android多種滑動沖突的解決方案

一、前言

Android 中解決滑動的方案有2種：外部攔截法 和內部攔截法。

滑動沖突也存在2種場景: 橫豎滑動沖突、同向滑動沖突。

所以我就寫了4個例子來學習如何解決滑動沖突的，這四個例子分別為: 外部攔截法解決橫豎沖突、外部攔截法解決同向沖突、內部攔截法解決橫豎沖突、內部攔截法解決同向沖突。

先上效果圖：

二、實戰

1、外部攔截法，解決橫豎沖突

思路是，重寫父控件的onInterceptTouchEvent方法，然後根據具體的需求，來決定父控件是否攔截事件。如果攔截返回返回true，不攔截返回false。如果父控件攔截了事件，則在父控件的onTouchEvent進行相應的事件處理。

我的這個例子，是一個橫向滑動的ViewGroup裡面包含了3個豎向滑動的ListView。下面我附上代碼，HorizontalEx.Java：

/**
 * Created by blueberry on 2016/6/20.
 *
 * 解決交錯的滑動沖突
 *
 * 外部攔截法
 */
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();
  }
 }

 /**
  * 攔截事件
  * @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()) {
   /*如果攔截了Down事件,則子類不會拿到這個事件序列*/
   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;
    /*根據條件判斷是否攔截該事件*/
    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:
    /*因為這裡父控件拿不到Down事件，所以使用一個布爾值，
     當事件第一次來到父控件時，對lastX,lastY賦值*/
    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();
 }
}

調用代碼：

@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);
 }

其實外部攔截的主要思想都在於對onInterceptTouchEvent的重寫。

@Override
 public boolean onInterceptTouchEvent(MotionEvent ev) {
  boolean intercepted = false;
  int x = (int) ev.getX();
  int y = (int) ev.getY();

  switch (ev.getAction()) {
   /*如果攔截了Down事件,則子類不會拿到這個事件序列*/
   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;
    /*根據條件判斷是否攔截該事件*/
    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;
 }

這幾乎是一個實現外部攔截事件的模板，這裡一定不要在ACTION_DOWN 中返回 true,否則會讓子VIew沒有機會得到事件，因為如果在ACTION_DOWN的時候返回了 true,同一個事件序列ViewGroup的disPatchTouchEvent就不會在調用onInterceptTouchEvent方法了。

還有就是 在ACTION_UP中返回false，因為如果父控件攔截了ACTION_UP，那麼子View將得不到UP事件，那麼將會影響子View的 Onclick方法等。但這對父控件是沒有影響的，因為如果是父控件子ACITON_MOVE中 就攔截了事件，他們UP事件必定也會交給它處理，因為有那麼一條定律叫做：父控件一但攔截了事件，那麼同一個事件序列的所有事件都將交給他處理。這條結論在我的上一篇文章中已經分析過。

最後就是在 ACTION_MOVE中根據需求決定是否攔截。

2、內部攔截法，解決橫豎沖突

內部攔截主要依賴於父控件的 requestDisallowInterceptTouchEvent方法，關於這個方法我的上篇文章其實已經分析過。他設置父控件的一個標志（FLAG_DISALLOW_INTERCEPT）

這個標志可以決定父控件是否攔截事件，如果設置了這個標志則不攔截，如果沒設這個標志，它就會調用父控件的onInterceptTouchEvent（）來詢問父控件是否攔截。但這個標志對Down事件無效。

可以參考一下源碼：   

 // 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);
    //清楚標志
    resetTouchState();
   }

   // Check for interception.
   final boolean intercepted;
   if (actionMasked == MotionEvent.ACTION_DOWN
     || mFirstTouchTarget != null) {
     //標志
    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;
   }

那麼我們如果想使用 內部攔截法攔截事件。

第一步：

a、我們要重寫父控件的onInterceptTouchEvent，在ACTION_DOWN的時候返回false,負責的話子View調用requestDisallowInterceptTouchEvent也將無能為力。

b、還有就是其他事件的話都返回true,這樣就把能否攔截事件的權利交給了子View。

第二步:

在子View的dispatchTouchEvent中 來決定是否讓父控件攔截事件。

a. 先要在MotionEvent.ACTION_DOWN:的時候使用mHorizontalEx2.requestDisallowInterceptTouchEvent(true);，負責的話，下一個事件到來時，就交給父控件了。

b. 然後在MotionEvent.ACTION_MOVE: 根據業務邏輯決定是否調用mHorizontalEx2.requestDisallowInterceptTouchEvent(false);來決定父控件是否攔截事件。

上代碼HorizontalEx2.java:

/**
 * Created by blueberry on 2016/6/20.
 * 內部攔截
 * 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();
  }
 }

 /**
  * 不攔截Down事件，其他一律攔截
  * @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

/**
 * 內部攔截事件
 */
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();
  * 來決定父控件是否對事件進行攔截
  * @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);
 }
}

調用代碼：

 @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種攔截方法已經學習完畢，下面我們來學習如何解決同向滑動沖突。

其實和上面的2個例子思路是一樣的，只是用來判斷是否攔截的那塊邏輯不同而已。

下面的例子，是一個下拉刷新的一個控件。

3、外部攔截 解決同向滑動沖突

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;

/**

 *外部攔截(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);
 }

 /**
  * 設置頭布局
  */
 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);
  /*設置 實際高度為 1/4 ，但內容區域只有 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);
 }

 /**
  * 設置尾布局
  */
 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();
  }
 }

 /**
  * 加載完成調用這個方法
  */
 public void refreshComplete() {
  mScoller.startScroll(0, getScrollY(), 0, mInitScrollY - getScrollY(), SCROLL_DURATION);
  currentStatus = STATUS_IDLE;
  invalidate();
 }

 /**
  * 顯示 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完成之後調用
  */
 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();

}

它是一個抽象類，需要編寫子類繼承isTop()和 isBottom()方法。下面給出它的一個實現類：

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 的一個實現類
 */
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) {

    /*這裡存在一個bug: 當listView滑動到底部的時候，如果下拉也會出現footer
    * 這是因為，暫時還沒有想到如何判斷是下拉還是上拉。
    * 如果要解決此問題，我覺得應該重寫listView 的onTouchEvent來判斷手勢方向
    * 次模塊主要解決豎向滑動沖突，故現將此問題放下。
    * */
    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、內部攔截法解決同向滑動

同樣是一個下拉刷新組件，因為實現原理都一樣，所以這個寫的比較隨意些。主要還是如果解決滑動沖突。

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.
 * 結合內部類 ListVieEx
 * 內部攔截法，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("數據—" + 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);

 }

 /**
  * 不攔截Down 其他一律攔截
  * @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();
   * 來決定父控件是否對事件進行攔截
   * @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;
  }
 }
}

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