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10 <!DOCTYPE concept |
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12 <concept id="GUID-056165A7-E8A1-4868-8051-9EC58C5A3342" xml:lang="en"><title>Usability |
12 <concept id="GUID-056165A7-E8A1-4868-8051-9EC58C5A3342" xml:lang="en"><title>Usability |
13 considerations</title><prolog><metadata><keywords/></metadata></prolog><conbody> |
13 considerations</title><prolog><metadata><keywords/></metadata></prolog><conbody> |
14 <section id="GUID-E4B60228-49E7-415D-AFF1-9E9B622D2197"> <p>All touch and |
14 <p>All touch and gestural interfaces have to appear competent and safe. The |
15 gestural interfaces have to appear competent and safe. The interface needs |
15 interface must appear such that it is not going to misuse users' personal |
16 to look as though it is not going to misuse users' personal data or break |
16 data or break down. Optimizing system performance is critical here. Low screen |
17 down. Optimizing system performance is critical here. Low screen refresh rate |
17 refresh rate and latent images do not give the impression of a trustworthy |
18 and latent images do not give the impression of a trustworthy touch UI. The |
18 touch UI. The use of touch screen and sensors may also increase battery consumption |
19 use of touch screen and sensors may also increase battery consumption of mobile |
19 of mobile devices.</p> |
20 devices.</p><note><p>Touch screens consume most power during touch operations, |
20 <note><p>Touch screens consume most power during touch operations, and reducing |
21 and reducing unnecessary user interaction can help increase power efficiency. |
21 unnecessary user interaction can help increase power efficiency. Specifically |
22 Specifically with resistive touch screens, avoiding excessively long touch |
22 with resistive touch screens, avoiding excessively long touch and drag user |
23 and drag user actions is recommended. The continuous touch event flow keeps |
23 actions is recommended. The continuous touch event flow keeps the CPU busy. |
24 the CPU busy. The screen lock turns off the touch completely. To learn more |
24 The screen lock turns off the touch completely. To learn more about both optimizing |
25 about both optimizing system performance and battery life in Symbian applications, |
25 system performance and battery life, see the <xref href="http://developer.symbian.org/wiki/index.php/Power_Management" scope="external">Power Management</xref> section at the Symbian Foundation.</p></note> |
26 see the <xref href="http://www.forum.nokia.com/main/resources/user_experience/power_management/" scope="external">Power Management</xref> section at Forum Nokia.</p></note><p>The |
26 <p>The best products predict the needs of their users and then fulfill those |
27 best products predict the needs of their users and then fulfill those needs |
27 needs in unexpectedly pleasing ways. Adaptive targets are one way to do this. |
28 in unexpectedly pleasing ways. Adaptive targets are one way to do this. Controls |
28 Controls that match the users actions well are another way devices can be |
29 that match the users actions well are another way devices can be clever.</p> <p><b>Interaction |
29 clever.</p> |
30 design</b></p><p>Use appropriate and simple interaction logic:</p><ul> |
30 <p><b>Interaction design</b></p> |
31 <li><p>Navigation and controls should be clear and meaningful to prevent mistakes: |
31 <p>Use appropriate and simple interaction logic:</p> |
32 strokes along the touch panel should produce a logical outcome. </p></li> |
32 <ul> |
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33 <li><p>Navigation and controls must be clear and meaningful to prevent mistakes: |
|
34 strokes along the touch panel must produce a logical outcome. </p></li> |
33 <li><p>The coolest interaction in the world is empty unless it has clear meaning |
35 <li><p>The coolest interaction in the world is empty unless it has clear meaning |
34 for the person performing it. When using indirect controls, the UI response |
36 for the person performing it. When using indirect controls, the UI response |
35 should relate to the action the user is performing. </p></li> |
37 must relate to the action the user is performing. </p></li> |
36 <li><p>Meaningful controls are easier to learn and remember. </p></li> |
38 <li><p>Meaningful controls are easier to learn and remember. </p></li> |
37 </ul> <p>Touch UI can employ direct or indirect controls, or a combination |
