPdfDocument.startPage(newPage); //创建新页面

        if (cancellationSignal.isCanceled()) { //取消信号
          callback.onWriteCancelled();
          mPdfDocument.close();
          mPdfDocument = null;
          return;
        }
        drawPage(page, i); //将内容绘制到页面Canvas上
        mPdfDocument.finishPage(page);
      }
    }

    try {
      mPdfDocument.writeTo(new FileOutputStream(
          destination.getFileDescriptor()));
    } catch (IOException e) {
      callback.onWriteFailed(e.toString());
      return;
    } finally {
      mPdfDocument.close();
      mPdfDocument = null;
    }

    callback.onWriteFinished(pageRanges);
  }

  private boolean pageInRange(PageRange[] pageRanges, int page) {
    for (int i = 0; i < pageRanges.length; i++) {
      if ((page >= pageRanges[i].getStart()) &&
          (page <= pageRanges[i].getEnd()))
        return true;
    }
    return false;
  }

  //页面绘制（渲染）
  private void drawPage(PdfDocument.Page page,int pagenumber) {
    Canvas canvas = page.getCanvas();
    if(mlist != null){
      Paint paint = new Paint();
      Bitmap bitmap = mlist.get(pagenumber);
      int bitmapWidth = bitmap.getWidth();
      int bitmapHeight = bitmap.getHeight();
      // 计算缩放比例
      float scale = (float)pageWidth/(float)bitmapWidth;
      // 取得想要缩放的matrix参数
      Matrix matrix = new Matrix();
      matrix.postScale(scale, scale);
      canvas.drawBitmap(bitmap,matrix,paint);
    }
  }

}