Gestures, Animations, Sensors in Android

Transcript

1. Gestures, Animations, Sensors in Android Orhan Obut © 2003–2014 Monitise Group Limited. All Rights Reserved. Confidential.
2. Agenda • Animation and Graphics • Animations in L • Gestures • Sensors
3. Animations • View Animation • Drawable Animation • Property Animation
4. View Animation • Older system and can only be used for Views • Easy to setup and offers enough capabilities to meet many application's needs. • Perform tweened animation on Views • A tween animation can perform a series of simple transformations (position, size, rotation, and transparency) • Defined by either XML or Android code • XML file is recommended because it's more readable, reusable, and swappable
5. View Animation <set> <scale Stretch /> <set> <scale Spin /> <rotate Rotate /> </set> </set>
7. Property Animation • Introduced in API Level 11 • Lets you animate properties of any object. • Extensible and lets you animate properties of custom types.
8. Create Property Animation • Create a ObjectAnimator • Set start and end values • Set duration • Start
9. Property Animation Code Snippet ObjectAnimator animator = ObjectAnimator.ofFloat(foo, TRANSLATION_X, 0f, 40f); animator.setDuration(40); animator.setTarget(View); animator.start();
11. Drawable Animation • Involves displaying Drawable resources one after another, like a roll of film. • Useful if you want to animate things that are easier to represent with Drawable resources, such as a progression of bitmaps.
12. Drawable Animation android:oneshot = false for infinite loop <animation-list android:oneshot="true"> <item drawable="@drawable/d1" android:duration="100" /> <item drawable="@drawable/d2" android:duration="100" /> <item drawable="@drawable/d3" android:duration="100" /> </animation-list> rocketImage.setBackgroundResource(R.drawable.hede);
14. Canvas and Drawables When drawing 2D graphics you have 2 options 1. Draw your graphics or animations into a View object from your layout. 2. Draw your graphics directly to a Canvas.
15. Draw on a View • Consider a custom view and use View.onDraw() when you do not need a significant amount of processing • Android framework will only call onDraw() as necessary. • Use invalidate() when you want to do redraw NOTE : Use postInvalidate() if you request from another thread other than main activity thread.
16. Draw with a Canvas When you would like to perform specialized drawing and/or control the animation of graphics, you should do so by drawing through a Canvas Bitmap b = Bitmap.createBitmap(100, 100, Bitmap.Config.ARGB_8888); Canvas c = new Canvas(b);
17. Draw on a SurfaceView • Special subclass of View that offers a dedicated drawing surface. • The aim is to use background thread, therefore the app isn't required to wait until the system's view hierarchy is ready to draw • Extend SurfaceView • Implement SurfaceHolder.Callback • Handle everything via a SurfaceHolder
19. Shape Drawable • Use ShapeDrawable when you want to dynamically draw 2D graphics. • You can programmatically draw primitive shapes and style. • You can also create shapes in XML and use them.
21. Nine-patch • Stretchable bitmap image • It must be saved with the extension .9. png and save into the res/drawable/ directory • Use Draw 9-patch tools (WYSIWYG)
23. OpenGL • Android supports OpenGL ES 1.0,2.0 and 3.0, with Android framework APIs as well as natively with the Native Development Kit (NDK).
24. Hardware Acceleration • Introduced in Android 3.0 (API level 11) • You can hardware accelerate the majority of the drawing done by the Canvas APIs to further increase their performance. • In manifest, add the following attribute <application android:hardwareAccelerated="true" ...>
25. Agenda • Animation and Graphics • Animations in L • Gestures • Sensors
26. • Touch Feedback • Reveal Effect • Activity Transitions • Curved Motion • Animating View State Changes • Drawable Tilting • Extracting Colors from an Image
27. Agenda • Animation and Graphics • Animations in L • Gestures • Sensors
28. Gestures • One or more fingers touch the screen • Interpret the pattern • Gesture has 2 phases : o Gather data o Interpret data
29. Gather Data • Override onTouchEvent() to intercept touch events. @Override public boolean onTouchEvent(MotionEvent event) { }
30. Interpret Data • Use GestureDetector class for common gestures • Use GestureOverlayView for gesture signatures • Use ScaleGestureDetector for scale • Use your own custom pattern if not enough
31. Gestures • Fling • Double Tap • Single Tap • Down • Scroll • Scale (ScaleGestureDetector) • Signatures (GestureOverlayView)
32. Agenda • Animation and Graphics • Animations in L • Gestures • Sensors
33. Motion Sensors • Monitor the motion of device such as tilt, shake, rotation or swing • All of the motion sensors return multi-dimensional arrays of sensor values for each SensorEvent
34. Motion Sensors • Accelerometer • Gravity • Gyroscope • Linear accelerometer • Rotation vector sensor • Significant motion sensor • Step counter sensor (Kitkat) • Step detector sensor (Kitkat) Motion sensors by themselves are not typically used to monitor device position, but they can be used with other sensors
35. Motion Sensors Examples • Shake and tilt features • Control a car in a game • Control a ball in a game • Make a run or walk application
36. Position Sensors • Useful for determining device's physical position in the world's frame of reference. • Returns multidimensional array
37. Position Sensors • Geomagnetic field sensor • Game rotation vector (Exclude geomagnetic) • Geomagnetic rotation vector sensor (use magnetometer) • Orientation sensor (Deprecated in API 8) • Proximity sensor
38. Position Sensors Examples • When holding phone close to ear, screen goes off • Use them to control rotation • Use for a compass
39. Environment Sensors • Monitor various environmental properties. • Return a single sensor value for each data event.
40. Environment Sensors • Light • Pressure • Temperature • Humidity
41. Environment Sensors Examples • Use to calculate humidity and temperature • Use to determine light
42. References http://developer.android.com