am 720963a7: Merge "docs: Print API training for KitKat release" into klp-dev
* commit '720963a71425e3cdc03c7b243e8869cebee51931': docs: Print API training for KitKat release
This commit is contained in:
362
docs/html/training/printing/custom-docs.jd
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362
docs/html/training/printing/custom-docs.jd
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@@ -0,0 +1,362 @@
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page.title=Printing Custom Documents
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parent.title=Printing Content
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parent.link=index.html
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trainingnavtop=true
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next.title=
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next.link=
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@jd:body
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<div id="tb-wrapper">
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<div id="tb">
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<h2>This lesson teaches you to</h2>
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<ol>
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<li><a href="#print-manager">Connect to the Print Manager</a></li>
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<li><a href="#print-adapter">Create a Print Adapter</a>
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<ol>
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<li><a href="#doc-info">Compute print document info</a></li>
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<li><a href="#write-file">Write a print document file</a></li>
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</ol>
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</li>
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<li><a href="#draw-content">Drawing PDF Page Content</a></li>
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</ol>
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</div>
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</div>
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<p>For some applications, such as drawing apps, page layout apps and other apps that focus on
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graphic output, creating beautiful printed pages is a key feature. In this case, it is not enough
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to print an image or an HTML document. The print output for these types of applications requires
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precise control of everything that goes into a page, including fonts, text flow, page breaks,
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headers, footers, and graphic elements.</p>
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<p>Creating print output that is completely customized for your application requires more
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programming investment than the previously discussed approaches. You must build components that
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communicate with the print framework, adjust to printer settings, draw page elements and
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manage printing on multiple pages.</p>
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<p>This lesson shows you how you connect with the print manager, create a print adapter and
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build content for printing.</p>
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<h2 id="print-manager">Connect to the Print Manager</h2>
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<p>When your application manages the printing process directly, the first step after receiving a
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print request from your user is to connect to the Android print framework and obtain an instance
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of the {@link android.print.PrintManager} class. This class allows you to initialize a print job
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and begin the printing lifecycle. The following code example shows how to get the print manager
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and start the printing process.</p>
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<pre>
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private void doPrint() {
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// Get a PrintManager instance
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PrintManager printManager = (PrintManager) getActivity()
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.getSystemService(Context.PRINT_SERVICE);
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// Set job name, which will be displayed in the print queue
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String jobName = getActivity().getString(R.string.app_name) + " Document";
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// Start a print job, passing in a PrintDocumentAdapter implementation
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// to handle the generation of a print document
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printManager.print(jobName, new MyPrintDocumentAdapter(getActivity()),
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null); //
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}
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</pre>
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<p>The example code above demonstrates how to name a print job and set an instance of the {@link
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android.print.PrintDocumentAdapter} class which handles the steps of the printing lifecycle. The
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implementation of the print adapter class is discussed in the next section.</p>
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<p class="note">
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<strong>Note:</strong> The last parameter in the {@link android.print.PrintManager#print print()}
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method takes a {@link android.print.PrintAttributes} object. You can use this parameter to
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provide hints to the printing framework and pre-set options based on the previous printing cycle,
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thereby improving the user experience. You may also use this parameter to set options that are
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more appropriate to the content being printed, such as setting the orientation to landscape
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when printing a photo that is in that orientation.
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</p>
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<h2 id="print-adapter">Create a Print Adapter</h2>
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<p>A print adapter interacts with the Android print framework and handles the steps of the
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printing process. This process requires users to select printers and print options before creating
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a document for printing. These selections can influence the final output as the user chooses
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printers with different output capabilities, different page sizes, or different page orientations.
