The Google I/O developer conference was followed by the release of the official PDF reader for the Android mobile operating system of Google. The application has a simple and very effective feature set which allows viewing and navigating PDF files on Android devices.

The program was tested on an Evo 4G Smartphone made by HTC and powered by Android 2.1. The latest issue of Full Circle Magazine was used as a sample PDF, in order to make it possible to evaluate its performance by using relatively complex layouts. Initial load time seemed a bit longer than expected, when opening the PDF file from the download manager of the browser. Almost six seconds were necessary for the application to launch and render the document’s first page.

The user interface appears as simple and functional, although it is not consistent with the interface offered by other Android applications. Semi-transparent toolbars situated on the top and bottom of the screen fade out when not needed and give the user maximum viewing space possible during reading. Buttons for scroll and zoom are placed at the bottom toolbar, while the top toolbar displays the document title and is provided with a button allowing the user to switch the viewing mode.

Features

Multitouch pinch-zooming as well as flick-scrolling are supported by the application, but they were a bit slow during the test due to the overhead of content redrawing. Flick-scrolling is also occasionally slow while loading and drawing more content. If flick-scrolling is too fast, only blank sheets will appear instead of content of the pages. This makes it difficult to detect where you are in the document if you try to navigate faster.

Although this lag is somehow inconvenient during navigation, the reading experience is not affected. When the content is zoomed, the application is able to provide new rendered material fast enough to make reading comfortable and does not affect the pace of scrolling.

There is an alternate display mode, in addition to the standard one, in which the text is wrapped automatically, in order to fit the width of the screen. This alternate mode breaks down any element of the layouts and provides a solid stream of text that makes panning useless.

This display mode works fine with PDFs consisting mainly of formatted text with simpler layouts, such as e-books, and does not handle PDFs with intensive graphics. When in re flow mode, the zooming buttons of the toolbar situated on the bottom of the screen are replaced with a set of buttons that can be used to increase or decrease the font size.

Feasibility

The application runs properly and can support the kind of touch screen interaction expected by the users of modern mobile software. However, it is not a surprise that PDF rendering speed for a Smartphone is weak. The feature set, although sufficient, is modest, the main feature that is missing that supports searching.
The Adobe Reader for Android can be found in the Android market and is working on most devices running the Android 2.1 version or later. Adobe has performed tests on popular handsets like Google’s Nexus One or Motorola’s Android.