Android自定义ViewGroup实现竖向引导界面

<com.example.verticallinearlayout.verticallinearlayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
 android:id="@+id/id_main_ly"
 android:layout_width="match_parent"
 android:layout_height="fill_parent"
 android:orientation="vertical"
 android:background="#fff" >
 
 <relativelayout
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  android:background="@drawable/w02" >
 
  <button
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:text="hello" />
 </relativelayout>
 
 <relativelayout
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  android:background="@drawable/w03" >
 
  <button
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:layout_centerinparent="true"
   android:background="#fff"
   android:text="hello" />
 </relativelayout>
 
 <relativelayout
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  android:background="@drawable/w04" >
 
  <button
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:layout_centerinparent="true"
   android:text="hello" />
 </relativelayout>
 
 <relativelayout
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  android:background="@drawable/w05" >
 
  <button
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:layout_centerinparent="true"
   android:text="hello" />
 </relativelayout>
 
</com.example.verticallinearlayout.verticallinearlayout>

package com.example.verticallinearlayout;
 
import android.content.context;
import android.util.attributeset;
import android.util.displaymetrics;
import android.util.log;
import android.view.motionevent;
import android.view.velocitytracker;
import android.view.view;
import android.view.viewgroup;
import android.view.windowmanager;
import android.widget.scroller;
 
public class verticallinearlayout extends viewgroup
{
 /**
 * 屏幕的高度
 */
 private int mscreenheight;
 /**
 * 手指按下时的getscrolly
 */
 private int mscrollstart;
 /**
 * 手指抬起时的getscrolly
 */
 private int mscrollend;
 /**
 * 记录移动时的y
 */
 private int mlasty;
 /**
 * 滚动的辅助类
 */
 private scroller mscroller;
 /**
 * 是否正在滚动
 */
 private boolean isscrolling;
 /**
 * 加速度检测
 */
 private velocitytracker mvelocitytracker;
 /**
 * 记录当前页
 */
 private int currentpage = 0;
 
 private onpagechangelistener monpagechangelistener;
 
 public verticallinearlayout(context context, attributeset attrs)
 {
 super(context, attrs);
 
 /**
 * 获得屏幕的高度
 */
 windowmanager wm = (windowmanager) context.getsystemservice(context.window_service);
 displaymetrics outmetrics = new displaymetrics();
 wm.getdefaultdisplay().getmetrics(outmetrics);
 mscreenheight = outmetrics.heightpixels;
 // 初始化
 mscroller = new scroller(context);
 }
 
 @override
 protected void onmeasure(int widthmeasurespec, int heightmeasurespec)
 {
 super.onmeasure(widthmeasurespec, heightmeasurespec);
 int count = getchildcount();
 for (int i = 0; i < count; ++i)
 {
 view childview = getchildat(i);
 measurechild(childview, widthmeasurespec,mscreenheight);
 }
 }
 
 @override
 protected void onlayout(boolean changed, int l, int t, int r, int b)
 {
 if (changed)
 {
 int childcount = getchildcount();
 // 设置主布局的高度
 marginlayoutparams lp = (marginlayoutparams) getlayoutparams();
 lp.height = mscreenheight * childcount;
 setlayoutparams(lp);
 
 for (int i = 0; i < childcount; i++)
 {
 view child = getchildat(i);
 if (child.getvisibility() != view.gone)
 {
  child.layout(l, i * mscreenheight, r, (i + 1) * mscreenheight);// 调用每个自布局的layout
 }
 }
 
 }
 
 }
 
 @override
 public boolean ontouchevent(motionevent event)
 {
 // 如果当前正在滚动，调用父类的ontouchevent
 if (isscrolling)
 return super.ontouchevent(event);
 
 int action = event.getaction();
 int y = (int) event.gety();
 
 obtainvelocity(event);
 switch (action)
 {
 case motionevent.action_down:
 
 mscrollstart = getscrolly();
 mlasty = y;
 break;
 case motionevent.action_move:
 
 if (!mscroller.isfinished())
 {
 mscroller.abortanimation();
 }
 
 int dy = mlasty - y;
 // 边界值检查
 int scrolly = getscrolly();
 // 已经到达顶端，下拉多少，就往上滚动多少
 if (dy < 0 && scrolly + dy < 0)
 {
 dy = -scrolly;
 }
 // 已经到达底部，上拉多少，就往下滚动多少
 if (dy > 0 && scrolly + dy > getheight() - mscreenheight)
 {
 dy = getheight() - mscreenheight - scrolly;
 }
 
 scrollby(0, dy);
 mlasty = y;
 break;
 case motionevent.action_up:
 
 mscrollend = getscrolly();
 
 int dscrolly = mscrollend - mscrollstart;
 
 if (wantscrolltonext())// 往上滑动
 {
 if (shouldscrolltonext())
 {
  mscroller.startscroll(0, getscrolly(), 0, mscreenheight - dscrolly);
 