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As these selections are made, the print framework asks your adapter to lay out and generate a
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print document, in preparation for final output. Once a user taps the print button, the framework
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takes the final print document and passes it to a print provider for output. During the printing
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process, users can choose to cancel the print action, so your print adapter must also listen for
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and react to a cancellation requests.</p>
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<p>The {@link android.print.PrintDocumentAdapter} abstract class is designed to handle the
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printing lifecycle, which has four main callback methods. You must implement these methods
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in your print adapter in order to interact properly with the print framework:</p>
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<ul>
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<li>{@link android.print.PrintDocumentAdapter#onStart onStart()} - Called once at the
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beginning of the print process. If your application has any one-time preparation tasks to
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perform, such as getting a snapshot of the data to be printed, execute them here. Implementing
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this method in your adapter is not required.</li>
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<li>{@link android.print.PrintDocumentAdapter#onLayout onLayout()} - Called each time a
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user changes a print setting which impacts the output, such as a different page size,
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or page orientation, giving your application an opportunity to compute the layout of the
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pages to be printed. At the minimum, this method must return how many pages are expected
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in the printed document.</li>
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<li>{@link android.print.PrintDocumentAdapter#onWrite onWrite()} - Called to render printed
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pages into a file to be printed. This method may be called one or more times after each
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{@link android.print.PrintDocumentAdapter#onLayout onLayout()} call.</li>
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<li>{@link android.print.PrintDocumentAdapter#onFinish onFinish()} - Called once at the end
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of the print process. If your application has any one-time tear-down tasks to perform,
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execute them here. Implementing this method in your adapter is not required.</li>
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</ul>
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<p>The following sections describe how to implement the layout and write methods, which are
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critical to the functioning of a print adapter.</p>
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<p class="note">
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<strong>Note:</strong> These adapter methods are called on the main thread of your application. If
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you expect the execution of these methods in your implementation to take a significant amount of
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time, implement them to execute within a separate thread. For example, you can encapsulate the
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layout or print document writing work in separate {@link android.os.AsyncTask} objects.
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</p>
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<h3 id="doc-info">Compute print document info</h3>
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<p>Within an implementation of the {@link android.print.PrintDocumentAdapter} class, your
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application must be able to specify the type of document it is creating and calculate the total
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number of pages for print job, given information about the printed page size.
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The implementation of the {@link android.print.PrintDocumentAdapter#onLayout onLayout()} method in
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the adapter makes these calculations and provides information about the expected output of the
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print job in a {@link android.print.PrintDocumentInfo} class, including the number of pages and
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content type. The following code example shows a basic implementation of the {@link
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android.print.PrintDocumentAdapter#onLayout onLayout()} method for a {@link
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android.print.PrintDocumentAdapter}:
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<pre>
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@Override
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public void onLayout(PrintAttributes oldAttributes,
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PrintAttributes newAttributes,
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CancellationSignal cancellationSignal,
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LayoutResultCallback callback,
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Bundle metadata) {
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// Create a new PdfDocument with the requested page attributes
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mPdfDocument = new PrintedPdfDocument(getActivity(), newAttributes);
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// Respond to cancellation request
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if (cancellationSignal.isCancelled() ) {
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callback.onLayoutCancelled();
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return;
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}
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// Compute the expected number of printed pages
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int pages = computePageCount(newAttributes);
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if (pages > 0) {
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// Return print information to print framework
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PrintDocumentInfo info = new PrintDocumentInfo
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.Builder("print_output.pdf")
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.setContentType(PrintDocumentInfo.CONTENT_TYPE_DOCUMENT)
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.setPageCount(pages);
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.build();
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// Content layout reflow is complete
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callback.onLayoutFinished(info, true);
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} else {
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// Otherwise report an error to the print framework
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callback.onLayoutFailed("Page count calculation failed.");
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}
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}
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</pre>
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<p>The execution of {@link android.print.PrintDocumentAdapter#onLayout onLayout()} method can
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have three outcomes: completion, cancellation, or failure in the case where calculation of the
|
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layout cannot be completed. You must indicate one of these results by calling the appropriate
|
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method of the {@link android.print.PrintDocumentAdapter.LayoutResultCallback} object.</p>
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<p class="note">
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<strong>Note:</strong> The boolean parameter of the
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{@link android.print.PrintDocumentAdapter.LayoutResultCallback#onLayoutFinished
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onLayoutFinished()} method indicates whether or not the layout content has actually changed
|
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since the last request. Setting this parameter properly allows the print framework to avoid
|
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unnecessarily calling the {@link android.print.PrintDocumentAdapter#onWrite onWrite()} method,
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essentially caching the previously written print document and improving performance.
