Using multitouch and sensors in Java
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This document discusses using multi-touch and sensors in Java applications. It introduces JavaFX for touch support in Java and using JNI to access sensors from Java. It outlines the touch events and gestures supported in JavaFX. It also lists common sensors available on ultrabooks like accelerometers, gyroscopes, and GPS. It provides an overview of the Windows sensor APIs and how to use JNI to call native C++ methods to handle sensor events from Java.
![Using JNI to access the sensors from
Windows.Sensors
1. [Java] Create a native method to register the object that will
handle the events that come from the sensor
2. Generate the header file using javah
3. [C++] Create a DLL Project in Visual Studio with the DLLs
and namespaces of the Windows 8 APIS
4. [C++] Use a variable to keep a reference to the object and
the ID (GetMethodID) of the method that will handle the
event
17](https://image.slidesharecdn.com/usingmultitouchandsensorsinjava-131122073547-phpapp01/85/Using-multitouch-and-sensors-in-Java-17-320.jpg)
![Using JNI to access the sensors from
Windows.Sensors
5. [C++] Initialize the sensor and delegate a C++ method to
handle the event
6. [C++] Redirect the delegate method call to the Java method
using the function CallVoidMethod with the following
parameters: the Java Object, the method ID and it’s
parameters
7. [Java] Handle the event!
A lot of text? Please, show me the code!
18](https://image.slidesharecdn.com/usingmultitouchandsensorsinjava-131122073547-phpapp01/85/Using-multitouch-and-sensors-in-Java-18-320.jpg)
Using multitouch and sensors in Java
- 1. Using multi-touch and sensors in Java Felipe Pedroso
- 2. Agenda • The future of PCs • JavaFX and Touch Support • Using JNI to work with sensors 2
- 3. Mobile Computing Lines are Blurring Smartphone Consumption Usages Tablet Ultrabook™ Convertible & Detachable Ultrabook™ Creation/Productivity Notebook
- 4. Reshaping the PC Experience Multi-Touch Accelerometer Ambient Light Sensor Ultrabook™ Compass GPS Gyroscope Near Field Communication Context Aware Sensors 4
- 5. OK, they have all those features… … but how can we implement them using Java?
- 6. To allow users to TOUCH my Java App... • Should I use... • AWT? • Swing? • SWT? • Actually, you can use them but... • They aren’t made for multi-touch (OK, there’s a way to do it) • You must optimize your UI controls to be more ‘touch friendly’ • So, how to do it in a simple and easy way? 6
- 7. 7
- 8. Actions supported • Touch events: Down, Move and Up • Tap (Down and Up) / Double tap • Drag and Drop (Down, Move and Up) • Hold • Gestures • Swipe: Up, Down, Left and Right • Zoom: Pinch / Spread • Rotate 8
- 9. What I need to do to manipulate components? • Your components must extend the Node class or any of its subclasses (StackPane, ImageView, etc) • Set the proper EventHandler to handle the action. 9
- 10. What I need to do to manipulate components? • Apply a transform to the component (Translation, Rotation and Scale): • Let’s dive into some code! 10
- 11. What about the sensors? JNI, I choose you!
- 12. Available sensors on Ultrabooks • Accelerometer • Proper acceleration in three axis (x, y, z) • Gyrometer • Device orientation • Magnetometer • Strenght and direction of magnetic fields • GPS (Global Positioning System) • Location and Time information • NFC • Near Field Communication • Ambient Light Sensor • Ambient Light Level 12
- 13. API Windows – Sensor Fusion 13
- 14. API Windows – Namespaces • Windows.Sensors.* Common sensors • • • • • • • Accelerometer Gyrometer Inclinometer OrientationSensor SimpleOrientationSensor Compass LightSensor • Windows.Devices.Geolocation GPS • Geolocator • Windows.Networking.Proximity NFC • ProximityDevice 14
- 15. Windows API – How to • Get the default object of your sensor using the GetDefault method • You can call the GetCurrentReading() to get the current value of the sensors or... • ... work with the ReadingChanged event • Set the attribute ReportInterval (please, respect the MinimumReportInterval to avoid problems) • Delegate a method to handle the event (something like setting a method as a listener) • Handle the event! • This procedure is valid only for sensors from Windows.Sensors namespace 15
- 16. How can I access that? 16
- 17. Using JNI to access the sensors from Windows.Sensors 1. [Java] Create a native method to register the object that will handle the events that come from the sensor 2. Generate the header file using javah 3. [C++] Create a DLL Project in Visual Studio with the DLLs and namespaces of the Windows 8 APIS 4. [C++] Use a variable to keep a reference to the object and the ID (GetMethodID) of the method that will handle the event 17
- 18. Using JNI to access the sensors from Windows.Sensors 5. [C++] Initialize the sensor and delegate a C++ method to handle the event 6. [C++] Redirect the delegate method call to the Java method using the function CallVoidMethod with the following parameters: the Java Object, the method ID and it’s parameters 7. [Java] Handle the event! A lot of text? Please, show me the code! 18
- 19. What about Linux? • Touch works fine, but there aren’t clear APIs to read sensors. If you know how to do it, let’s work together! 19
- 20. Wants to know more about Intel Software? http://software.intel.com/pt-br/ 20
- 23. JFXtras.org 23
- 24. Take aways • The PC experience is being reshaped • JavaFX + Touch = AWESOME • Using JNI to access the sensors can be LEGENDARY!
- 25. Any doubts? (if yes, the answer is 42)
- 26. Thanks a lot! Felipe Pedroso facebook.com/felipe.a.pedroso @felipeapedroso