Using sensors in java me apps on series 40
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Using sensors in java me apps on series 40

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This webinar will introduce you to the sensors embedded on Nokia Asha phones and how to use them in Java ME apps and games. The structure and usage of the Mobile Sensor API (JSR-256) will be covered. ...

This webinar will introduce you to the sensors embedded on Nokia Asha phones and how to use them in Java ME apps and games. The structure and usage of the Mobile Sensor API (JSR-256) will be covered.
Attila Csipa, technology wizard at Nokia in Tampere, Finland, will give you a short overview that will be followed by plenty of examples and live coding demos. He’ll use the Nokia IDE for Java™ ME (Eclipse-based) to show you how to build your code. He’ll also share best practices and user-experience recommendations based on the most common use cases.

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Using sensors in java me apps on series 40 Using sensors in java me apps on series 40 Presentation Transcript

  • USING ACCELEROMETERS AND OTHERSENSORS IN JAVA ME ON SERIES 40Attila Csipa [@achipa]Technology Wizard, Nokia 1 © 2012 Nokia Using accelerometers and other sensors in Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa
  • CONTENTS• Introduction – Platforms & Versions• Sensors – Physical vs virtual – JSR-256 – Measurables – Accelerometers – Usage – UI considerations – Performance – App Compatibility• Resources 2 © 2012 Nokia Using accelerometers and other sensors from Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa
  • PLATFORMSAPI Differences: bit.ly/S40Apis5th Ed., FP1 6th Ed., Lite 6th Ed. 6th Ed., FP1 DP 1.0 DP 1.1 Developer Platform 2.0 http://www.developer.nokia.com/Devices/Device_specifications/Comparison.xhtml?dev=Asha_306,Nokia_Asha_309,Asha_311 3 © 2012 Nokia Using accelerometers and other sensors from Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa
  • DP 2.0 – NEW APIS Full touch Sensors & Multipoint UI Orientation Touch APIs Gestures: Virtual ... Pinch Keyboard4 © 2012 Nokia Using accelerometers and other sensors from Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa
  • SENSORS Etymology Originated 1925–30 from sense + -or. Noun sensor (plural sensors) A device or organ that detects certain external stimuli and responds in a distinctive manner.5 © 2012 Nokia Using accelerometers and other sensors from Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa
  • SENSORS: PHYSICAL VS VIRTUAL• Physical sensors (physical values, g or m/s, mbar, etc) – Acceleration – Light – ...• Virtual sensors (combined or interpreted values, %, enum-s) – Battery level – Orientation –… 6 © 2012 Nokia Using accelerometers and other sensors from Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa
  • SENSORS: JSR-256 JSR page at http://bit.ly/VdZDlG• JSR 256 Sensor API – Generic: designed also for temperature, blood pressure, etc. – Support on Series40 from DP2.0 (Asha Full Touch) – Also available on Symbian (from S60 5th edition onwards)• Two packages javax.microedition.sensor (read information) javax.microedition.sensor.control (settings, start/stop)7 © 2012 Nokia Using accelerometers and other sensors from Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa
  • SENSORS: WHAT TO LOOK FOR• Currently supported – Battery Charge: 0 .. 100, charge percentage – Network Field Intensity: 0 .. 100, signal strength – Charger State: 0 .. 1, charger connected – Acceleration: –2g .. +2g, x / y / z axis – Double Tap: 1 .. 63, phone sides – Orientation: 0 .. 6, phone orientation8 © 2012 Nokia Using accelerometers and other sensors from Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa
  • SENSORS: ACCELEROMETERS ARE COOL• Enrich user interaction – Doesn’t suffer from finger size limits – Doesn’t suffer from screen size limits – Doesn’t interfere with what the user sees on the screen – Natural interaction• Ideal for games!9 © 2012 Nokia Using accelerometers and other sensors from Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa
  • SENSORS: UNDERSTANDING ACCELEROMETERS• Acceleration is CHANGE of the speed vector• Standstill normalized value is 1.0, why? GRAVITY• Nitpick - accelerometers measure translation not rotation• Rotation can still be measured indirectly (we measure gravity vector hopping from one axis to the other)10 © 2012 Nokia Using accelerometers and other sensors from Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa
  • Example:SENSORS: API AVAILABILITY Racer, aMaze• No System property for the API version? – Check Class availability – ClassNotFoundException? → API not supported // Virtual keyboard support try { // Check if class is available Class.forName("javamicroedition.sensor.SensorConnection"); // SensorManager.findSensors("acceleration", null); useSensors = true; } catch (ClassNotFoundException e) { // Class not available: -> no Sensor API support. useSensors = false; } catch (Exception e) { }11 © 2012 Nokia Using accelerometers and other sensors from Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa
  • Example: MovingBallSENSORS: USING THEM – ROLL YOUR OWN• Establish sensor connection // Find all acceleration sensors, the contextType is left undefined SensorInfo[] sensorInfos = SensorManager.findSensors("acceleration", null); // Find an acceleration sensor that returns double values for (int i = 0; i < sensorInfos.length; i++) { if (sensorInfos[i].getChannelInfos()[0].getDataType() == ChannelInfo.TYPE_DOUBLE) { accSensor = (SensorConnection) Connector.open(sensorInfos[i].getUrl()); } }• Check data in game loop // Use 1 as a buffer size to get exactly 1 value for each axis Data[] data = accSensor.getData(1); speedX = -data[0].getDoubleValues()[0]; // data[0] => x-axis speedY = data[1].getDoubleValues()[0]; // data[1] => y-axis12 © 2012 Nokia Using accelerometers and other sensors from Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa
  • SENSORS: USING THEM – COPY WITH PRIDE• Use the wrapping classes from Nokia Developer examples private void enableSensors() { if (accelerationProvider != null) { accelerationProvider.close(); } accelerationProvider = AccelerationProvider.getProvider( new AccelerationProvider.Listener() { public void dataReceived(double ax, double ay, double az) { if (isSensorTurning()) { tilt = (int) ay; } } }); if (accelerationProvider != null) { Main.sensorsSupported = true; } else { Main.sensorsSupported = false; } }13 © 2012 Nokia Using accelerometers and other sensors from Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa
  • SENSORS: UI CONSIDERATIONS• Calibrate! (see aMaze example)• Look for change, not particular values• Which axis is which (portrait vs landscape)• Anticipate noise in readings (average values if needed)• Don’t force accelerometer usage if it doesn’t add to the user experience14 © 2012 Nokia Using accelerometers and other sensors from Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa
  • SENSORS: PERFORMANCE• Filter (LimitCondition) for values you’re really interested in• Separate from mainloop – use Threads (see Cottage360 video and source)• Responsiveness is more critical than with keyboard input• Choose right frequency (is 100 reads/sec really needed?)15 © 2012 Nokia Using accelerometers and other sensors from Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa
  • COMPATIBILITY16 © 2012 Nokia Using accelerometers and other sensors from Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa
  • COMPATIBILITY? CODE CONSIDERATIONS• Source & binary compatible – xx years old Java ME apps run on full touch phones (and vice versa)!• Downwards compatibility – Check API support of target phones – Lowest common denominator: → Nokia Java SDK 2.0 compiled app runs on old phones17 © 2012 Nokia Using accelerometers and other sensors from Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa
  • COMPATIBILITY? USE-CASE CONSIDERATIONS• Input type – Sensors complementing buttons (universal) – Discrete input CAN be easier with buttons (f.ex Snake)! – Sensors complementing touch controls (touch&type) – Most common – Accelerometer only (no pre-DP2.0) – Rarer than you think, but possible! (f.ex wire loop game)18 © 2012 Nokia Using accelerometers and other sensors from Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa
  • DYNAMIC API USAGE• Single code base for different phones – Code that uses new APIs – Externalize to extra class – Check API support at runtime – Instantiate class if supported – Different methods for checking available19 © 2012 Nokia Using accelerometers and other sensors from Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa
  • RESOURCES & TIPS22 © 2012 Nokia Using accelerometers and other sensors from Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa
  • NOKIA IDE FOR JAVA ME Integrated SDK + Toolchain JAD Editor App Templates Device SDK Manager23 © 2012 Nokia Using accelerometers and other sensors from Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa
  • CODE EXAMPLES• Nokia IDE – Nokia Hub → Nokia Series 40 Code Examples• Online – bit.ly/JavaMeExamples• Emulator – Help → MIDlet Samples• Maps & LWUIT – C:NokiadevicesNokia_SDK_2_0_Javaplugins 24 © 2012 Nokia Using accelerometers and other sensors from Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa
  • CODE EXAMPLES SHOWN TODAY• Wiki• aMaze• Racer• Cottage360 (episode 19)25 © 2012 Nokia Using accelerometers and other sensors from Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa
  • GET STARTED• Overview – www.developer.nokia.com/Develop/Java/Getting_started/• Downloads – SDK: www.developer.nokia.com/Develop/Java/ – LWUIT: projects.developer.nokia.com/LWUIT_for_Series_40• Guides – Design & User Experience – Porting from Android – www.developer.nokia.com/Develop/Java/Documentation/ – Training Videos: www.developer.nokia.com/Develop/Java/Learning/ – Code Examples: www.developer.nokia.com/Develop/Java/Code_examples/27 © 2012 Nokia Using accelerometers and other sensors from Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa
  • THANK YOU! QUESTIONS?Want to learn more?www.developer.nokia.comAttila Csipa [@achipa]Technology Wizard, Nokia 28 © 2012 Nokia Using accelerometers and other sensors from Java ME on Series 40 v1.1 October 23, 2012 Attila Csipa