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</p>
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<p>The main work of {@link android.print.PrintDocumentAdapter#onLayout onLayout()} is
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calculating the number of pages that are expected as output given the attributes of the printer.
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How you calculate this number is highly dependent on how your application lays out pages for
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printing. The following code example shows an implementation where the number of pages is
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determined by the print orientation:</p>
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<pre>
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private int computePageCount(PrintAttributes printAttributes) {
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int itemsPerPage = 4; // default item count for portrait mode
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MediaSize pageSize = printAttributes.getMediaSize();
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if (!pageSize.isPortrait()) {
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// Six items per page in landscape orientation
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itemsPerPage = 6;
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}
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// Determine number of print items
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int printItemCount = getPrintItemCount();
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return (int) Math.ceil(printItemCount / itemsPerPage);
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}
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</pre>
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<h3 id="write-file">Write a print document file</h3>
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<p>When it is time to write print output to a file, the Android print framework calls the {@link
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android.print.PrintDocumentAdapter#onWrite onWrite()} method of your application's {@link
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android.print.PrintDocumentAdapter} class. The method's parameters specify which pages should be
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written and the output file to be used. Your implementation of this method must then render each
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requested page of content to a multi-page PDF document file. When this process is complete, you
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call the {@link android.print.PrintDocumentAdapter.WriteResultCallback#onWriteFinished
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onWriteFinished()} method of the callback object.</p>
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<p class="note">
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<strong>Note:</strong> The Android print framework may call the {@link
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android.print.PrintDocumentAdapter#onWrite onWrite()} method one or more times for every
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call to {@link android.print.PrintDocumentAdapter#onLayout onLayout()}. For this reason, it is
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important to set the boolean parameter of
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{@link android.print.PrintDocumentAdapter.LayoutResultCallback#onLayoutFinished
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onLayoutFinished()} method to {@code false} when the print content layout has not changed,
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to avoid unnecessary re-writes of the print document.
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</p>
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<p class="note">
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<strong>Note:</strong> The boolean parameter of the
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{@link android.print.PrintDocumentAdapter.LayoutResultCallback#onLayoutFinished
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onLayoutFinished()} method indicates whether or not the layout content has actually changed
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since the last request. Setting this parameter properly allows the print framework to avoid
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unnecessarily calling the {@link android.print.PrintDocumentAdapter#onLayout onLayout()} method,
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essentially caching the previously written print document and improving performance.
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</p>
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<p>The following sample demonstrates the basic mechanics of this process using the {@link
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android.print.pdf.PrintedPdfDocument} class to create a PDF file:</p>
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<pre>
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@Override
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public void onWrite(final PageRange[] pageRanges,
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final ParcelFileDescriptor destination,
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final CancellationSignal cancellationSignal,
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final WriteResultCallback callback) {
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// Iterate over each page of the document,
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// check if it's in the output range.
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for (int i = 0; i < totalPages; i++) {
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// Check to see if this page is in the output range.
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if (containsPage(pageRanges, i)) {
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// If so, add it to writtenPagesArray. writtenPagesArray.size()
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// is used to compute the next output page index.
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writtenPagesArray.append(writtenPagesArray.size(), i);
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PdfDocument.Page page = mPdfDocument.startPage(i);
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// check for cancellation
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if (cancellationSignal.isCancelled()) {
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callback.onWriteCancelled();
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mPdfDocument.close();
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mPdfDocument = null;
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return;
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}
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// Draw page content for printing
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drawPage(page);
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// Rendering is complete, so page can be finalized.
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mPdfDocument.finishPage(page);
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}
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}
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// Write PDF document to file
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try {
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mPdfDocument.writeTo(new FileOutputStream(
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destination.getFileDescriptor()));
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} catch (IOException e) {
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callback.onWriteFailed(e.toString());
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return;
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} finally {
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mPdfDocument.close();
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mPdfDocument = null;
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}
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PageRange[] writtenPages = computeWrittenPages();
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// Signal the print framework the document is complete
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callback.onWriteFinished(writtenPages);
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...