39 </ul> |
38 of both:</p><ul> |
40 <p>Touch UI can employ direct or indirect controls, or a combination of both:</p> |
|
41 <ul> |
39 <li><p>Direct controls allow users to simply tap the item they want to manipulate |
42 <li><p>Direct controls allow users to simply tap the item they want to manipulate |
40 right on the screen itself, move it, make it bigger, scroll it, and so on. |
43 right on the screen itself, move it, make it bigger, scroll it, and so on. |
41 For more information, see <xref href="GUID-CCE6DC36-625C-487C-9AD8-F1BF8E36080A.dita">UI |
44 For more information, see <xref href="GUID-CCE6DC36-625C-487C-9AD8-F1BF8E36080A.dita">UI |
42 components</xref> and <xref href="GUID-BB8B3A11-0BBC-4759-A7F4-A28C9E70573F.dita">Touch |
45 components</xref> and <xref href="GUID-BB8B3A11-0BBC-4759-A7F4-A28C9E70573F.dita">Touch |
43 support for common UI components</xref>. </p></li> |
46 support for common UI components</xref>. </p></li> |
44 <li><p>Indirect controls use some other means to manipulate an object, for |
47 <li><p>Indirect controls use some other means to manipulate an object, for |
45 example, shaking, tilting, flipping, waving and so on. For more information, |
48 example, shaking, tilting, flipping, waving and so on. For more information, |
46 see <xref href="GUID-AE979B97-5610-42F3-99A7-5A3D66D3C2E6.dita">Sensor interaction</xref>.</p></li> |
49 see <xref href="GUID-AE979B97-5610-42F3-99A7-5A3D66D3C2E6.dita">Sensor interaction</xref>.</p></li> |
47 <li><p>While the Symbian style provides for the use of scroll bars, it is |
50 <li><p>Although Symbian platform allows the use of scrollbars, it is common |
48 common to reverse the page scrolling orientation in applications such as browser. |
51 to reverse the page scrolling orientation in applications such as browser. |
49 In absence of scroll bars, users will flick or drag the page upwards rather |
52 In absence of scrollbars, users will flick or drag the page upwards rather |
50 than pull a scroller down to move the page up, that is, to scroll down. In |
53 than pull a scrollbar down to move the page up, that is, to scroll down. In |
51 this case, scroll bars are used as navigation indicators.</p></li> |
54 this case, scrollbars are used as navigation indicators.</p></li> |
52 </ul><fig id="GUID-604A80CE-CB23-45A9-BC29-A01395CD6A2F"> |
55 </ul> |
53 <image href="GUID-EE5937B6-9103-4711-B13B-06A62D56AF79_d0e72052_href.png" scale="60" placement="inline"/> |
56 <fig id="GUID-604A80CE-CB23-45A9-BC29-A01395CD6A2F"> |
54 </fig><p>Direct taps and strokes are far easier for the user to understand |
57 <image href="GUID-EE5937B6-9103-4711-B13B-06A62D56AF79_d0e102831_href.png" scale="60" placement="inline"/> |
55 and pick up than abstract, indirect ones. A single view should always employ |
58 </fig> |
56 only a few indirect strokes, so that the controls do not confuse the user. </p><p><b>Visual |
59 <p>Direct taps and strokes are far easier for the user to understand and pick |
57 design</b></p><p>On touch screens, it is important to make a clear distinction |
60 up than abstract, indirect ones. A single view must always employ only a few |
58 between touchable areas, and non-touchable areas, such as text. </p><ul> |
61 indirect strokes, so that the controls do not confuse the user. </p> |
59 <li><p>Borders, glow effects, or other indicators can be used to highlight |
62 <p><b>Visual design</b></p> |
60 the interaction. </p></li> |
63 <p>On touch screens, it is important to make a clear distinction between touchable |
61 <li><p>Note that theme design alone is not sufficient for indicating touch |
64 areas, and non-touchable areas, such as text. Borders, glow effects, or other |
62 functionality: where one theme may indicate touch, another may not.</p></li> |
65 indicators can be used to highlight the interaction.<note>Theme design alone |
63 </ul><p>See also:</p><ul> |
66 is not sufficient for indicating touch functionality, where one theme may |
64 <li><p><xref href="GUID-5486EFD3-4660-4C19-A007-286DE48F6EEF.dita">Scale and positioning |
67 indicate touch, another may not.</note></p> |
65 of controls</xref></p></li> |
68 <p>See also:</p> |
66 <li><p><xref href="GUID-3CA039D8-A74D-4C9E-B4F5-6E153C7F65A1.dita">Finger vs. stylus</xref></p></li> |
|
67 <li><p><xref href="GUID-7BFEEDF7-3DB8-42FF-9D7A-F98E536F7686.dita">Sensor interaction</xref></p></li> |
|
68 </ul> </section> |
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69 </conbody></concept> |
69 </conbody></concept> |