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。
人之所以能，是相信能。
