android多种滑动冲突的解决方案

一、前言

android 中解决滑动的方案有2种：外部拦截法 和内部拦截法。

滑动冲突也存在2种场景: 横竖滑动冲突、同向滑动冲突。

所以我就写了4个例子来学习如何解决滑动冲突的，这四个例子分别为: 外部拦截法解决横竖冲突、外部拦截法解决同向冲突、内部拦截法解决横竖冲突、内部拦截法解决同向冲突。

先上效果图：

二、实战

1、外部拦截法，解决横竖冲突

思路是，重写父控件的onintercepttouchevent方法，然后根据具体的需求，来决定父控件是否拦截事件。如果拦截返回返回true，不拦截返回false。如果父控件拦截了事件，则在父控件的ontouchevent进行相应的事件处理。

我的这个例子，是一个横向滑动的viewgroup里面包含了3个竖向滑动的listview。下面我附上代码，horizontalex.java：

/**
 * created by blueberry on 2016/6/20.
 *
 * 解决交错的滑动冲突
 *
 * 外部拦截法
 */
public class horizontalex extends viewgroup {

 private static final string tag = "horizontalex";

 private boolean isfirsttouch = true;
 private int childindex;
 private int childcount;
 private int lastxintercept, lastyintercept, lastx, lasty;

 private scroller mscroller;
 private velocitytracker mvelocitytracker;

 public horizontalex(context context) {
  super(context);
  init();
 }

 public horizontalex(context context, attributeset attrs) {
  super(context, attrs);
  init();
 }

 public horizontalex(context context, attributeset attrs, int defstyleattr) {
  super(context, attrs, defstyleattr);
  init();
 }

 private void init() {
  mscroller = new scroller(getcontext());
  mvelocitytracker = velocitytracker.obtain();
 }

 @override
 protected void onmeasure(int widthmeasurespec, int heightmeasurespec) {
  int width = measurespec.getsize(widthmeasurespec);
  int height = measurespec.getsize(heightmeasurespec);
  int widthmode = measurespec.getmode(widthmeasurespec);
  int heightmode = measurespec.getmode(heightmeasurespec);

  childcount = getchildcount();
  measurechildren(widthmeasurespec, heightmeasurespec);

  if (childcount == 0) {
   setmeasureddimension(0, 0);
  } else if (widthmode == measurespec.at_most && heightmode == measurespec.at_most) {
   width = childcount * getchildat(0).getmeasuredwidth();
   height = getchildat(0).getmeasuredheight();
   setmeasureddimension(width, height);
  } else if (widthmode == measurespec.at_most) {
   width = childcount * getchildat(0).getmeasuredwidth();
   setmeasureddimension(width, height);
  } else {
   height = getchildat(0).getmeasuredheight();
   setmeasureddimension(width, height);
  }
 }

 @override
 protected void onlayout(boolean changed, int l, int t, int r, int b) {
  int left = 0;
  for (int i = 0; i < getchildcount(); i++) {
   final view child = getchildat(i);
   child.layout(left + l, t, r + left, b);
   left += child.getmeasuredwidth();
  }
 }

 /**
  * 拦截事件
  * @param ev
  * @return
  */
 @override
 public boolean onintercepttouchevent(motionevent ev) {
  boolean intercepted = false;
  int x = (int) ev.getx();
  int y = (int) ev.gety();

  switch (ev.getaction()) {
   /*如果拦截了down事件,则子类不会拿到这个事件序列*/
   case motionevent.action_down:
    lastxintercept = x;
    lastyintercept = y;
    intercepted = false;
    if (!mscroller.isfinished()) {
     mscroller.abortanimation();
     intercepted = true;
    }
    break;
   case motionevent.action_move:
    final int deltax = x - lastxintercept;
    final int deltay = y - lastyintercept;
    /*根据条件判断是否拦截该事件*/
    if (math.abs(deltax) > math.abs(deltay)) {
     intercepted = true;
    } else {
     intercepted = false;
    }
    break;
   case motionevent.action_up:
    intercepted = false;
    break;

