Android webview转PDF的教程

compile 'org.droidparts.dexmaker:dexmaker-mockito:1.5'

File file = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM + "/PDFTest.pdf");
  File dexCacheFile;
  // 获取需要打印的webview适配器
  PrintDocumentAdapter printAdapter;
  PageRange[] ranges;
  ParcelFileDescriptor descriptor;

  /**
   a* @param webView
   */
  private void printPDFFile(WebView webView) {
    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.KITKAT) {
      /**
       * android 5.0之后，出于对动态注入字节码安全性德考虑，已经不允许随意指定字节码的保存路径了，需要放在应用自己的包名文件夹下。
       */
      //新的创建DexMaker缓存目录的方式，直接通过context获取路径
      dexCacheFile = getDir("dex", 0);
      if (!dexCacheFile.exists()) {
        dexCacheFile.mkdir();
      }

      try {
        //创建待写入的PDF文件，pdfFilePath为自行指定的PDF文件路径
        if (file.exists()) {
          file.delete();
        }
        file.createNewFile();
        descriptor = ParcelFileDescriptor.open(file, ParcelFileDescriptor.MODE_READ_WRITE);

        // 设置打印参数
        PrintAttributes attributes = new PrintAttributes.Builder()
            .setMediaSize(PrintAttributes.MediaSize.ISO_A4)
            .setResolution(new PrintAttributes.Resolution("id", Context.PRINT_SERVICE, 300, 300))
            .setColorMode(PrintAttributes.COLOR_MODE_COLOR)
            .setMinMargins(PrintAttributes.Margins.NO_MARGINS)
            .build();
        //打印所有界面
        ranges = new PageRange[]{PageRange.ALL_PAGES};

        printAdapter = webView.createPrintDocumentAdapter();
        // 开始打印
        printAdapter.onStart();
        printAdapter.onLayout(attributes, attributes, new CancellationSignal(), getLayoutResultCallback(new InvocationHandler() {
          @Override
          public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
            if (method.getName().equals("onLayoutFinished")) {
              // 监听到内部调用了onLayoutFinished()方法，即打印成功
              onLayoutSuccess();
            } else {
              // 监听到打印失败或者取消了打印

            }
            return null;
          }
        }, dexCacheFile.getAbsoluteFile()), new Bundle());
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
  }

  /**
   * @throws IOException
   */
  private void onLayoutSuccess() throws IOException {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
      PrintDocumentAdapter.WriteResultCallback callback = getWriteResultCallback(new InvocationHandler() {
        @Override
        public Object invoke(Object o, Method method, Object[] objects) throws Throwable {
          if (method.getName().equals("onWriteFinished")) {
            Toast.makeText(MainActivity.this,"Success",Toast.LENGTH_SHORT).show();
            // PDF文件写入本地完成，导出成功
            Log.e("onLayoutSuccess","onLayoutSuccess");
          } else {
            Toast.makeText(MainActivity.this,"导出失败",Toast.LENGTH_SHORT).show();
          }
          return null;
        }
      }, dexCacheFile.getAbsoluteFile());
      //写入文件到本地
      printAdapter.onWrite(ranges, descriptor, new CancellationSignal(), callback);
    }else {
      Toast.makeText(MainActivity.this,"不支持4.4.以下",Toast.LENGTH_SHORT).show();

    }
  }

  @SuppressLint("NewApi")
  public static PrintDocumentAdapter.LayoutResultCallback getLayoutResultCallback(InvocationHandler invocationHandler, File dexCacheDir) throws IOException {
    return ProxyBuilder.forClass(PrintDocumentAdapter.LayoutResultCallback.class)
        .dexCache(dexCacheDir)
        .handler(invocationHandler)
        .build();
  }

  @SuppressLint("NewApi")
  public static PrintDocumentAdapter.WriteResultCallback getWriteResultCallback(InvocationHandler invocationHandler, File dexCacheDir) throws IOException {
    return ProxyBuilder.forClass(PrintDocumentAdapter.WriteResultCallback.class)
        .dexCache(dexCacheDir)
        .handler(invocationHandler)
        .build();
  }