参考： http://blog.csdn.net/assassin4824/archive/2011/05/30/6454923.aspx
http://blog.sina.com.cn/s/blog_4d142b550100s1sx.html
http://blog.csdn.net/xiaoxiaobian3310903/archive/2011/05/24/6443250.aspx
http://www.ibm.com/developerworks/cn/opensource/os-cn-android-anmt2/

ScrollLayout.java

Java代码
  1. packagecom.lp;
  2. importandroid.content.Context;
  3. importandroid.graphics.Canvas;
  4. importandroid.util.AttributeSet;
  5. importandroid.util.Log;
  6. importandroid.view.MotionEvent;
  7. importandroid.view.VelocityTracker;
  8. importandroid.view.View;
  9. importandroid.view.ViewConfiguration;
  10. importandroid.view.ViewGroup;
  11. importandroid.widget.Scroller;
  12. /**
  13. *仿Launcher中的WorkSapce，可以左右滑动切换屏幕的类
  14. */
  15. publicclassScrollLayoutextendsViewGroup{
  16. privatestaticfinalStringTAG="ScrollLayout";
  17. privateScrollermScroller;
  18. privateVelocityTrackermVelocityTracker;
  20. privateintmCurScreen;
  21. privateintmDefaultScreen=0;
  23. privatestaticfinalintTOUCH_STATE_REST=0;
  24. privatestaticfinalintTOUCH_STATE_SCROLLING=1;
  26. privatestaticfinalintSNAP_VELOCITY=600;
  28. privateintmTouchState=TOUCH_STATE_REST;
  29. privateintmTouchSlop;
  30. privatefloatmLastMotionX;
  31. privatefloatmLastMotionY;
  32. publicScrollLayout(Contextcontext,AttributeSetattrs){
  33. this(context,attrs,0);
  34. //TODOAuto-generatedconstructorstub
  35. }
  36. publicScrollLayout(Contextcontext,AttributeSetattrs,intdefStyle){
  37. super(context,attrs,defStyle);
  38. //TODOAuto-generatedconstructorstub
  39. mScroller=newScroller(context);
  40. //默认显示第一屏
  41. mCurScreen=mDefaultScreen;
  42. mTouchSlop=ViewConfiguration.get(getContext()).getScaledTouchSlop();
  43. }
  44. @Override
  45. protectedvoidonLayout(booleanchanged,intl,intt,intr,intb){
  46. //TODOAuto-generatedmethodstub
  47. if(changed){
  48. intchildLeft=0;
  49. finalintchildCount=getChildCount();
  51. for(inti=0;i<childCount;i++){
  52. finalViewchildView=getChildAt(i);
  53. if(childView.getVisibility()!=View.GONE){
  54. finalintchildWidth=childView.getMeasuredWidth();
  55. childView.layout(childLeft,0,
  56. childLeft+childWidth,childView.getMeasuredHeight());
  57. childLeft+=childWidth;
  58. //很明显0-320|320-640|640-960...（假设屏幕宽320）
  59. }
  60. }
  61. }
  62. }
  63. @Override
  64. protectedvoidonMeasure(intwidthMeasureSpec,intheightMeasureSpec){
  65. Log.e(TAG,"onMeasure");
  66. super.onMeasure(widthMeasureSpec,heightMeasureSpec);
  68. finalintwidth=MeasureSpec.getSize(widthMeasureSpec);
  69. finalintwidthMode=MeasureSpec.getMode(widthMeasureSpec);
  70. if(widthMode!=MeasureSpec.EXACTLY){
  71. thrownewIllegalStateException("ScrollLayoutonlycanmCurScreenrunatEXACTLYmode!");
  72. }
  74. finalintheightMode=MeasureSpec.getMode(heightMeasureSpec);
  75. if(heightMode!=MeasureSpec.EXACTLY){
  76. thrownewIllegalStateException("ScrollLayoutonlycanrunatEXACTLYmode!");
  77. }
  79. //ThechildrenaregiventhesamewidthandheightasthescrollLayout
  80. finalintcount=getChildCount();
  81. for(inti=0;i<count;i++){
  82. getChildAt(i).measure(widthMeasureSpec,heightMeasureSpec);
  83. }
  84. //Log.e(TAG,"movingtoscreen"+mCurScreen);
  85. //x坐标y坐标
  86. //移动到第几屏
  87. scrollTo(mCurScreen*width,0);
  88. }
  90. /**
  91. *Accordingtothepositionofcurrentlayout
  92. *scrolltothedestinationpage.
  93. *判断滑动的位置
  94. *如果大于当前屏中间的位置则换屏
  95. *否则仍然是这个屏
  96. *getScrollXx方向的偏移量
  97. */
  99. publicvoidsnapToDestination(){
  100. finalintscreenWidth=getWidth();
  101. //判断
  102. finalintdestScreen=(getScrollX()+screenWidth/2)/screenWidth;
  103. snapToScreen(destScreen);
  104. }
  106. publicvoidsnapToScreen(intwhichScreen){
  107. //getthevalidlayoutpage
  108. whichScreen=Math.max(0,Math.min(whichScreen,getChildCount()-1));
  109. if(getScrollX()!=(whichScreen*getWidth())){
  111. finalintdelta=whichScreen*getWidth()-getScrollX();
  112. //开始滚动
  113. //x，y，x方向移动量，y方向移动量，滚动持续时间，负数往左滚
  114. mScroller.startScroll(getScrollX(),0,
  115. delta,0,Math.abs(delta)*2);
  116. mCurScreen=whichScreen;