  }
  lastxintercept = x;
  lastyintercept = y;
  return intercepted;
 }


 @override
 public boolean ontouchevent(motionevent event) {
  int x = (int) event.getx();
  int y = (int) event.gety();
  mvelocitytracker.addmovement(event);
  viewconfiguration configuration = viewconfiguration.get(getcontext());
  switch (event.getaction()) {
   case motionevent.action_down:
    if (!mscroller.isfinished()) {
     mscroller.abortanimation();
    }
    break;
   case motionevent.action_move:
    /*因为这里父控件拿不到down事件，所以使用一个布尔值，
     当事件第一次来到父控件时，对lastx,lasty赋值*/
    if (isfirsttouch) {
     lastx = x;
     lasty = y;
     isfirsttouch = false;
    }
    final int deltax = x - lastx;
    scrollby(-deltax, 0);
    break;
   case motionevent.action_up:
    int scrollx = getscrollx();
    final int childwidth = getchildat(0).getwidth();
    mvelocitytracker.computecurrentvelocity(1000, configuration.getscaledmaximumflingvelocity());
    float xvelocity = mvelocitytracker.getxvelocity();
    if (math.abs(xvelocity) > configuration.getscaledminimumflingvelocity()) {
     childindex = xvelocity < 0 ? childindex + 1 : childindex - 1;
    } else {
     childindex = (scrollx + childwidth / 2) / childwidth;
    }
    childindex = math.min(getchildcount() - 1, math.max(childindex, 0));
    smoothscrollby(childindex * childwidth - scrollx, 0);
    mvelocitytracker.clear();
    isfirsttouch = true;
    break;
  }

  lastx = x;
  lasty = y;
  return true;
 }

 void smoothscrollby(int dx, int dy) {
  mscroller.startscroll(getscrollx(), getscrolly(), dx, dy, 500);
  invalidate();
 }

 @override
 public void computescroll() {
  if (mscroller.computescrolloffset()) {
   scrollto(mscroller.getcurrx(), mscroller.getcurry());
   invalidate();
  }
 }

 @override
 protected void ondetachedfromwindow() {
  super.ondetachedfromwindow();
  mvelocitytracker.recycle();
 }
}

调用代码：

@override
 public void showouthvdata(list<string> data1, list<string> data2, list<string> data3) {
  listview listview1 = new listview(getcontext());
  arrayadapter<string> adapter1 = new arrayadapter<string>(getcontext(), android.r.layout.simple_list_item_1, data1);
  listview1.setadapter(adapter1);

  listview listview2 = new listview(getcontext());
  arrayadapter<string> adapter2 = new arrayadapter<string>(getcontext(), android.r.layout.simple_list_item_1, data2);
  listview2.setadapter(adapter2);

  listview listview3 = new listview(getcontext());
  arrayadapter<string> adapter3 = new arrayadapter<string>(getcontext(), android.r.layout.simple_list_item_1, data3);
  listview3.setadapter(adapter3);

  viewgroup.layoutparams params
    = new viewgroup.layoutparams(viewgroup.layoutparams.match_parent,
    viewgroup.layoutparams.match_parent);

  mhorizontalex.addview(listview1, params);
  mhorizontalex.addview(listview2, params);
  mhorizontalex.addview(listview3, params);
 }

其实外部拦截的主要思想都在于对onintercepttouchevent的重写。

@override
 public boolean onintercepttouchevent(motionevent ev) {
  boolean intercepted = false;
  int x = (int) ev.getx();
  int y = (int) ev.gety();

  switch (ev.getaction()) {
   /*如果拦截了down事件,则子类不会拿到这个事件序列*/
   case motionevent.action_down:
    lastxintercept = x;
    lastyintercept = y;
    intercepted = false;
    if (!mscroller.isfinished()) {
     mscroller.abortanimation();
     intercepted = true;
    }
    break;
   case motionevent.action_move:
    final int deltax = x - lastxintercept;
    final int deltay = y - lastyintercept;
    /*根据条件判断是否拦截该事件*/
    if (math.abs(deltax) > math.abs(deltay)) {
     intercepted = true;
    } else {
     intercepted = false;
    }
    break;
   case motionevent.action_up:
    intercepted = false;
    break;

  }
  lastxintercept = x;
  lastyintercept = y;
  return intercepted;
 }

这几乎是一个实现外部拦截事件的模板，这里一定不要在action_down 中返回 true,否则会让子view没有机会得到事件，因为如果在action_down的时候返回了 true,同一个事件序列viewgroup的dispatchtouchevent就不会在调用onintercepttouchevent方法了。

还有就是 在action_up中返回false，因为如果父控件拦截了action_up，那么子view将得不到up事件，那么将会影响子view的 onclick方法等。但这对父控件是没有影响的，因为如果是父控件子aciton_move中 就拦截了事件，他们up事件必定也会交给它处理，因为有那么一条定律叫做：父控件一但拦截了事件，那么同一个事件序列的所有事件都将交给他处理。这条结论在我的上一篇文章中已经分析过。

最后就是在 action_move中根据需求决定是否拦截。

2、内部拦截法，解决横竖冲突

内部拦截主要依赖于父控件的 requestdisallowintercepttouchevent方法，关于这个方法我的上篇文章其实已经分析过。他设置父控件的一个标志（flag_disallow_intercept）

