android 打印

您好，要在 Android 应用程序中进行打印，可以使用 Android 打印框架（Android Printing Framework）。以下是一个简单的示例，演示如何使用打印框架：

1. 在 AndroidManifest.xml 文件中添加打印机权限：

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.NFC" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<uses-permission android:name="android.permission.VIBRATE" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.WRITE_SETTINGS" />
<uses-permission android:name="android.permission.WRITE_SYNC_SETTINGS" />

<uses-feature
    android:name="android.hardware.usb.host"
    android:required="false" />
<uses-feature
    android:name="android.hardware.nfc"
    android:required="false" />
<uses-feature
    android:name="android.hardware.camera"
    android:required="false" />
<uses-feature
    android:name="android.hardware.bluetooth"
    android:required="false" />

2. 在您的应用程序中创建一个打印类，实现PrintDocumentAdapter接口

public class MyPrintDocumentAdapter extends PrintDocumentAdapter {
    private Context mContext;
    private PrintedPdfDocument mPdfDocument;
    private int mPageHeight;
    private int mPageWidth;
    private int mTotalPages;

    public MyPrintDocumentAdapter(Context context) {
        mContext = context;
    }

    @Override
    public void onStart() {
        super.onStart();

        // 初始化打印文档
        mPdfDocument = new PrintedPdfDocument(mContext, getPrintAttributes());
    }

    @Override
    public void onFinish() {
        super.onFinish();

        // 释放资源
        mPdfDocument.close();
        mPdfDocument = null;
    }

    @Override
    public void onLayout(PrintAttributes oldAttributes, PrintAttributes newAttributes, CancellationSignal cancellationSignal, LayoutResultCallback callback, Bundle extras) {
        // 获取打印页面大小
        mPageHeight = newAttributes.getMediaSize().getHeightMils() / 1000 * 72;
        mPageWidth = newAttributes.getMediaSize().getWidthMils() / 1000 * 72;

        // 计算总页数
        mTotalPages = 1;

        // 检查是否取消打印
        if (cancellationSignal.isCanceled()) {
            callback.onLayoutCancelled();
            return;
        }

        // 创建打印页面
        PrintDocumentInfo.Builder builder = new PrintDocumentInfo.Builder("print_output.pdf")
                .setContentType(PrintDocumentInfo.CONTENT_TYPE_DOCUMENT)
                .setPageCount(mTotalPages);

        PrintDocumentInfo info = builder.build();
        callback.onLayoutFinished(info, true);
    }

    @Override
    public void onWrite(PageRange[] pages, ParcelFileDescriptor destination, CancellationSignal cancellationSignal, WriteResultCallback callback) {
        // 创建渲染器
        PdfRenderer renderer = new PdfRenderer(mPdfDocument);

        // 渲染每一页
        for (int i = 0; i < mTotalPages; i++) {
            // 检查是否取消打印
            if (cancellationSignal.isCanceled()) {
                callback.onWriteCancelled();
                renderer.close();
                return;
            }

            // 获取打印页面
            PdfRenderer.Page page = renderer.openPage(i);

            // 创建画布
            Bitmap bitmap = Bitmap.createBitmap(mPageWidth, mPageHeight, Bitmap.Config.ARGB_8888);
            Canvas canvas = new Canvas(bitmap);

            // 将页面渲染到画布上
            page.render(bitmap, null, null, PdfRenderer.Page.RENDER_MODE_FOR_PRINT);

            // 将画布保存到 PDF 文档中
            PdfDocument.Page pdfPage = mPdfDocument.startPage(i + 1);
            canvas.drawBitmap(bitmap, 0, 0, null);
            mPdfDocument.finishPage(pdfPage);

            // 释放资源
            page.close();
        }

        // 写入 PDF 文档到输出流
        try {
            OutputStream outputStream = new FileOutputStream(destination.getFileDescriptor());
            mPdfDocument.writeTo(outputStream);
            callback.onWriteFinished(new PageRange[]{PageRange.ALL_PAGES});
        } catch (IOException e) {
            callback.onWriteFailed(e.toString());
        } finally {
            mPdfDocument.close();
            mPdfDocument = null;
            renderer.close();
        }
    }
}

3. 在您的应用程序中调用打印服务

PrintManager printManager = (PrintManager) getSystemService(Context.PRINT_SERVICE);
String jobName = getString(R.string.app_name) + " Document";
printManager.print(jobName, new MyPrintDocumentAdapter(this), null);

以上是一个简单的示例，演示如何使用打印框架在 Android 应用程序中进行打印。您可以根据您的需求进行修改和扩展。