4. Prerequisites
SDK platform 19
SDK build-tools 19 or later
Something to print with
A Google Cloud Print Ready printer
A printer shared through Google Cloud Print
Print to PDF
6. PrintManager
PrintManager printManager = (PrintManager)
context.getSystemService(Context.PRINT_SERVICE);
PrintJob printJob = printManager.print(
printJobName, documentAdapter, attributes);
Name for the print job
(shown to the user)
Default print job attributes
Adapter that emits the document
8. PrintDocumentAdapter
Web pages
// Create a WebView and start printing when its ready
WebView webView = new WebView(context);
webView.setWebViewClient(new WebViewClient() {
@Override
public void onPageFinished(
WebView webView, String url) {
// Print to it as before
PrintDocumentAdapter documentAdapter =
webView.createPrintDocumentAdapter();
}
});
webView.loadUrl(url);
10. Custom Print Adapters
Events:
onStart()
Print process has begun.
onLayout()
A print setting has changed and the layout of the pages needs to be computed.
Must return expected number of pages.
onWrite()
Render printed pages into a file.
onFinish()
Print process has ended.
11. Custom Print Adapters
onLayout()
public void onLayout(
final PrintAttributes oldAttributes,
final PrintAttributes newAttributes,
final CancellationSignal cancellationSignal,
final LayoutResultCallback callback,
final Bundle metadata) {
CONTRACT
onLayoutFinished(
PrintDocumentInfo, boolean)
}
onLayoutCancelled()
onLayoutFailed(CharSequence)
12. Custom Print Adapters
onLayout()
Create a document for printing:
PrintedPdfDocument document =
new PrintedPdfDocument(context, newAttributes);
Compute the number of pages using PrintAttributes
Return print information to the print framework:
PrintDocumentInfo info = new PrintDocumentInfo
.Builder("print_output.pdf")
.setContentType(
PrintDocumentInfo.CONTENT_TYPE_DOCUMENT)
.setPageCount(pages);
.build();
callback.onLayoutFinished(info, true);
Wait for the print framework to invoke onWrite()
13. Custom Print Adapters
onWrite()
public void onWrite(
final PageRange[] pages,
final ParcelFileDescriptor destination,
final CancellationSignal cancellationSignal,
final WriteResultCallback callback) {
CONTRACT
onWriteFinished(PageRange[])
}
onWriteCancelled()
onWriteFailed(CharSequence)
14. Custom Print Adapters
onWrite()
Start writing a page:
Page page = document.startPage(pageNumber);
Draw onto the page canvas:
page.getCanvas();
Note that elements are specified in points (1/72 inch)
Finish writing the page:
document.finishPage(page);
Inform WriteResultCallback of the PageRange[] printed
15. Custom Print Adapters
Caveats
If you need a screen context, remember that the printer and screen densities differ!
Obtain the printer density:
printerDensity = Math.max(
newAttributes.getResolution().getHorizontalDpi(),
newAttributes.getResolution().getVerticalDpi());
Create a new Context to cope with a different Configuration:
Configuration configuration = new Configuration();
configuration.densityDpi = printerDensity;
printContext = createConfigurationContext(
configuration);
Use this context for creating new views:
View view = new LinearLayout(printContext);
view.draw(page.getCanvas());
16. PrintHelper
PrintHelper printHelper = new PrintHelper(context);
// Instruct how the content should scale
printHelper.setScaleMode(PrintHelper.SCALE_MODE_FIT);
// Get the bitmap for the ImageView's drawable
Bitmap bitmap = ((BitmapDrawable)
mImageView.getDrawable()).getBitmap();
// Print the bitmap
printHelper.printBitmap("Print Bitmap", bitmap);