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}
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</pre>
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<p>This sample delegates rendering of PDF page content to <code>drawPage()</code>
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method, which is discussed in the next section.
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</p>
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<p>As with layout, execution of {@link android.print.PrintDocumentAdapter#onWrite onWrite()}
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||||
method can have three outcomes: completion, cancellation, or failure in the case where the
|
||||
the content cannot be written. You must indicate one of these results by calling the
|
||||
appropriate method of the {@link android.print.PrintDocumentAdapter.WriteResultCallback} object.
|
||||
</p>
|
||||
|
||||
|
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<p class="note">
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||||
<strong>Note:</strong> Rendering a document for printing can be a resource-intensive operation. In
|
||||
order to avoid blocking the main user interface thread of your application, you should consider
|
||||
performing the page rendering and writing operations on a separate thread, for example
|
||||
in an {@link android.os.AsyncTask}.
|
||||
For more information about working with execution threads like asynchronous tasks,
|
||||
see <a href="{@docRoot}guide/components/processes-and-threads.html">Processes
|
||||
and Threads</a>.
|
||||
</p>
|
||||
|
||||
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||||
<h2 id="draw-content">Drawing PDF Page Content</h2>
|
||||
|
||||
<p>When your application prints, your application must generate a PDF document and pass it to
|
||||
the Android print framework for printing. You can use any PDF generation library for this
|
||||
purpose. This lesson shows how to use the {@link android.print.pdf.PrintedPdfDocument} class
|
||||
to generate PDF pages from your content.</p>
|
||||
|
||||
<p>The {@link android.print.pdf.PrintedPdfDocument} class uses a {@link android.graphics.Canvas}
|
||||
object to draw elements on an PDF page, similar to drawing on an activity layout. You can draw
|
||||
elements on the printed page using the {@link android.graphics.Canvas} draw methods. The following
|
||||
example code demonstrates how to draw some simple elements on a PDF document page using these
|
||||
methods:</p>
|
||||
|
||||
<pre>
|
||||
private void drawPage(PdfDocument.Page page) {
|
||||
Canvas canvas = page.getCanvas();
|
||||
|
||||
// units are in points (1/72 of an inch)
|
||||
int titleBaseLine = 72;
|
||||
int leftMargin = 54;
|
||||
|
||||
Paint paint = new Paint();
|
||||
paint.setColor(Color.BLACK);
|
||||
paint.setTextSize(36);
|
||||
canvas.drawText("Test Title", leftMargin, titleBaseLine, paint);
|
||||
|
||||
paint.setTextSize(11);
|
||||
canvas.drawText("Test paragraph", leftMargin, titleBaseLine + 25, paint);
|
||||
|
||||
paint.setColor(Color.BLUE);
|
||||
canvas.drawRect(100, 100, 172, 172, paint);
|
||||
}
|
||||
</pre>
|
||||
|
||||
<p>When using {@link android.graphics.Canvas} to draw on a PDF page, elements are specified in
|
||||
points, which is 1/72 of an inch. Make sure you use this unit of measure for specifying the size
|
||||
of elements on the page. For positioning of drawn elements, the coordinate system starts at 0,0
|
||||
for the top left corner of the page.</p>
|
||||
|
||||
<p>
|
||||
<strong>Tip:</strong> While the {@link android.graphics.Canvas} object allows you to place print
|
||||
elements on the edge of a PDF document, many printers are not able to print to the edge of a
|
||||
physical piece of paper. Make sure that you account for the unprintable edges of the page when
|
||||
you build a print document with this class.