这个标志可以决定父控件是否拦截事件，如果设置了这个标志则不拦截，如果没设这个标志，它就会调用父控件的onintercepttouchevent（）来询问父控件是否拦截。但这个标志对down事件无效。

可以参考一下源码：   

 // handle an initial down.
   if (actionmasked == motionevent.action_down) {
    // throw away all previous state when starting a new touch gesture.
    // the framework may have dropped the up or cancel event for the previous gesture
    // due to an app switch, anr, or some other state change.
    cancelandcleartouchtargets(ev);
    //清楚标志
    resettouchstate();
   }

   // check for interception.
   final boolean intercepted;
   if (actionmasked == motionevent.action_down
     || mfirsttouchtarget != null) {
     //标志
    final boolean disallowintercept = (mgroupflags & flag_disallow_intercept) != 0;
    if (!disallowintercept) {
     intercepted = onintercepttouchevent(ev);
     ev.setaction(action); // restore action in case it was changed
    } else {
     intercepted = false;
    }
   } else {
    // there are no touch targets and this action is not an initial down
    // so this view group continues to intercept touches.
    intercepted = true;
   }

那么我们如果想使用 内部拦截法拦截事件。

第一步：

a、我们要重写父控件的onintercepttouchevent，在action_down的时候返回false,负责的话子view调用requestdisallowintercepttouchevent也将无能为力。

b、还有就是其他事件的话都返回true,这样就把能否拦截事件的权利交给了子view。

第二步:

在子view的dispatchtouchevent中 来决定是否让父控件拦截事件。

a. 先要在motionevent.action_down:的时候使用mhorizontalex2.requestdisallowintercepttouchevent(true);，负责的话，下一个事件到来时，就交给父控件了。

b. 然后在motionevent.action_move: 根据业务逻辑决定是否调用mhorizontalex2.requestdisallowintercepttouchevent(false);来决定父控件是否拦截事件。

上代码horizontalex2.java:

/**
 * created by blueberry on 2016/6/20.
 * 内部拦截
 * 和 listviewex配合使用
 */
public class horizontalex2 extends viewgroup {

 private int lastx, lasty;
 private int childindex;
 private scroller mscroller;
 private velocitytracker mvelocitytracker;

 public horizontalex2(context context) {
  super(context);
  init();
 }

 public horizontalex2(context context, attributeset attrs) {
  super(context, attrs);
  init();
 }

 public horizontalex2(context context, attributeset attrs, int defstyleattr) {
  super(context, attrs, defstyleattr);
  init();
 }

 private void init() {
  mscroller = new scroller(getcontext());
  mvelocitytracker = velocitytracker.obtain();
 }

 @override
 protected void onmeasure(int widthmeasurespec, int heightmeasurespec) {
  int width = measurespec.getsize(widthmeasurespec);
  int widthmode = measurespec.getmode(widthmeasurespec);
  int height = measurespec.getsize(heightmeasurespec);
  int heightmode = measurespec.getmode(heightmeasurespec);

  int childcount = getchildcount();
  measurechildren(widthmeasurespec, heightmeasurespec);

  if (childcount == 0) {
   setmeasureddimension(0, 0);
  } else if (widthmode == measurespec.at_most && heightmode == measurespec.at_most) {
   height = getchildat(0).getmeasuredheight();
   width = childcount * getchildat(0).getmeasuredwidth();
   setmeasureddimension(width, height);
  } else if (widthmode == measurespec.at_most) {
   width = childcount * getchildat(0).getmeasuredwidth();
   setmeasureddimension(width, height);
  } else {
   height = getchildat(0).getmeasuredheight();
   setmeasureddimension(width, height);
  }
 }

 @override
 protected void onlayout(boolean changed, int l, int t, int r, int b) {
  int leftoffset = 0;
  for (int i = 0; i < getchildcount(); i++) {
   view child = getchildat(i);
   child.layout(l + leftoffset, t, r + leftoffset, b);
   leftoffset += child.getmeasuredwidth();
  }
 }

 /**
  * 不拦截down事件，其他一律拦截
  * @param ev
  * @return
  */
 @override
 public boolean onintercepttouchevent(motionevent ev) {
  if (ev.getaction() == motionevent.action_down) {
   if (!mscroller.isfinished()) {
    mscroller.abortanimation();
    return true;
   }
   return false;
  } else {
   return true;
  }
 }

 private boolean isfirsttouch = true;

