generate PDF from Android using PrintedPdfDocument and View.draw

Question

I have this layout, and I would like to print everything on the screen to PDF. including all the content in the scroll view. I will also try to do this using IText later, but for now I want to see if I can do it using PrintedPdfDocument and View.draw. What I have generates the PDF but only part of the layout is visible on the PDF.

The full project is on: https://github.com/ammar5001/PrintPDF2

Here is the layout:

<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>

and here is the method I am using:

  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

A work-around would be to create a bitmap the size of the view, put it in a canvas and pass to View.draw(). Then you can scale the bitmap and draw it to the pdf canvas. You could even section it onto multiple pages.

Keep in mind, the view is measured in pixels while the pdf canvas measures in points or 1/72inch.

I'll add some code to my answer tomorrow.

EDIT: Here's some working code to get any view onto a pdf or to a printer:

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)});
}
}