我想在没有用户交互的情况下自动打印

Question

当用户点击 UI 中的按钮时，PrintManager 会生成要打印的 Document。然后用户点击打印图标推送打印命令。

以上部分已经完成。 但要求是： 我想删除用户必须单击打印图标（图中显示的打印图标，由 PrintDocumentAdapter 生成）并自动生成/打印文档。

再次： 我已经实现了打印功能，我只想删除用户交互。当生成下图时，打印命令会自动执行，无需用户点击打印图标。

Answer 1

不要使用 PrintManager，您可以使用 android.print 包中的 PdfPrint.java 类进行打印。

将此代码放在 java/android/print 中（在您的包之外）

package android.print;

import android.os.CancellationSignal;
import android.os.ParcelFileDescriptor;
import android.util.Log;

import java.io.File;

public class PdfPrint {

    private static final String TAG = PdfPrint.class.getSimpleName();
    private final PrintAttributes printAttributes;

    public PdfPrint(PrintAttributes printAttributes) {
        this.printAttributes = printAttributes;
    }

    public void print(final PrintDocumentAdapter printAdapter, final File path, final String fileName) {
        printAdapter.onLayout(null, printAttributes, null, new PrintDocumentAdapter.LayoutResultCallback() {
            @Override
            public void onLayoutFinished(PrintDocumentInfo info, boolean changed) {
                printAdapter.onWrite(new PageRange[]{PageRange.ALL_PAGES}, getOutputFile(path, fileName), new CancellationSignal(), new PrintDocumentAdapter.WriteResultCallback() {
                    @Override
                    public void onWriteFinished(PageRange[] pages) {
                        super.onWriteFinished(pages);
                    }
                });
            }
        }, null);
    }

    private ParcelFileDescriptor getOutputFile(File path, String fileName) {
        if (!path.exists()) {
            path.mkdirs();
        }
        File file = new File(path, fileName);
        try {
            file.createNewFile();
            return ParcelFileDescriptor.open(file, ParcelFileDescriptor.MODE_READ_WRITE);
        } catch (Exception e) {
            Log.e(TAG, "Failed to open ParcelFileDescriptor", e);
        }
        return null;
    }
}

你可以使用这样的代码（从 webview 打印）

private fun createWebPrintJob(webView: WebView, date: Long) {
        try {
            val jobName = getString(R.string.app_name) + " Document"
            val attributes = PrintAttributes.Builder()
                .setMediaSize(PrintAttributes.MediaSize.NA_LEGAL)
                .setResolution(PrintAttributes.Resolution("pdf", "pdf", 600, 600))
                .setMinMargins(PrintAttributes.Margins.NO_MARGINS).build()
            val path =
                Environment.getExternalStoragePublicDirectory("/pdf_output")

            val pdfPrint = PdfPrint(attributes)
            pdfPrint.print(
                webView.createPrintDocumentAdapter(jobName),
                path,
                "output_$date.pdf"
            )
            Log.i("pdf", "pdf created")
        } catch (e: Exception) {
            Log.e("pdf", " pdf failed e.localizedMessage")
        }
    }

Answer 2

你可以试试这个：

 private void doPhotoPrint() {

        if (imageLoader == null) {
            imageLoader = new GlideImageLoader(this);
        }

        if (!IMG_PATH.isEmpty()) {

            imageLoader.bindImageAsBitmap(null, FileUtils.validateFileUrl(IMG_PATH), new RequestListener<Bitmap>() {
                @Override
                public boolean onLoadFailed(@Nullable GlideException e, Object model, Target<Bitmap> target, boolean isFirstResource) {
                    return false;
                }

                @Override
                public boolean onResourceReady(Bitmap resource, Object model, Target<Bitmap> target, DataSource dataSource, boolean isFirstResource) {
                    return false;
                }
            }, new SimpleTarget<Bitmap>() {
                @Override
                public void onResourceReady(@NonNull Bitmap resource, @Nullable Transition<? super Bitmap> transition) {
                    Activity activity = ShareImgActivity.this;
                    if (resource != null && AppUtils.isValidContext(activity)) {
                        PrintHelper photoPrinter = new PrintHelper(activity);
                        photoPrinter.setScaleMode(PrintHelper.SCALE_MODE_FIT);
                        photoPrinter.printBitmap(getString(R.string.app_name) + "_Print", resource);
                    }
                }
            }, Priority.IMMEDIATE);
        }
    }

Answer 3

对于 PrintManager 的实现，你可以看看下面的代码行：

来源： https://developer.android.com/training/printing/custom-docs.html

private void doPrint() {
    // Get a PrintManager instance
    PrintManager printManager = (PrintManager) getActivity()
            .getSystemService(Context.PRINT_SERVICE);

    // Set job name, which will be displayed in the print queue
    String jobName = getActivity().getString(R.string.app_name) + " Document";

    // Start a print job, passing in a PrintDocumentAdapter implementation
    // to handle the generation of a print document
    printManager.print(jobName, new MyPrintDocumentAdapter(getActivity()),
            null); //
}