 @override
 public boolean ontouchevent(motionevent event) {
  int x = (int) event.getx();
  int y = (int) event.gety();
  mvelocitytracker.addmovement(event);
  viewconfiguration configuration = viewconfiguration.get(getcontext());
  switch (event.getaction()) {
   case motionevent.action_down:
    if (!mscroller.isfinished()) {
     mscroller.abortanimation();
    }
    break;
   case motionevent.action_move:
    if (isfirsttouch) {
     isfirsttouch = false;
     lasty = y;
     lastx = x;
    }
    final int deltax = x - lastx;
    scrollby(-deltax, 0);
    break;
   case motionevent.action_up:
    isfirsttouch = true;
    int scrollx = getscrollx();
    mvelocitytracker.computecurrentvelocity(1000, configuration.getscaledmaximumflingvelocity());
    float mvelocityx = mvelocitytracker.getxvelocity();
    if (math.abs(mvelocityx) > configuration.getscaledminimumflingvelocity()) {
     childindex = mvelocityx < 0 ? childindex + 1 : childindex - 1;
    } else {
     childindex = (scrollx + getchildat(0).getwidth() / 2) / getchildat(0).getwidth();
    }
    childindex = math.min(getchildcount() - 1, math.max(0, childindex));
    smoothscrollby(childindex*getchildat(0).getwidth()-scrollx,0);
    mvelocitytracker.clear();
    break;
  }

  lastx = x;
  lasty = y;
  return true;
 }

 private void smoothscrollby(int dx, int dy) {
  mscroller.startscroll(getscrollx(), getscrolly(), dx, dy,500);
  invalidate();
 }

 @override
 public void computescroll() {
  if(mscroller.computescrolloffset()){
   scrollto(mscroller.getcurrx(),mscroller.getcurry());
   postinvalidate();
  }
 }

 @override
 protected void ondetachedfromwindow() {
  super.ondetachedfromwindow();
  mvelocitytracker.recycle();
 }
}

listviewex.java

/**
 * 内部拦截事件
 */
public class listviewex extends listview {

 private int lastxintercepted, lastyintercepted;

 private horizontalex2 mhorizontalex2;

 public listviewex(context context) {
  super(context);
 }

 public listviewex(context context, attributeset attrs) {
  super(context, attrs);
 }

 public listviewex(context context, attributeset attrs, int defstyleattr) {
  super(context, attrs, defstyleattr);
 }

 public horizontalex2 getmhorizontalex2() {
  return mhorizontalex2;
 }

 public void setmhorizontalex2(horizontalex2 mhorizontalex2) {
  this.mhorizontalex2 = mhorizontalex2;
 }

 /**
  * 使用 outter.requestdisallowintercepttouchevent();
  * 来决定父控件是否对事件进行拦截
  * @param ev
  * @return
  */
 @override
 public boolean dispatchtouchevent(motionevent ev) {
  int x = (int) ev.getx();
  int y = (int) ev.gety();
  switch (ev.getaction()) {
   case motionevent.action_down:
    mhorizontalex2.requestdisallowintercepttouchevent(true);
    break;
   case motionevent.action_move:
    final int deltax = x-lastyintercepted;
    final int deltay = y-lastyintercepted;
    if(math.abs(deltax)>math.abs(deltay)){
     mhorizontalex2.requestdisallowintercepttouchevent(false);
    }
    break;
   case motionevent.action_up:
    break;
  }
  lastxintercepted = x;
  lastyintercepted = y;
  return super.dispatchtouchevent(ev);
 }
}

调用代码：

 @override
 public void showinnerhvdata(list<string> data1, list<string> data2, list<string> data3) {

  listviewex listview1 = new listviewex(getcontext());
  arrayadapter<string> adapter1 = new arrayadapter<string>(getcontext(), android.r.layout.simple_list_item_1, data1);
  listview1.setadapter(adapter1);
  listview1.setmhorizontalex2(mhorizontalex2);

  listviewex listview2 = new listviewex(getcontext());
  arrayadapter<string> adapter2 = new arrayadapter<string>(getcontext(), android.r.layout.simple_list_item_1, data2);
  listview2.setadapter(adapter2);
  listview2.setmhorizontalex2(mhorizontalex2);

  listviewex listview3 = new listviewex(getcontext());
  arrayadapter<string> adapter3 = new arrayadapter<string>(getcontext(), android.r.layout.simple_list_item_1, data3);
  listview3.setadapter(adapter3);
  listview3.setmhorizontalex2(mhorizontalex2);

  viewgroup.layoutparams params
    = new viewgroup.layoutparams(viewgroup.layoutparams.match_parent,
    viewgroup.layoutparams.match_parent);

  mhorizontalex2.addview(listview1, params);
  mhorizontalex2.addview(listview2, params);
  mhorizontalex2.addview(listview3, params);
 }

