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);
}
}
}