|
||||
</p>
|
||||
175
docs/html/training/printing/html-docs.jd
Normal file
175
docs/html/training/printing/html-docs.jd
Normal file
@@ -0,0 +1,175 @@
|
||||
page.title=Printing HTML Documents
|
||||
parent.title=Printing Content
|
||||
parent.link=index.html
|
||||
|
||||
trainingnavtop=true
|
||||
next.title=Printing Custom Documents
|
||||
next.link=custom-docs.html
|
||||
|
||||
@jd:body
|
||||
|
||||
<div id="tb-wrapper">
|
||||
<div id="tb">
|
||||
|
||||
<h2>This lesson teaches you to</h2>
|
||||
<ol>
|
||||
<li><a href="#load-html">Load an HTML Document</a></li>
|
||||
<li><a href="#print-job">Create a Print Job</a></li>
|
||||
</ol>
|
||||
|
||||
</div>
|
||||
</div>
|
||||
|
||||
<p>Printing out content beyond a simple photo on Android requires composing text and graphics in a
|
||||
print document. The Android framework provides a way to use HTML to compose a document and
|
||||
print it with a minimum of code.</p>
|
||||
|
||||
<p>In Android 4.4 (API level 19), the {@link android.webkit.WebView} class has been updated to
|
||||
enable printing HTML content. The class allows you to load a local HTML resource or download
|
||||
a page from the web, create a print job and hand it off to Android's print services.</p>
|
||||
|
||||
<p>This lesson shows you how to quickly build an HTML document containing text and graphics and
|
||||
use {@link android.webkit.WebView} to print it.</p>
|
||||
|
||||
|
||||
<h2 id="load-html">Load an HTML Document</h2>
|
||||
|
||||
<p>Printing an HTML document with {@link android.webkit.WebView} involves loading an HTML
|
||||
resource or building an HTML document as a string. This section describes how to build an HTML
|
||||
string and load it into a {@link android.webkit.WebView} for printing.</p>
|
||||
|
||||
<p>This view object is typically used as part of an activity layout. However, if your application
|
||||
is not using a {@link android.webkit.WebView}, you can create an instance of the class
|
||||
specifically for printing purposes. The main steps for creating this custom print view are:</p>
|
||||
|
||||
<ol>
|
||||
<li>Create a {@link android.webkit.WebViewClient} that starts a print job after
|
||||
the HTML resource is loaded.</li>
|
||||
<li>Load the HTML resource into the {@link android.webkit.WebView} object.</li>
|
||||
</ol>
|
||||
|
||||
<p>The following code sample demonstrates how to create a simple {@link
|
||||
android.webkit.WebViewClient} and load an HTML document created on the fly:</p>
|
||||
|
||||
<pre>
|
||||
private WebView mWebView;
|
||||
|
||||
private void doWebViewPrint() {
|
||||
// Create a WebView object specifically for printing
|
||||
WebView webView = new WebView(getActivity());
|
||||
webView.setWebViewClient(new WebViewClient() {
|
||||
|
||||
public boolean shouldOverrideUrlLoading(WebView view, String url) {
|
||||
return false;
|
||||
}
|
||||
|
||||
@Override
|
||||
public void onPageFinished(WebView view, String url) {
|
||||
Log.i(TAG, "page finished loading " + url);
|
||||
createWebPrintJob(view);
|
||||
mWebView = null;
|
||||
}
|
||||
});
|
||||
|
||||
// Generate an HTML document on the fly:
|
||||
String htmlDocument = "<html><body><h1>Test Content</h1><p>Testing, " +
|
||||
"testing, testing...</p></body></html>";
|
||||
webView.loadDataWithBaseURL(null, htmlDocument, "text/HTML", "UTF-8", null);
|
||||
|
||||
// Keep a reference to WebView object until you pass the PrintDocumentAdapter
|
||||
// to the PrintManager
|
||||
mWebView = webView;
|
||||
}
|
||||
</pre>
|
||||
|
||||
<p class="note">
|
||||
<strong>Note:</strong> Make sure your call for generating a print job happens in the {@link
|
||||
android.webkit.WebViewClient#onPageFinished onPageFinished()} method of the {@link
|
||||
android.webkit.WebViewClient} you created in the previous section. If you don't wait until page
|
||||
loading is finished, the print output may be incomplete or blank, or may fail completely.
|
||||
</p>
|
||||
|
||||
<p class="note">
|
||||
<strong>Note:</strong> The example code above holds an instance of the
|
||||
{@link android.webkit.WebView} object so that is it not garbage collected before the print job
|
||||
is created. Make sure you do the same in your own implementation, otherwise the print process
|
||||
may fail.