至此，2种拦截方法已经学习完毕，下面我们来学习如何解决同向滑动冲突。

其实和上面的2个例子思路是一样的，只是用来判断是否拦截的那块逻辑不同而已。

下面的例子，是一个下拉刷新的一个控件。

3、外部拦截 解决同向滑动冲突

refreshlayoutbase.java

package com.blueberry.sample.widget.refresh;

import android.content.context;
import android.graphics.color;
import android.util.attributeset;
import android.util.displaymetrics;
import android.util.log;
import android.util.typedvalue;
import android.view.motionevent;
import android.view.view;
import android.view.viewconfiguration;
import android.view.viewgroup;
import android.view.windowmanager;
import android.widget.progressbar;
import android.widget.scroller;
import android.widget.textview;

import com.blueberry.sample.r;

/**

 *外部拦截(同向)
 *
 */
public abstract class refreshlayoutbase<t extends view> extends viewgroup {

 private static final string tag = "refreshlayoutbase";

 public static final int status_loading = 1;
 public static final int status_release_to_refresh = 2;
 public static final int status_pull_to_refresh = 3;
 public static final int status_idle = 4;
 public static final int status_load_more =5;
 private static int scroll_duration =500;

 protected viewgroup mheadview;
 protected viewgroup mfootview;
 private t contentview;
 private progressbar headprogressbar;
 private textview headtv;
 private progressbar footprogressbar;
 private textview foottv;

 private boolean isfisttouch = true;

 protected int currentstatus = status_idle;
 private int mscreenwidth;
 private int mscreenheight;
 private int mlastxintercepted;
 private int mlastyintercepted;
 private int mlastx;
 private int mlasty;
 protected int minitscrolly = 0;
 private int mtouchslop;

 protected scroller mscoller;

 private onrefreshlistener monrefreshlistener;

 public refreshlayoutbase(context context) {
  this(context, null);
 }

 public refreshlayoutbase(context context, attributeset attrs) {
  this(context, attrs, 0);
 }

 public refreshlayoutbase(context context, attributeset attrs, int defstyleattr) {
  super(context, attrs, defstyleattr);
  getscreensize();
  initview();
  mscoller = new scroller(context);
  mtouchslop = viewconfiguration.get(context).getscaledtouchslop();
  setpadding(0, 0, 0, 0);
 }

 public void setcontentview(t view) {
  addview(view, 1);
 }

 public onrefreshlistener getonrefreshlistener() {
  return monrefreshlistener;
 }

 public void setonrefreshlistener(onrefreshlistener monrefreshlistener) {
  this.monrefreshlistener = monrefreshlistener;
 }

 private void initview() {
  setupheadview();
  setupfootview();
 }

 private void getscreensize() {
  windowmanager wm = (windowmanager) getcontext().getsystemservice(context.window_service);
  displaymetrics metrics = new displaymetrics();
  wm.getdefaultdisplay().getmetrics(metrics);
  mscreenwidth = metrics.widthpixels;
  mscreenheight = metrics.heightpixels;
 }

 private int dp2px(int dp) {
  windowmanager wm = (windowmanager) getcontext().getsystemservice(context.window_service);
  displaymetrics metrics = new displaymetrics();
  wm.getdefaultdisplay().getmetrics(metrics);
  return (int) typedvalue.applydimension(typedvalue.complex_unit_dip, dp, metrics);
 }

 /**
  * 设置头布局
  */
 private void setupheadview() {
  mheadview = (viewgroup) view.inflate(getcontext(), r.layout.fresh_head_view, null);
  mheadview.setbackgroundcolor(color.red);
  headprogressbar = (progressbar) mheadview.findviewbyid(r.id.head_progressbar);
  headtv = (textview) mheadview.findviewbyid(r.id.head_tv);
  /*设置 实际高度为 1/4 ，但内容区域只有 100dp*/
  viewgroup.layoutparams layoutparams = new viewgroup.layoutparams(layoutparams.match_parent, mscreenheight / 4);
  mheadview.setlayoutparams(layoutparams);
  mheadview.setpadding(0, mscreenheight / 4 - dp2px(100), 0, 0);
  addview(mheadview);
 }

 /**
  * 设置尾布局
  */
 private void setupfootview() {
  mfootview = (viewgroup) view.inflate(getcontext(), r.layout.fresh_foot_view, null);
  mfootview.setbackgroundcolor(color.blue);
  footprogressbar = (progressbar) mfootview.findviewbyid(r.id.fresh_foot_progressbar);
  foottv = (textview) mfootview.findviewbyid(r.id.fresh_foot_tv);
  addview(mfootview);
 }

