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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，然后根據具體的需求，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里面包含了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:
/*因為這里父控件拿不到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于對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，這里一定不要在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，那么子View將得不到UP事件，那么將會影響子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，因為有那么一條定律叫做：父控件一但攔截了事件，那么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。
最后就是在 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
內部攔截主要依賴于父控件的 requestDisallowInterceptTouchEvent方法，關于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;
}
那么我們如果想使用 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. 然后在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完成之后調用
*/
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) {
/*這里存在一個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;
}
}
}
以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持億速云。
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