|
||||
</p>
|
||||
|
||||
<p>
|
||||
If you want to include graphics in the page, place the graphic files in the {@code assets/}
|
||||
directory of your project and specify a base URL in the first parameter of the
|
||||
{@link android.webkit.WebView#loadDataWithBaseURL loadDataWithBaseURL()} method, as shown in the
|
||||
following code example:
|
||||
</p>
|
||||
|
||||
<pre>
|
||||
webView.loadDataWithBaseURL("file:///android_asset/images/", htmlBody,
|
||||
"text/HTML", "UTF-8", null);
|
||||
</pre>
|
||||
|
||||
<p>You can also load a web page for printing by replacing the
|
||||
{@link android.webkit.WebView#loadDataWithBaseURL loadDataWithBaseURL()} method with
|
||||
{@link android.webkit.WebView#loadUrl loadUrl()} as shown below.</p>
|
||||
|
||||
<pre>
|
||||
// Print an existing web page (remember to request INTERNET permission!):
|
||||
webView.loadUrl("http://developer.android.com/about/index.html");
|
||||
</pre>
|
||||
|
||||
<p>When using {@link android.webkit.WebView} for creating print documents, you should be aware of
|
||||
the following limitations:</p>
|
||||
|
||||
<ul>
|
||||
<li>You cannot add headers or footers, including page numbers, to the document.</li>
|
||||
<li>The printing options for the HTML document do not include the ability to print page
|
||||
ranges, for example: Printing page 2 to 4 of a 10 page HTML document is not supported.</li>
|
||||
<li>An instance of {@link android.webkit.WebView} can only process one print job at a time.</li>
|
||||
<li>An HTML document containing CSS print attributes, such as landscape properties, is not
|
||||
supported.</li>
|
||||
<li>You cannot use JavaScript in a HTML document to trigger printing.</li>
|
||||
</ul>
|
||||
|
||||
<p class="note">
|
||||
<strong>Note:</strong> The content of a {@link android.webkit.WebView} object that is included in
|
||||
a layout can also be printed once it has loaded a document.
|
||||
</p>
|
||||
|
||||
<p>If you want to create a more customized print output and have complete control of the content
|
||||
draw on the printed page, jump to the next lesson:
|
||||
<a href="custom-docs.html">Printing a Custom Document</a> lesson.</p>
|
||||
|
||||
|
||||
<h2 id="print-job">Create a Print Job</h2>
|
||||
|
||||
<p>After creating a {@link android.webkit.WebView} and loading your HTML content, your
|
||||
application is almost done with its part of the printing process. The next steps are accessing
|
||||
the {@link android.print.PrintManager}, creating a print adapter, and finally, creating a print
|
||||
job. The following example illustrates how to perform these steps:</p>
|
||||
|
||||
<pre>
|
||||
private void createWebPrintJob(WebView webView) {
|
||||
|
||||
// Get a PrintManager instance
|
||||
PrintManager printManager = (PrintManager) getActivity()
|
||||
.getSystemService(Context.PRINT_SERVICE);
|
||||
|
||||
// Get a print adapter instance
|
||||
PrintDocumentAdapter printAdapter = webView.createPrintDocumentAdapter();
|
||||
|
||||
// Create a print job with name and adapter instance
|
||||
String jobName = getString(R.string.app_name) + " Document";
|
||||
PrintJob printJob = printManager.print(jobName, printAdapter,
|
||||
new PrintAttributes.Builder().build());
|
||||
|
||||
// Save the job object for later status checking
|
||||
mPrintJobs.add(printJob);
|
||||
}
|
||||
</pre>
|
||||
|
||||
<p>This example saves an instance of the {@link android.print.PrintJob} object for use by the
|
||||
application, which is not required. Your application may use this object to track the progress of
|
||||
the print job as it's being processed. This approach is useful when you want to monitor the status
|
||||
of the print job in you application for completion, failure, or user cancellation. Creating an
|
||||
in-app notification is not required, because the print framework automatically creates a system
|
||||
notification for the print job.</p>
|
||||
57
docs/html/training/printing/index.jd
Normal file
57
docs/html/training/printing/index.jd
Normal file
@@ -0,0 +1,57 @@
|
||||
page.title=Printing Content
|
||||
page.tags="print","navigation","gesturedetector","scroller"
|
||||
|
||||
trainingnavtop=true
|
||||
startpage=true
|
||||
@jd:body
|
||||
|
||||
<div id="tb-wrapper">
|
||||
<div id="tb">
|
||||
|
||||
<h2>Dependencies and prerequisites</h2>
|
||||
|
||||
<ul>
|
||||
<li>Android 4.4 (API Level 19) or higher</li>
|
||||
</ul>
|
||||
|
||||
</div>
|
||||
</div>
|
||||
|
||||
<p>
|
||||
Android users frequently view content solely on their devices, but there are times when
|
||||
showing someone a screen is not an adequate way to share information. Being able to print
|
||||
information from your Android application gives users a way to see a larger version of the
|
||||
content from your app or share it with another person who is not using your application.