 @override
 protected void onmeasure(int widthmeasurespec, int heightmeasurespec) {
  int widthsize = measurespec.getsize(widthmeasurespec);
  int widthmode = measurespec.getmode(widthmeasurespec);
  int height = measurespec.getsize(heightmeasurespec);
  int heightmode = measurespec.getmode(heightmeasurespec);

  int finalheight = 0;
  for (int i = 0; i < getchildcount(); i++) {
   view child = getchildat(i);
   measurechild(child, widthmeasurespec, heightmeasurespec);
   finalheight += child.getmeasuredheight();
  }

  if (widthmode == measurespec.at_most && heightmode == measurespec.at_most) {
   widthsize = getchildat(0).getmeasuredwidth();
   setmeasureddimension(widthsize, finalheight);
  } else if (widthmode == measurespec.at_most) {
   widthsize = getchildat(0).getmeasuredwidth();
   setmeasureddimension(widthsize, height);
  } else {
   setmeasureddimension(widthsize, finalheight);
  }

 }


 @override
 protected void onlayout(boolean changed, int l, int t, int r, int b) {
  int topoffset = 0;
  for (int i = 0; i < getchildcount(); i++) {
   view child = getchildat(i);
   child.layout(getpaddingleft(), getpaddingtop() + topoffset, r, getpaddingtop() + child.getmeasuredheight() + topoffset);
   topoffset += child.getmeasuredheight();
  }
  minitscrolly = mheadview.getmeasuredheight() + getpaddingtop();
  scrollto(0, minitscrolly);

 }

 @override
 public boolean onintercepttouchevent(motionevent ev) {
  boolean intercepted = false;
  int x = (int) ev.getx();
  int y = (int) ev.gety();
  switch (ev.getaction()) {
   case motionevent.action_down:
    mlastxintercepted = x;
    mlastyintercepted = y;
    break;
   case motionevent.action_move:
    final int deltay = x - mlastyintercepted;
    if (istop() && deltay > 0 && math.abs(deltay) > mtouchslop) {
     /*下拉*/
     intercepted = true;
    }
    break;
   case motionevent.action_up:
    break;
  }
  mlastxintercepted = x;
  mlastyintercepted = y;
  return intercepted;
 }

 private void dorefresh() {
  log.i(tag, "dorefresh: ");
  if (currentstatus == status_release_to_refresh) {
   mscoller.startscroll(0, getscrolly(), 0, minitscrolly - getscrolly(), scroll_duration);
   currentstatus = status_idle;
  } else if (currentstatus == status_pull_to_refresh) {
   mscoller.startscroll(0,getscrolly(),0,0-getscrolly(),scroll_duration);
   if (null != monrefreshlistener) {
    currentstatus = status_loading;
    monrefreshlistener.refresh();
   }
  }
  invalidate();
 }

 @override
 public boolean ontouchevent(motionevent event) {
  int x = (int) event.getx();
  int y = (int) event.gety();
  switch (event.getaction()) {
   case motionevent.action_down:
    if (!mscoller.isfinished()) {
     mscoller.abortanimation();
    }
    mlastx = x;
    mlasty = y;
    break;
   case motionevent.action_move:
    if (isfisttouch) {
     isfisttouch = false;
     mlastx = x;
     mlasty = y;
    }
    final int deltay = y - mlasty;
    if (currentstatus != status_loading) {
     changescrolly(deltay);
    }
    break;
   case motionevent.action_up:
    isfisttouch = true;
    dorefresh();
    break;
  }

  mlastx = x;
  mlasty = y;
  return true;
 }

 private void changescrolly(int deltay) {
  log.i(tag, "changescrolly: ");
  int cury = getscrolly();
  if (deltay > 0) {
   /*下拉*/
   if (cury - deltay > getpaddingtop()) {
    scrollby(0, -deltay);
   }
  } else {
   /*上拉*/
   if (cury - deltay <= minitscrolly) {
    scrollby(0, -deltay);
   }
  }

  cury = getscrolly();
  int slop = minitscrolly / 2;
  if (cury > 0 && cury <=slop) {
   currentstatus = status_pull_to_refresh;
  } else if (cury > 0 && cury >= slop) {
   currentstatus = status_release_to_refresh;
  }
 }

 @override
 public void computescroll() {
  if (mscoller.computescrolloffset()) {
   scrollto(mscoller.getcurrx(), mscoller.getcurry());
   postinvalidate();
  }
 }

