I’ve covered four prominent apps, but there are many others. The basic functionality of all Android PDF apps is fairly similar, but there are some useful and interesting differences in the peripheral options they support. Whether these are worth the time, effort and expense involved in seeking them out, only you as a user can decide.
Adobe Reader for Android
Adobe ported its popular free PDF reading platform across to the Android OS quite early. When I first tried this a couple of months ago, it was a very basic system with a limited set of options: zoom in and out, and swipe across pages. Since then it’s been greatly enhanced, with a search option, buttons for adding notes and annotations, and a Share option for posting documents to Dropbox, email or Skype. As with the PC version, the user can view the document in three ways: one page at a time; as a continuous scroll; or in ‘reflow’ mode, where the text is extracted and wrapped to fit the screen width.
I was impressed by its progress, but where Reader fell down for me was in left-to-right single page scrolling, which was a lot slower than the up-down approach used in continuous mode, and in the method of text selection used to apply highlights and underlining, which were less accurate than some of its competitors. And options to customise the app are virtually non-existent. But for the occasional perusal of PDFs, Reader will meet most users’ needs.
This is a popular and highly-rated app in the Google Play store, with a Lite version for $1.00 or thereabouts, and a full version for $2.99, which supports form annotations. The main advantage over Reader in its presentation is a set of page thumbnails appearing along the base of the screen which give the user some idea of what’s coming next. These can also be laid out in a grid, like the Page view in Adobe Reader on PCs.
eZPDF has a built-in file explorer for locating files, and a much larger range of customisable settings. Like Adobe Reader, it supports reflowable text. There is a Night Mode, with white text on a black background, and an auto-page mode for hands-free reading.
The size of the comment/annotation toolbar and local menu items can be increased for users who are visually impaired, or just to make them easier to work with on a small screen, and the text-selection method is easier to use, involving a magnified section of the screen and circular ‘handles’ at the end of the range. Having made a set of annotations and/or highlights, the user can then save the annotated file under another name, and even export the annotation list as a separate text file.
Annotations can include images, including images taken with the tablet camera. Once an annotation is made, it can be edited or deleted by tapping it to select it, then double-tapping. Single-tapping brings up the text of comments.
The Repligo Reader falls squarely between the Lite and Full versions of eZPDF, with a cost of $1.99 for the ad-free version. It has a similar range of features to eZPDF, but the page thumbnails and annotation buttons are smaller and more difficult to use on a 7-inch screen, and there doesn’t appear to be a resize option.
The text-selection method for comments, highlighting and annotations is as good as, or perhaps slightly better than, eZPDF, but there’s no way to export annotations and notes as a text file. I couldn’t find a way to display the comments once they were entered, other than by selecting the comment icon and going back into Edit mode.
Mantano is a multipurpose reader which supports ePUB files as well as PDFs. It’s a little less user-friendly than either eZPDF or Repligo, but it has one first-rate feature which deserves to be widely copied: Once highlighting mode is turned on, it stays on from one page to the next, so a user can highlighting text while working through a document, and without jumping back and forth between modes.
A pop-up highlighting color panel appears in this mode, so different-colored highlights can be applied in sequence. The Premium version allows the user to browse through these highlights and other annotations, and to export them as a list.
I bought this one, priced at a hefty $8.96, because the text selection method is more accurate than in the cheaper versions: ‘Essentials’ for $3.86 and a Lite version for free. Since I highlight PDF documents for a living, amongst other things, it seemed like a good investment to me. But check the reviews before you buy. Many people love it; others have had problems.