|
||||
Printing also allows them to create a snapshot of information that does not depend on having a
|
||||
device, sufficient battery power, or a wireless network connection.
|
||||
</p>
|
||||
|
||||
<p>
|
||||
In Android 4.4 (API level 19) and higher, the framework provides services for printing images and
|
||||
documents directly from Android applications. This training describes how to enable printing in
|
||||
your application, including printing images, HTML pages and creating custom documents for
|
||||
printing.
|
||||
</p>
|
||||
|
||||
|
||||
<h2>Lessons</h2>
|
||||
|
||||
<dl>
|
||||
<dt>
|
||||
<strong><a href="photos.html">Printing a Photo</a></strong>
|
||||
</dt>
|
||||
<dd>This lesson shows you how to print an image.</dd>
|
||||
|
||||
<dt>
|
||||
<strong><a href="html-docs.html">Printing an HTML Document</a></strong>
|
||||
</dt>
|
||||
<dd>This lesson shows you how to print an HTML document.</dd>
|
||||
|
||||
<dt>
|
||||
<strong><a href="custom-docs.html">Printing a Custom Document</a></strong>
|
||||
</dt>
|
||||
<dd>This lesson shows you how you connect to the Android print manager, create a print adapter
|
||||
and build content for printing.</dd>
|
||||
</dl>
|
||||
|
||||
|
||||
84
docs/html/training/printing/photos.jd
Normal file
84
docs/html/training/printing/photos.jd
Normal file
@@ -0,0 +1,84 @@
|
||||
page.title=Printing Photos
|
||||
parent.title=Printing Content
|
||||
parent.link=index.html
|
||||
|
||||
trainingnavtop=true
|
||||
next.title=Printing HTML Documents
|
||||
next.link=html-docs.html
|
||||
|
||||
@jd:body
|
||||
|
||||
<div id="tb-wrapper">
|
||||
<div id="tb">
|
||||
|
||||
<h2>This lesson teaches you to</h2>
|
||||
<ol>
|
||||
<li><a href="#image">Print an Image</a></li>
|
||||
</ol>
|
||||
|
||||
</div>
|
||||
</div>
|
||||
|
||||
<p>
|
||||
Taking and sharing photos is one of the most popular uses for mobile devices. If your application
|
||||
takes photos, displays them, or allows users to share images, you should consider enabling printing
|
||||
of those images in your application. The <a href="{@docRoot}tools/support-library/index.html"
|
||||
>Android Support Library</a> provides a convenient function for enabling image printing using a
|
||||
minimal amount of code and simple set of print layout options.
