Small tablets, such as the 7-inch Samsung Galaxy Tab 2, offer some unique use cases and challenges. Whereas all the previous devices were mostly used in a vertical (portrait) orientation, tablets are more often rotated, doubling the com-plexity of the interface (see Figure 3.4).
Figure 3.4: The 7-inch Samsung Galaxy Tab 2 is an example of a small tablet device.
Android Device Trends49
As the hot zone picture in Figure 3.5 shows, in a vertical orientation, most small tablets are held with one hand, with the second hand tapping the controls. On the other hand (literally) in the horizontal (landscape) orientation, the device is most often held in a committed two-handed grip.
Figure 3.5: Small tablets dictate different hot zones for one-handed vertical, two-handed vertical, and two handed horizon-tal orientations.
Why this distinction? Holding the device in horizontal orientation in one hand is simply more difficult than holding the same device vertically in one hand. (Really, try it!) It has to do with a center of gravity of the device and where the center of gravity is located with respect to the fingers and the wrist. This is a simple physi-ological reality and is not likely to change any time soon: The fundamentals such as device weight, dimensions, and materials must change first.
What does all this mean from the standpoint of the interface design? There is enough space on the small tablet device to show one or more action bars comfort-ably. Looking at the hot zone in Figure 3.5, on small tablets in vertical orienta-tion, the entire top and bottom action bars are easily accessible, with the top bar being slightly more so. Thus Android guidelines can be followed as-is, and there is no need for measures like immersive navigation. Swiss-Army-Knife naviga-tion measures can lead to less satisfying experiences on tablets because they hide essential functions and force customers to learn where they are, which can cause cognitive friction. This guideline does not apply to immersive tasks such as reading and gaming, which traditionally use lights-out navigation, but to more navigation-centric tasks such as shopping.
One size definitely does not fit all! In general, it’s a good idea to make an effort to avoid cognitive friction for tablets, where the best interfaces keep customers
Chapter 3: android Fragmentation50
in a state of flow, offering simple, intuitive functions and wide, sweeping ges-tures (such as swiping to turn the page) that come naturally with the larger touch device. The C-Swipe gesture can be used for either the hand that is holding the device, or the hand that does the tapping, but chances are that the C-Swipe will happen in the middle of the device, or near the top portion of the screen, not on the bottom as it would for a one-handed grip on the mobile phones.
Things might be a little different in the horizontal orientation, which calls for a committed two-handed grip. Most of the navigation functionality is accessed using thumbs, while the rest of the fingers rest on the back of the device. Fortunately, most of the screen surface area, (including the essential Android back button) is easily accessible with average thumbs on a small tablet with a two-handed grip.
Thus again the Android guidelines can be used out-of-the-box; actually, they seem to be developed especially for small tablets!
Which is the preferred orientation? This question is difficult to answer, and most often no clear distinction can be drawn, even for specific tasks. From doing research and hours of field observations, people tend to read mostly with the device in a vertical orientation, where the interface forms a single column. On the other hand, the keyboard in vertical orientation does not offer the greatest experience—most people tend to rotate to horizontal when needing to use the keyboard-centered tasks such as filling out a form. Unfortunately, it is hard to see much of the form on a 7-inch tablet while the soft keyboard is also shown on the screen, so the entire form interaction on 7-inch tablets tends to be a rather awkward shuffling from vertical for scrolling to horizontal for typing, which is a less than ideal situation. This problem and some creative solutions are covered in detail in Chapters 10 (“Data Entry”) and 11 (“Forms”).
Another unique quality of small tablets is that they are actually small enough and light enough to be both held and manipulated with one hand, albeit with lim-ited capability. Where you see this show up is in longer-term immersive activi-ties such as reading. The person may want to both hold the small tablet and flip pages without using the second hand. This works well for the right-handed grip near the middle of the tablet, especially if the tablet is also partially resting on the person's lap, table, or chair arm. This is in part due to the generous margin around the touch screen, which enables the grip to be solid without touching the screen. Unfortunately, the same is not the case for the left-handed grip; most book apps flip the pages backward when they are tapped on the left side of the screen. The solution is to put controls along the left and right side of the screen or use a C-Swipe gesture to call up the menu from anywhere, as discussed in Chapter 14.
Android Device Trends51
From what can be observed in the field, the entire one-handed grip-and-use approach is not the most solid use case for the Apple iPad mini. The margin around the screen is simply too small to enable a comfortable grip.
Finally, what actually defines the tablet as “small”? It is the quality of comfort-able accessibility of the entire screen by the target customer population, without letting go of the sides of the device, with a possible one-handed vertical grip-and-use hold that defines the tablet as “small.” When some of the screen becomes inaccessible or a tablet can no longer be held and used by the same hand, it can be classified as “large.”