android - 使用 PrintedPdfDocument 和 View.draw 从 Android 生成 PDF

Question

我有这个布局，我想将屏幕上的所有内容打印成 PDF。包括 ScrollView 中的所有内容。稍后我还将尝试使用 IText 来执行此操作，但现在我想看看我是否可以使用 PrintedPdfDocument 和 View.draw 来执行此操作。我生成的 PDF 但只有部分布局在 PDF 上可见。

完整项目在:<强> https://github.com/ammar5001/PrintPDF2

这是布局:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity"
android:id="@+id/relativeLayout">

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Title"
    android:id="@+id/textView"
    android:textSize="24dp"
    android:textStyle="bold"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true" />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/textView2"
    android:text="Auther Name\nTitle\nContacts"
    android:textSize="16dp"
    android:layout_below="@+id/textView"
    android:layout_alignParentStart="true" />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Some Company\nStreet Address\nCity, State\nzip code"
    android:id="@+id/textView3"
    android:layout_below="@+id/textView"
    android:layout_alignParentEnd="true"
    android:textSize="16dp"
    android:layout_marginBottom="10dp" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Print PDF"
    android:id="@+id/button1"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    android:onClick="printPDF" />

<ScrollView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/scrollView"
    android:layout_below="@id/textView3"
    android:layout_above="@id/button1"
    android:layout_marginTop="10dp">

    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="For some applications, such as drawing apps, page layout apps and other apps that focus on graphic output, creating beautiful printed pages is a key feature. In this case, it is not enough to print an image or an HTML document. The print output for these types of applications requires precise control of everything that goes into a page, including fonts, text flow, page breaks, headers, footers, and graphic elements."
            android:id="@+id/textView4"
            android:layout_marginBottom="10dp" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Creating print output that is completely customized for your application requires more programming investment than the previously discussed approaches. You must build components that communicate with the print framework, adjust to printer settings, draw page elements and manage printing on multiple pages.  This lesson shows you how you connect with the print manager, create a print adapter and build content for printing."
            android:id="@+id/textView5"
            android:layout_marginBottom="10dp"/>

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="When your application manages the printing process directly, the first step after receiving a print request from your user is to connect to the Android print framework and obtain an instance of the PrintManager class. This class allows you to initialize a print job and begin the printing lifecycle. The following code example shows how to get the print manager and start the printing process"
            android:id="@+id/textView6"
            android:layout_marginBottom="10dp"/>

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="The example code above demonstrates how to name a print job and set an instance of the PrintDocumentAdapter class which handles the steps of the printing lifecycle. The implementation of the print adapter class is discussed in the next section."
            android:id="@+id/textView7"
            android:layout_marginBottom="10dp"/>
    </LinearLayout>
</ScrollView>
</RelativeLayout>

这是我正在使用的方法:

  public void printPDF(View view){
    if(isExternalStorageWritable()) {
        String filename = getFileName();
        File file = new File(getAlbumStorageDir("PDF"), filename);
        try {
            FileOutputStream outputStream = new FileOutputStream(file);
            createPDF(outputStream);
        } catch (IOException e) {
            e.printStackTrace();
            Toast.makeText(this, e.getMessage(), Toast.LENGTH_LONG).show();
        }
    }
}

private void createPDF(FileOutputStream outputStream) throws IOException {
    PrintedPdfDocument document = new PrintedPdfDocument(this,
            getPrintAttributes());

    // start a page
    PdfDocument.Page page = document.startPage(1);

    // draw something on the page
    View content = getContentView();
    content.draw(page.getCanvas());

    // finish the page
    document.finishPage(page);
    //. . .
    // add more pages
    //. . .
    // write the document content
    document.writeTo(outputStream);

    //close the document
    document.close();
}


private View getContentView() {
    return findViewById(R.id.relativeLayout);
}

Answer 1

解决方法是创建一个与 View 大小相同的位图，将其放在 Canvas 中并传递给 View.draw()。然后您可以缩放位图并将其绘制到 pdf Canvas 上。您甚至可以将其分成多个页面。

请记住， View 以像素为单位，而 pdf Canvas 以点或 1/72 英寸为单位。

明天我会在我的答案中添加一些代码。

编辑:这里有一些工作代码可以查看 pdf 或打印机:

public void printPDF(View view) {
    PrintManager printManager = (PrintManager) getSystemService(PRINT_SERVICE);
    printManager.print("print_any_view_job_name", new ViewPrintAdapter(this,
            findViewById(R.id.relativeLayout)), null);
}

public class ViewPrintAdapter extends PrintDocumentAdapter {

private PrintedPdfDocument mDocument;
private Context mContext;
private View mView;

public ViewPrintAdapter(Context context, View view) {
    mContext = context;
    mView = view;
}

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

    mDocument = new PrintedPdfDocument(mContext, newAttributes);

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

    PrintDocumentInfo.Builder builder = new PrintDocumentInfo
            .Builder("print_output.pdf")
            .setContentType(PrintDocumentInfo.CONTENT_TYPE_DOCUMENT)
            .setPageCount(1);

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

@Override
public void onWrite(PageRange[] pages, ParcelFileDescriptor destination,
                    CancellationSignal cancellationSignal,
                    WriteResultCallback callback) {

    // Start the page
    PdfDocument.Page page = mDocument.startPage(0);
    // Create a bitmap and put it a canvas for the view to draw to. Make it the size of the view
    Bitmap bitmap = Bitmap.createBitmap(mView.getWidth(), mView.getHeight(),
            Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(bitmap);
    mView.draw(canvas);
    // create a Rect with the view's dimensions.
    Rect src = new Rect(0, 0, mView.getWidth(), mView.getHeight());
    // get the page canvas and measure it.
    Canvas pageCanvas = page.getCanvas();
    float pageWidth = pageCanvas.getWidth();
    float pageHeight = pageCanvas.getHeight();
    // how can we fit the Rect src onto this page while maintaining aspect ratio?
    float scale = Math.min(pageWidth/src.width(), pageHeight/src.height());
    float left = pageWidth / 2 - src.width() * scale / 2;
    float top = pageHeight / 2 - src.height() * scale / 2;
    float right = pageWidth / 2 + src.width() * scale / 2;
    float bottom = pageHeight / 2 + src.height() * scale / 2;
    RectF dst = new RectF(left, top, right, bottom);

    pageCanvas.drawBitmap(bitmap, src, dst, null);
    mDocument.finishPage(page);

    try {
        mDocument.writeTo(new FileOutputStream(
                destination.getFileDescriptor()));
    } catch (IOException e) {
        callback.onWriteFailed(e.toString());
        return;
    } finally {
        mDocument.close();
        mDocument = null;
    }
    callback.onWriteFinished(new PageRange[]{new PageRange(0, 0)});
}
}