|
||||
</p>
|
||||
|
||||
<p>This lesson shows you how to print an image using the v4 support library {@link
|
||||
android.support.v4.print.PrintHelper} class.</p>
|
||||
|
||||
|
||||
<h2 id="image">Print an Image</h2>
|
||||
|
||||
<p>The Android Support Library {@link android.support.v4.print.PrintHelper} class provides
|
||||
a simple way to print of images. The class has a single layout option, {@link
|
||||
android.support.v4.print.PrintHelper#setScaleMode setScaleMode()}, which allows you to print with
|
||||
one of two options:</p>
|
||||
|
||||
<ul>
|
||||
<li>{@link android.support.v4.print.PrintHelper#SCALE_MODE_FIT SCALE_MODE_FIT} - This
|
||||
option sizes the image so that the whole image is shown within the printable area of the page.
|
||||
</li>
|
||||
<li>{@link android.support.v4.print.PrintHelper#SCALE_MODE_FILL SCALE_MODE_FILL} - This
|
||||
option scales the image so that it fills the entire printable area of the page. Choosing this
|
||||
setting means that some portion of the top and bottom, or left and right edges of the image is
|
||||
not printed. This option is the default value if you do not set a scale mode.</li>
|
||||
</ul>
|
||||
|
||||
<p>Both scaling options for {@link android.support.v4.print.PrintHelper#setScaleMode
|
||||
setScaleMode()} keep the existing aspect ratio of the image intact. The following code example
|
||||
shows how to create an instance of the {@link android.support.v4.print.PrintHelper} class, set the
|
||||
scaling option, and start the printing process:</p>
|
||||
|
||||
<pre>
|
||||
private void doPhotoPrint() {
|
||||
PrintHelper photoPrinter = new PrintHelper(getActivity());
|
||||
photoPrinter.setScaleMode(PrintHelper.SCALE_MODE_FIT);
|
||||
Bitmap bitmap = BitmapFactory.decodeResource(getResources(),
|
||||
R.drawable.droids);
|
||||
photoPrinter.printBitmap("droids.jpg - test print", bitmap);
|
||||
}
|
||||
</pre>
|
||||
|
||||
<p>
|
||||
This method can be called as the action for a menu item. Note that menu items for actions that are
|
||||
not always supported (such as printing) should be placed in the overflow menu. For more
|
||||
information, see the <a href="{@docRoot}design/patterns/actionbar.html">Action Bar</a> design
|
||||
guide.
|
||||
</p>
|
||||
|
||||
<p>After the {@link android.support.v4.print.PrintHelper#printBitmap printBitmap()} method is
|
||||
called, no further action from your application is required. The Android print user interface
|
||||
appears, allowing the user to select a printer and printing options. The user can then print the
|
||||
image or cancel the action. If the user chooses to print the image, a print job is created and a
|
||||
printing notification appears in the system bar.</p>
|
||||
|
||||
<p>If you want to include additional content in your printouts beyond just an image, you must
|
||||
construct a print document. For information on creating documents for printing, see the
|
||||
<a href="html-docs.html">Printing an HTML Document</a> or
|
||||
<a href="custom-docs.html">Printing a Custom Document</a>
|
||||
lessons.</p>
|
||||
|
||||
@@ -335,6 +335,30 @@ include the action bar on devices running Android 2.1 or higher."
|
||||
</li>
|
||||
</ul>
|
||||
</li>
|
||||
|
||||
<li class="nav-section">
|
||||
<div class="nav-section-header">
|
||||
<a href="<?cs var:toroot ?>training/printing/index.html"
|
||||
description=
|
||||
"How to print photos, HTML documents, and custom documents from your app."
|
||||
>Printing Content</a>
|
||||
</div>
|
||||
<ul>
|
||||
<li><a href="<?cs var:toroot ?>training/printing/photos.html">
|
||||
Photos
|
||||
</a>
|
||||
</li>
|
||||
<li><a href="<?cs var:toroot ?>training/printing/html-docs.html">
|
||||
HTML Documents
|
||||
</a>
|
||||
</li>
|
||||
<li><a href="<?cs var:toroot ?>training/printing/custom-docs.html">
|
||||
Custom Documents
|
||||
</a>
|
||||
</li>
|
||||
</ul>
|
||||
</li>
|
||||
|
||||
</ul>
|
||||
</li>
|
||||
<!-- End multimedia -->
|
||||
|
||||
Reference in New Issue
Block a user