 } else
 {
  mscroller.startscroll(0, getscrolly(), 0, -dscrolly);
 }
 
 }
 
 if (wantscrolltopre())// 往下滑动
 {
 if (shouldscrolltopre())
 {
  mscroller.startscroll(0, getscrolly(), 0, -mscreenheight - dscrolly);
 
 } else
 {
  mscroller.startscroll(0, getscrolly(), 0, -dscrolly);
 }
 }
 isscrolling = true;
 postinvalidate();
 recyclevelocity();
 break;
 }
 
 return true;
 }
 
 /**
 * 根据滚动距离判断是否能够滚动到下一页
 * 
 * @return
 */
 private boolean shouldscrolltonext()
 {
 return mscrollend - mscrollstart > mscreenheight / 2 || math.abs(getvelocity()) > 600;
 }
 
 /**
 * 根据用户滑动，判断用户的意图是否是滚动到下一页
 * 
 * @return
 */
 private boolean wantscrolltonext()
 {
 return mscrollend > mscrollstart;
 }
 
 /**
 * 根据滚动距离判断是否能够滚动到上一页
 * 
 * @return
 */
 private boolean shouldscrolltopre()
 {
 return -mscrollend + mscrollstart > mscreenheight / 2 || math.abs(getvelocity()) > 600;
 }
 
 /**
 * 根据用户滑动，判断用户的意图是否是滚动到上一页
 * 
 * @return
 */
 private boolean wantscrolltopre()
 {
 return mscrollend < mscrollstart;
 }
 
 @override
 public void computescroll()
 {
 super.computescroll();
 if (mscroller.computescrolloffset())
 {
 scrollto(0, mscroller.getcurry());
 postinvalidate();
 } else
 {
 
 int position = getscrolly() / mscreenheight;
 
 log.e("xxx", position + "," + currentpage);
 if (position != currentpage)
 {
 if (monpagechangelistener != null)
 {
  currentpage = position;
  monpagechangelistener.onpagechange(currentpage);
 }
 }
 
 isscrolling = false;
 }
 
 }
 
 /**
 * 获取y方向的加速度
 * 
 * @return
 */
 private int getvelocity()
 {
 mvelocitytracker.computecurrentvelocity(1000);
 return (int) mvelocitytracker.getyvelocity();
 }
 
 /**
 * 释放资源
 */
 private void recyclevelocity()
 {
 if (mvelocitytracker != null)
 {
 mvelocitytracker.recycle();
 mvelocitytracker = null;
 }
 }
 
 /**
 * 初始化加速度检测器
 * 
 * @param event
 */
 private void obtainvelocity(motionevent event)
 {
 if (mvelocitytracker == null)
 {
 mvelocitytracker = velocitytracker.obtain();
 }
 mvelocitytracker.addmovement(event);
 }
 
 /**
 * 设置回调接口
 * 
 * @param onpagechangelistener
 */
 public void setonpagechangelistener(onpagechangelistener onpagechangelistener)
 {
 monpagechangelistener = onpagechangelistener;
 }
 
 /**
 * 回调接口
 * 
 * @author zhy
 * 
 */
 public interface onpagechangelistener
 {
 void onpagechange(int currentpage);
 }
}

package com.example.verticallinearlayout;
 
import android.app.activity;
import android.os.bundle;
import android.widget.toast;
 
import com.example.verticallinearlayout.verticallinearlayout.onpagechangelistener;
 
public class mainactivity extends activity
{
 private verticallinearlayout mmianlayout;
 
 @override
 protected void oncreate(bundle savedinstancestate)
 {
 super.oncreate(savedinstancestate);
 setcontentview(r.layout.activity_main);
 
 mmianlayout = (verticallinearlayout) findviewbyid(r.id.id_main_ly);
 mmianlayout.setonpagechangelistener(new onpagechangelistener()
 {
 @override
 public void onpagechange(int currentpage)
 {
// mmianlayout.getchildat(currentpage);
 toast.maketext(mainactivity.this, "第"+(currentpage+1)+"页", toast.length_short).show();
 }
 });
 }
 
}