  117. invalidate();//Redrawthelayout
  118. }
  119. }
  121. publicvoidsetToScreen(intwhichScreen){
  122. whichScreen=Math.max(0,Math.min(whichScreen,getChildCount()-1));
  123. mCurScreen=whichScreen;
  124. scrollTo(whichScreen*getWidth(),0);
  125. }
  127. publicintgetCurScreen(){
  128. returnmCurScreen;
  129. }
  130. //只有当前LAYOUT中的某个CHILD导致SCROLL发生滚动，才会致使自己的COMPUTESCROLL被调用
  131. @Override
  132. publicvoidcomputeScroll(){
  133. //TODOAuto-generatedmethodstub
  134. Log.e(TAG,"computeScroll");
  135. //如果返回true，表示动画还没有结束
  136. //因为前面startScroll，所以只有在startScroll完成时才会为false
  137. if(mScroller.computeScrollOffset()){
  138. Log.e(TAG,mScroller.getCurrX()+"======"+mScroller.getCurrY());
  139. //产生了动画效果每次滚动一点
  140. scrollTo(mScroller.getCurrX(),mScroller.getCurrY());
  141. postInvalidate();
  142. }
  143. }
  144. @Override
  145. publicbooleanonTouchEvent(MotionEventevent){
  146. //TODOAuto-generatedmethodstub
  147. Log.e(TAG,"onTouchEventstart");
  148. if(mVelocityTracker==null){
  149. mVelocityTracker=VelocityTracker.obtain();
  150. }
  151. mVelocityTracker.addMovement(event);
  153. finalintaction=event.getAction();
  154. finalfloatx=event.getX();
  155. finalfloaty=event.getY();
  157. switch(action){
  158. caseMotionEvent.ACTION_DOWN:
  159. Log.e(TAG,"eventdown!"+mScroller.isFinished());
  160. //如果屏幕的滚动动画没有结束你就按下了就结束动画
  161. if(!mScroller.isFinished()){
  162. mScroller.abortAnimation();
  163. }
  164. mLastMotionX=x;
  165. break;
  167. caseMotionEvent.ACTION_MOVE:
  168. Log.e(TAG,"eventmove!");
  169. //取得偏移量
  170. intdeltaX=(int)(mLastMotionX-x);
  171. Log.e(TAG,"detaX:"+deltaX);
  172. mLastMotionX=x;
  173. //x方向的偏移量y方向的偏移量
  174. scrollBy(deltaX,0);
  175. break;
  177. caseMotionEvent.ACTION_UP:
  178. Log.e(TAG,"event:up");
  179. //if(mTouchState==TOUCH_STATE_SCROLLING){
  180. finalVelocityTrackervelocityTracker=mVelocityTracker;
  181. velocityTracker.computeCurrentVelocity(1000);
  182. intvelocityX=(int)velocityTracker.getXVelocity();
  183. Log.e(TAG,"velocityX:"+velocityX);
  185. if(velocityX>SNAP_VELOCITY&&mCurScreen>0){
  186. //Flingenoughtomoveleft
  187. Log.e(TAG,"snapleft");
  188. snapToScreen(mCurScreen-1);
  189. }elseif(velocityX<-SNAP_VELOCITY
  190. &&mCurScreen<getChildCount()-1){
  191. //Flingenoughtomoveright
  192. Log.e(TAG,"snapright");
  193. snapToScreen(mCurScreen+1);
  194. }else{
  195. //一般都掉用这个
  196. snapToDestination();
  197. }
  198. if(mVelocityTracker!=null){
  199. mVelocityTracker.recycle();
  200. mVelocityTracker=null;
  201. }
  202. //}
  203. mTouchState=TOUCH_STATE_REST;
  204. break;
  205. caseMotionEvent.ACTION_CANCEL:
  206. mTouchState=TOUCH_STATE_REST;
  207. break;
  208. }
  210. returntrue;
  211. }
  212. //这个感觉没什么作用不管true还是false都是会执行onTouchEvent的因为子view里面onTouchEvent返回false了
  213. @Override
  214. publicbooleanonInterceptTouchEvent(MotionEventev){
  215. //TODOAuto-generatedmethodstub
  216. Log.e(TAG,"onInterceptTouchEvent-slop:"+mTouchSlop);
  218. finalintaction=ev.getAction();
  219. if((action==MotionEvent.ACTION_MOVE)&&
  220. (mTouchState!=TOUCH_STATE_REST)){
  221. returntrue;
  222. }
  224. finalfloatx=ev.getX();
  225. finalfloaty=ev.getY();
  227. switch(action){
  228. caseMotionEvent.ACTION_MOVE:
  229. Log.e(TAG,"onInterceptTouchEventmove");
  230. finalintxDiff=(int)Math.abs(mLastMotionX-x);
  231. if(xDiff>mTouchSlop){
  232. mTouchState=TOUCH_STATE_SCROLLING;
  234. }
  235. break;
  237. caseMotionEvent.ACTION_DOWN:
  238. Log.e(TAG,"onInterceptTouchEventdown");
  239. mLastMotionX=x;
  240. mLastMotionY=y;
  241. Log.e(TAG,mScroller.isFinished()+"");
  242. mTouchState=mScroller.isFinished()?TOUCH_STATE_REST:TOUCH_STATE_SCROLLING;
  243. break;
  245. caseMotionEvent.ACTION_CANCEL:
  246. caseMotionEvent.ACTION_UP:
  247. Log.e(TAG,"onInterceptTouchEventuporcancel");
  248. mTouchState=TOUCH_STATE_REST;
  249. break;
  250. }
  251. Log.e(TAG,mTouchState+"===="+TOUCH_STATE_REST);
  252. returnmTouchState!=TOUCH_STATE_REST;
  253. }
  255. }



main.xml

Java代码
  1. <?xmlversion="1.0"encoding="utf-8"?>
  2. <com.lp.ScrollLayout
  3. xmlns:android="http://schemas.android.com/apk/res/android"
  4. android:id="@+id/ScrollLayoutTest"
  5. android:layout_width="fill_parent"
  6. android:layout_height="fill_parent">
  7. <LinearLayout
  8. android:background="#FF00"
  9. android:layout_width="fill_parent"
  10. android:layout_height="fill_parent"></LinearLayout>
  12. <FrameLayout
  13. android:background="#F0F0"
  14. android:layout_width="fill_parent"
  15. android:layout_height="fill_parent"></FrameLayout>
  17. <FrameLayout
  18. android:background="#F00F"
  19. android:layout_width="fill_parent"
  20. android:layout_height="fill_parent">
  21. </FrameLayout>
  23. <LinearLayout
  24. android:background="#FF00"
  25. android:layout_width="fill_parent"
  26. android:layout_height="fill_parent">
  27. <Button
  28. android:layout_width="wrap_content"
  29. android:layout_height="wrap_content"
  30. android:text="Button1"/>
  31. </LinearLayout>
  32. <LinearLayout
  33. android:layout_width="wrap_content"
  34. android:layout_height="wrap_content">
  35. <Button
  36. android:layout_width="wrap_content"
  37. android:layout_height="wrap_content"
  38. android:text="Button2"/>
  39. </LinearLayout>
  40. </com.lp.ScrollLayout>

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