 /**
  * 加载完成调用这个方法
  */
 public void refreshcomplete() {
  mscoller.startscroll(0, getscrolly(), 0, minitscrolly - getscrolly(), scroll_duration);
  currentstatus = status_idle;
  invalidate();
 }

 /**
  * 显示 footer
  */
 public void showfooter() {
  if(currentstatus==status_load_more) return ;
  currentstatus = status_load_more ;
  mscoller.startscroll(0, getscrolly(), 0, mfootview.getmeasuredheight()
    , scroll_duration);
  invalidate();

 }


 /**
  * loadmore完成之后调用
  */
 public void footercomplete() {
  mscoller.startscroll(0, getscrolly(), 0, minitscrolly - getscrolly(), scroll_duration);
  invalidate();
  currentstatus = status_idle;
 }

 public interface onrefreshlistener {
  void refresh();
 }

 abstract boolean istop();

 abstract boolean isbottom();

}

它是一个抽象类，需要编写子类继承istop()和 isbottom()方法。下面给出它的一个实现类：

package com.blueberry.sample.widget.refresh;

import android.content.context;
import android.util.attributeset;
import android.widget.abslistview;
import android.widget.listview;

/**
 * created by blueberry on 2016/6/21.
 *
 * refreshlayoutbase 的一个实现类
 */
public class refreshlistview extends refreshlayoutbase<listview> {

 private static final string tag = "refreshlistview";

 private listview listview;
 private onloadlistener loadlistener;

 public refreshlistview(context context) {
  super(context);
 }

 public refreshlistview(context context, attributeset attrs) {
  super(context, attrs);
 }

 public refreshlistview(context context, attributeset attrs, int defstyleattr) {
  super(context, attrs, defstyleattr);
 }

 public listview getlistview() {
  return listview;
 }

 public void setlistview(final listview listview) {
  this.listview = listview;
  setcontentview(listview);

  this.listview.setonscrolllistener(new abslistview.onscrolllistener() {
   @override
   public void onscrollstatechanged(abslistview view, int scrollstate) {
   }

   @override
   public void onscroll(abslistview view, int firstvisibleitem, int visibleitemcount, int totalitemcount) {

    /*这里存在一个bug: 当listview滑动到底部的时候，如果下拉也会出现footer
    * 这是因为，暂时还没有想到如何判断是下拉还是上拉。
    * 如果要解决此问题，我觉得应该重写listview 的ontouchevent来判断手势方向
    * 次模块主要解决竖向滑动冲突，故现将此问题放下。
    * */
    if (currentstatus == status_idle
      && getscrolly() <= minitscrolly && isbottom()
      ) {
     showfooter();
     if (null != loadlistener) {
      loadlistener.onloadmore();
     }
    }

   }
  });
 }

 public onloadlistener getloadlistener() {
  return loadlistener;
 }

 public void setloadlistener(onloadlistener loadlistener) {
  this.loadlistener = loadlistener;
 }

 @override
 boolean istop() {
  return listview.getfirstvisibleposition() == 0
    && getscrolly() <= mheadview.getmeasuredheight();
 }

 @override
 boolean isbottom() {
  return listview.getlastvisibleposition() == listview.getadapter().getcount() - 1;
 }

 public interface onloadlistener {
  void onloadmore();
 }
}

4、内部拦截法解决同向滑动

同样是一个下拉刷新组件，因为实现原理都一样，所以这个写的比较随意些。主要还是如果解决滑动冲突。

refreshlayoutbase2.java

package com.blueberry.sample.widget.refresh;

import android.content.context;
import android.graphics.color;
import android.util.attributeset;
import android.util.log;
import android.view.motionevent;
import android.view.view;
import android.view.viewgroup;
import android.widget.arrayadapter;
import android.widget.listview;
import android.widget.scroller;

import com.blueberry.sample.r;

import java.util.arraylist;
import java.util.list;

/**
 * created by blueberry on 2016/6/22.
 * 结合内部类 listvieex
 * 内部拦截法，同向
 */
public class refreshlayoutbase2 extends viewgroup {

 private static final string tag = "refreshlayoutbase2";

 private static list<string> datas;

 static {
  datas = new arraylist<>();
  for (int i = 0; i < 40; i++) {
   datas.add("数据—" + i);
  }
 }

 private viewgroup headview;
 private listviewex lv;

 private int lasty;
 public int minitscrolly;

 private scroller mscroller;

 public refreshlayoutbase2(context context) {
  this(context, null);
 }

 public refreshlayoutbase2(context context, attributeset attrs) {
  this(context, attrs, 0);

 }

 public refreshlayoutbase2(context context, attributeset attrs, int defstyleattr) {
  super(context, attrs, defstyleattr);
  mscroller = new scroller(context);
  setupheadview(context);
  setupcontentview(context);

 }

 @override
 protected void onmeasure(int widthmeasurespec, int heightmeasurespec) {
  int widthsize = measurespec.getsize(widthmeasurespec);
  int widthmode = measurespec.getmode(widthmeasurespec);
  int height = measurespec.getsize(heightmeasurespec);
  int heightmode = measurespec.getmode(heightmeasurespec);

  int finalheight = 0;
  for (int i = 0; i < getchildcount(); i++) {
   view child = getchildat(i);
   measurechild(child, widthmeasurespec, heightmeasurespec);
   finalheight += child.getmeasuredheight();
  }

  if (widthmode == measurespec.at_most && heightmode == measurespec.at_most) {
   widthsize = getchildat(0).getmeasuredwidth();
   setmeasureddimension(widthsize, finalheight);
  } else if (widthmode == measurespec.at_most) {
   widthsize = getchildat(0).getmeasuredwidth();
   setmeasureddimension(widthsize, height);
  } else {
   setmeasureddimension(widthsize, finalheight);
  }

 }

 @override
 protected void onlayout(boolean changed, int l, int t, int r, int b) {
  int topoffset = 0;
  for (int i = 0; i < getchildcount(); i++) {
   view child = getchildat(i);
   child.layout(getpaddingleft(), getpaddingtop() + topoffset, r, getpaddingtop() + child.getmeasuredheight() + topoffset);
   topoffset += child.getmeasuredheight();
  }
  minitscrolly = headview.getmeasuredheight() + getpaddingtop();
  scrollto(0, minitscrolly);

 }

 /**
  * 不拦截down 其他一律拦截
  * @param ev
  * @return
  */
 @override
 public boolean onintercepttouchevent(motionevent ev) {
  if (ev.getaction() == motionevent.action_down) return false;
  return true;
 }

 @override
 public boolean ontouchevent(motionevent event) {
  int y = (int) event.gety();
  switch (event.getaction()) {
   case motionevent.action_down:
    break;
   case motionevent.action_move:
    final int deltay = y-lasty;
    log.i(tag, "ontouchevent: deltay: "+deltay);
    if (deltay >= 0 && lv.istop() && getscrolly() - deltay >=getpaddingtop()) {
      scrollby(0, -deltay);
    }
    break;
   case motionevent.action_up:
    this.postdelayed(new runnable() {
     @override
     public void run() {
      mscroller.startscroll(0,getscrolly(),0,minitscrolly-getscrolly());
      invalidate();
     }
    },2000);
    break;
  }

  lasty = y ;
  return true;
 }

 private void setupheadview(context context) {
  headview = (viewgroup) view.inflate(context, r.layout.fresh_head_view, null);
  headview.setbackgroundcolor(color.red);
  viewgroup.layoutparams params = new viewgroup.layoutparams(viewgroup.layoutparams.match_parent, 300);
  addview(headview, params);
 }

 public void setupcontentview(context context) {
  lv = new listviewex(context, this);
  lv.setbackgroundcolor(color.blue);
  arrayadapter<string> adapter = new arrayadapter<string>(getcontext(), android.r.layout.simple_list_item_1, datas);
  lv.setadapter(adapter);
  addview(lv, new viewgroup.layoutparams(viewgroup.layoutparams.match_parent, viewgroup.layoutparams.match_parent));
 }

 @override
 public void computescroll() {
  if(mscroller.computescrolloffset()){
   scrollto(mscroller.getcurrx(),mscroller.getcurry());
   postinvalidate();
  }
 }

 public static class listviewex extends listview {

  private refreshlayoutbase2 outter;

  public listviewex(context context, refreshlayoutbase2 outter) {
   super(context);
   this.outter = outter;
  }

  public listviewex(context context, attributeset attrs) {
   super(context, attrs);
  }

  public listviewex(context context, attributeset attrs, int defstyleattr) {
   super(context, attrs, defstyleattr);
  }

  /**
   * 使用 outter.requestdisallowintercepttouchevent();
   * 来决定父控件是否对事件进行拦截
   * @param ev
   * @return
   */
  @override
  public boolean dispatchtouchevent(motionevent ev) {
   switch (ev.getaction()) {
    case motionevent.action_down:
     outter.requestdisallowintercepttouchevent(true);
     break;
    case motionevent.action_move:

     if ( istop() && outter.getscrolly() <= outter.minitscrolly) {
      outter.requestdisallowintercepttouchevent(false);
     }
     break;

   }
   return super.dispatchtouchevent(ev);
  }

  public boolean istop() {
   return getfirstvisibleposition() ==0;
  }
 }
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。