Scroller (4) for Android learning-layout of rebound after pulling

Scroller (4) for Android learning-layout of rebound after pulling

MainActivity is as follows:

Package cc. testscroller2; import android. OS. bundle; import android. app. activity;/*** Demo Description: * The layout that can be pulled and then rebounded. * similar to the pull-down refresh. ** references: * 1 http://gundumw100.iteye.com/blog/1884373 * 2 http://blog.csdn.net/gemmem/article/details/7321910 * 3 http://ipjmc.iteye.com/blog/1615828 * 4 http://blog.csdn.net/c_weibin/article/details/7438323 * 5 http://www.cnblogs.com/wanqieddy/archive/2012/05/05/2484534.html * 6 http://blog.csdn.net/hudashi/article/details/7353075 * Thank you very much */public class MainActivity extends Activity {@ Overrideprotected void onCreate (Bundle savedInstanceState) {super. onCreate (savedInstanceState); setContentView (R. layout. main );}}

BounceableLinearLayout is as follows:

Package cc. testscroller2; import android. content. context; import android. util. attributeSet; import android. view. gestureDetector; import android. view. motionEvent; import android. widget. linearLayout; import android. widget. scroller;/*** overall idea: * process the Touch event of the View, that is, rewrite the onTouchEvent () method: * When the finger is lifted, return it to the origin, and submit the rest to GestureDetector for processing. ** in GestureDetector, the focus is to override the onScroll () method. in this method, the * Y sliding distance is obtained, and then the mscroroller is set. startScroll () method, ready to slide. * refresh the invalidate () interface to execute the computeScroll () method (). * call the scrollTo () method in the computeScroll () method to achieve real sliding. ** Note: * 1 parameter of the scrollTo () method: * scrollTo (mScroller. getCurrX (), mScroller. getCurrY (); * and then call postInvalidate () to refresh. *** method Description: * 1 mScroller. getFinalX (Y) () * The final X (Y) offset as an absolute distance from the origin. * return the scroll end position (get the value of the current X (Y) Distance from the original position ). valid only for "fling" scrolling. * That is to say, this method is for the rolling end. ** direction of Parallelism: ** the distance in the X direction. The distance between positive numbers and negative numbers to the right * Y direction. The distance between positive numbers and negative numbers is ** 2 mScroller. getCurrX (Y) () * The new X offset as an absolute distance from the origin. * The new Y offset as an absolute distance from the origin. * returns the offset of the current scrolling X (Y) Direction * that is, this method is applicable to scrolling. ** orientation: ** the distance from X to left. The distance from a positive number to left and from a negative number to the right X to Y. The distance from a positive number to an upward number, and from a negative number to a downward ** 3 invalidate () and postInvalidate () difference * invalidate () is used in the UI thread itself; postInvalidate () is used in non-UI threads. * This is a common saying about network data. Further research is needed. ** 4 startScroll (int startX, int startY, int dx, int dy, int duration) * start position of the first and second parameters. Third, offset of the four scrolls; duration of the fifth parameter ***/public class BounceableLinearLayout extends LinearLayout {private Scroller mScroller; private GestureDetector mGestureDetector; public listener (Context context) {this (context, null );} public BounceableLinearLayout (Context context, AttributeSet attrs) {super (context, attrs); setClickable (true); setLongClickable (true); mScroller = new Scroller (context ); mGestureDetector = new GestureDetector (context, new GestureListenerImpl () ;}@ Override public void computeScroll () {if (mScroller. computescroloffset () {System. out. println ("computeScroll () --->" + "mScroller. getCurrX () = "+ mScroller. getCurrX () + "," + "mScroller. getCurrY () = "+ mScroller. getCurrY (); scrollTo (mScroller. getCurrX (), mScroller. getCurrY (); // You must execute postInvalidate () to call computeScroll () // actually, call invalidate () here; or postInvalidate ();} super. computeScroll () ;}@ Override public boolean onTouchEvent (MotionEvent event) {switch (event. getAction () {case MotionEvent. ACTION_UP: // return to the initial position when the finger is lifted (0, 0); break; default: // in other cases, hand it to GestureDetector for gesture processing return mGestureDetector. onTouchEvent (event);} return super. onTouchEvent (event);} class GestureListenerImpl implements GestureDetector. onGestureListener {@ Overridepublic boolean onDown (MotionEvent e) {return true;} @ Overridepublic void onShowPress (MotionEvent e) {}@ Overridepublic boolean onSingleTapUp (MotionEvent e) {return false ;} // control the pull margin: // int disY = (int) (distanceY-0.5)/2); // You can also directly call: // smoothScrollBy (0, (int) distanceY); @ Overridepublic boolean onScroll (MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {int disY = (int) (distanceY-0.5)/2 ); beginScroll (0, disY); return false;} public void onLongPress (MotionEvent e) {}@ Overridepublic boolean onFling (MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {return false ;}// scroll to the target location protected void prepareScroll (int fx, int fy) {int dx = fx-mScroller. getFinalX (); int dy = fy-mScroller. getFinalY (); beginScroll (dx, dy);} // you can specify the relative offset protected void beginScroll (int dx, int dy) {System. out. println ("smoothScrollBy () ---> dx =" + dx + ", dy =" + dy); // first, the starting position of the two parameters; third, the offset of the four rollbacks. startScroll (mScroller. getFinalX (), mScroller. getFinalY (), dx, dy); System. out. println ("smoothScrollBy () --->" + "mScroller. getFinalX () = "+ mScroller. getFinalX () + "," + "mScroller. getFinalY () = "+ mScroller. getFinalY (); // You must execute invalidate () to call computeScroll () invalidate ();}}

Main. xml is as follows: