在上一节，我们讲了view滑动冲突的解决方案，在这一节中，我们将要对此进行实践。我们来实现类似于在viewpage中嵌套listview的滑动效果，为了展示冲突效果我们写一个类似于viewpage的空间HorizontalScrollerViewEX，为了实现viewpage的效果，我们自定义一个类似于横向linnerlayout的控件，我们在他的内部添加很多个listview，这样它既可以横向滑动，又可以竖直滑动，我们来解决冲突问题。
下面是自定义view：
package com.example.animotiontest.view;
import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.Scroller;
public class HorizontalScrollerViewEX extends LinearLayout {
private static final String TAG = "HorizontalScrollerViewEX";
private int mChildrenSize;
private int mChildWith;
private int mChildIndex;
// 分别记录上次滑动的坐标
private int mLastX = 0;
private int mLastY = 0;
// 分别记录上次滑动的坐标（onInterceptTouchEvent）
private int mLastXIntercept = 0;
private int mLastYIntercept = 0;
private Scroller mScroller;
private VelocityTracker mVelocityTracker;
private Context context;
public HorizontalScrollerViewEX(Context context) {
this(context, null);
this.context = context;
}
public HorizontalScrollerViewEX(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public HorizontalScrollerViewEX(Context context, AttributeSet attrs,
int defStyle) {
super(context, attrs, defStyle);
init();
}
private void init() {
mScroller = new Scroller(context);
mVelocityTracker = VelocityTracker.obtain();
}
@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:
intercepted = false;
if (!mScroller.isFinished()) {
mScroller.abortAnimation();
intercepted = true;
}
break;
case MotionEvent.ACTION_MOVE:
int deltaX = x - mLastXIntercept;
int deltaY = y - mLastYIntercept;
// 取滑动距离的绝对值
if (Math.abs(deltaX) > Math.abs(deltaY)) {
intercepted = true;
} else {
intercepted = false;
}
break;
case MotionEvent.ACTION_UP:
intercepted = false;
default:
break;
}
Log.d(TAG, "intercepted=" + intercepted);
mLastX = x;
mLastY = y;
mLastXIntercept = x;
mLastYIntercept = y;
return intercepted;
}
@Override
public boolean onTouchEvent(MotionEvent event) {
int x = (int) event.getX();
int y = (int) event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
if (!mScroller.isFinished()) {
mScroller.abortAnimation();
}
break;
case MotionEvent.ACTION_MOVE:
int deltax = x - mLastX;
int deltay = y - mLastY;
scrollBy(-deltax, 0);
break;
case MotionEvent.ACTION_UP:
int scrollX = getScrollX();
int scrollToChildIndex = scrollX / mChildWith;
mVelocityTracker.computeCurrentVelocity(1000);
float xVelocity = mVelocityTracker.getXVelocity();
if (Math.abs(xVelocity) >= 50) {
mChildIndex = xVelocity > 0 ? mChildIndex - 1 : mChildIndex + 1;
} else {
mChildIndex = (scrollX + mChildWith / 2) / mChildWith;
}
mChildIndex = Math.max(0, Math.min(mChildIndex, mChildrenSize - 1));
int dx = mChildIndex * mChildWith - scrollX;
smoothScrollTo(dx, 0);
mVelocityTracker.clear();
default:
break;
}
mLastX = x;
mLastY = y;
return true;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
int measuredWidth = 0;
int measuredHeight = 0;
final int childCount = getChildCount();
measureChildren(widthMeasureSpec, heightMeasureSpec);
int widthSpaceSize = MeasureSpec.getSize(widthMeasureSpec);
int widthSpecMode = MeasureSpec.getMode(widthMeasureSpec);
int heightSpaceSize = MeasureSpec.getSize(heightMeasureSpec);
int heightSpaceMode = MeasureSpec.getMode(heightMeasureSpec);
if (childCount == 0) {
setMeasuredDimension(0, 0);
} else if (heightSpaceMode == MeasureSpec.AT_MOST) {
final View childView = getChildAt(0);
measuredHeight = childView.getMeasuredWidth();
setMeasuredDimension(widthMeasureSpec,
childView.getMeasuredHeight());
} else if (widthSpecMode == MeasureSpec.AT_MOST) {
final View childView = getChildAt(0);
measuredWidth = childView.getMeasuredWidth() * childCount;
setMeasuredDimension(measuredWidth, heightSpaceSize);
} else {
final View childView = getChildAt(0);
measuredWidth = childView.getMeasuredWidth() * childCount;
measuredHeight = childView.getMeasuredHeight();
setMeasuredDimension(measuredWidth, measuredHeight);
}
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
int childLeft = 0;
final int childCount = getChildCount();
mChildrenSize = childCount;
for (int i = 0; i < childCount; i++) {
final View childView = getChildAt(i);
if (childView.getVisibility() != View.GONE) {
final int childWidth = childView.getMeasuredWidth();
mChildWith = childWidth;
childView.layout(childLeft, 0, childLeft,
childView.getMeasuredHeight());
childLeft += childWidth;
}
}
}
/**
* 缓慢滑动到指定位置
*
* @param destX
* @param destY
*/
private void smoothScrollTo(int destX, int destY) {
mScroller.startScroll(getScrollX(), 0, destX, 500);
invalidate();
}
@Override
public void computeScroll() {
if (mScroller.computeScrollOffset()) {
scrollTo(mScroller.getCurrX(), mScroller.getCurrY());
postInvalidate();
}
// TODO Auto-generated method stub
super.computeScroll();
}
@Override
protected void onDetachedFromWindow() {
mVelocityTracker.recycle();
super.onDetachedFromWindow();
}
}从上面的代码来看，我们是使用外部拦截法实现了冲突事件的解决，在滑动过程中，当水平距离大时，就判断为水平滑动，为了能够水平滑动，所以让父容器拦截事件，而竖直距离大时父容器就不拦截事件，于是事件就传递给了listview，如此listview也实现了上下滑动，所以就解决了滑动冲突问题。
我们继续来看看activity中代码的实现
package com.example.animotiontest.activity;
import java.util.ArrayList;
import com.example.animotiontest.R;
import com.example.animotiontest.uitls.MyUtils;
import com.example.animotiontest.view.HorizontalScrollerViewEX;
import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
public class DemoActivity1 extends Activity {
private static final String TAG = "DemoActivity1";
private HorizontalScrollerViewEX mListContainer;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_demo1);
Log.d(TAG, "oncreate");
initView();
}
private void initView() {
LayoutInflater inflater = getLayoutInflater();
mListContainer = (HorizontalScrollerViewEX) findViewById(R.id.container);
final int screenWith = MyUtils.getScreenMetrics(this).widthPixels;
final int screenheight = MyUtils.getScreenMetrics(this).heightPixels;
for (int i = 0; i < 3; i++) {
ViewGroup layout = (ViewGroup) inflater.inflate(
R.layout.content_layout, mListContainer, false);
layout.getLayoutParams().width = screenWith;
TextView textView = (TextView) layout.findViewById(R.id.title);
textView.setText("page" + (i + 1));
layout.setBackgroundColor(Color
.rgb(255 / (i + 1), 255 / (i + 1), 0));
createList(layout);
mListContainer.addView(layout);
}
}
private void createList(ViewGroup layout) {
ListView listView = (ListView) layout.findViewById(R.id.list);
ArrayList<String> datas = new ArrayList<String>();
for (int i = 0; i < 50; i++) {
datas.add("name" + i);
}
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
R.layout.content_list_item, R.id.name, datas);
listView.setAdapter(adapter);
listView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// TODO Auto-generated method stub
Toast.makeText(DemoActivity1.this, "click item",
Toast.LENGTH_SHORT).show();
}
});
}
}
上面的代码很简单，就是把三个listview添加到我们自定义的HorizontalScrollerViewEX布局里边，在这里HorizontalScrollerViewEX是父容器，而listview是子view；我们上边采用的室外不拦截法实现的滑动区分；
下面来看看获取屏幕高和宽的工具类
public static DisplayMetrics getScreenMetrics(Context context) {
WindowManager wm = (WindowManager) context
.getSystemService(Context.WINDOW_SERVICE);
DisplayMetrics dm = new DisplayMetrics();
wm.getDefaultDisplay().getMetrics(dm);
return dm;
}
package com.example.animotiontest.view;
import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.widget.ListView;
public class ListViewEx extends ListView {
private static final String TAG = "ListViewEx";
private HorizontalScrollerViewEX2 mHorizontalScrollViewEx2;
// 分别记录上次滑动的坐标
private int mLastX = 0;
private int mLastY = 0;
public ListViewEx(Context context) {
super(context);
}
public ListViewEx(Context context, AttributeSet attrs) {
super(context, attrs);
}
public ListViewEx(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
public void setHorizontalScrollViewEx2(
HorizontalScrollerViewEX2 horizontalScrollViewEx2) {
mHorizontalScrollViewEx2 = horizontalScrollViewEx2;
}
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
int x = (int) ev.getX();
int y = (int) ev.getY();
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
mHorizontalScrollViewEx2.requestDisallowInterceptTouchEvent(true);
break;
case MotionEvent.ACTION_MOVE:
int deltaX = x - mLastX;
int deltaY = y - mLastY;
if (Math.abs(deltaX) > Math.abs(deltaY)) {
mHorizontalScrollViewEx2
.requestDisallowInterceptTouchEvent(false);
}
break;
case MotionEvent.ACTION_UP:
break;
default:
break;
}
mLastX = x;
mLastY = y;
return super.dispatchTouchEvent(ev);
}
}
HorizontalScrollerViewEX2 为
package com.example.animotiontest.view;
import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import android.view.View;
import android.view.ViewGroup;
import android.view.View.MeasureSpec;
import android.widget.Scroller;
public class HorizontalScrollerViewEX2 extends ViewGroup {
private static final String TAG = "HorizontalScrollViewEx2";
private int mChildrenSize;
private int mChildWidth;
private int mChildIndex;
// 分别记录上次华东的坐标
private int mLastX = 0;
private int mLastY = 0;
// 分别记录上次滑动的坐标（onInterceptTouchEvent）
private int mLastXIntercept = 0;
private int mLastYIntercept = 0;
private Scroller mScroller;
private VelocityTracker mVelocityTracker;
private Context context;
public HorizontalScrollerViewEX2(Context context) {
this(context, null);
}
public HorizontalScrollerViewEX2(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public HorizontalScrollerViewEX2(Context context, AttributeSet attrs,
int defStyle) {
super(context, attrs, defStyle);
this.context = context;
init();
}
private void init() {
mScroller = new Scroller(context);
mVelocityTracker = VelocityTracker.obtain();
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
int x = (int) ev.getX();
int y = (int) ev.getY();
int action = ev.getAction();
if (action == MotionEvent.ACTION_DOWN) {
mLastX = x;
mLastY = y;
if (!mScroller.isFinished()) {
mScroller.abortAnimation();
return true;
}
return false;
} else {
return true;
}
}
@Override
public boolean onTouchEvent(MotionEvent event) {
Log.d(TAG, "onTouchEvent action:" + event.getAction());
mVelocityTracker.addMovement(event);
int x = (int) event.getX();
int y = (int) event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
if (!mScroller.isFinished()) {
mScroller.abortAnimation();
}
break;
case MotionEvent.ACTION_MOVE:
int deltaX = x - mLastX;
int deltaY = y - mLastY;
scrollBy(-deltaX, 0);
break;
case MotionEvent.ACTION_UP:
int scrollX = getScrollX();
int scrollToChildIndex = scrollX / mChildWidth;
Log.d(TAG, "current index:" + scrollToChildIndex);
mVelocityTracker.computeCurrentVelocity(1000);
float xVelocity = mVelocityTracker.getXVelocity();
if (Math.abs(xVelocity) >= 50) {
mChildIndex = xVelocity > 0 ? mChildIndex - 1 : mChildIndex + 1;
} else {
mChildIndex = (scrollX + mChildWidth / 2) / mChildWidth;
}
mChildIndex = Math.max(0, Math.min(mChildIndex, mChildrenSize - 1));
int dx = mChildIndex * mChildWidth - scrollX;
smoothScrollBy(dx, 0);
mVelocityTracker.clear();
Log.d(TAG, "index:" + scrollToChildIndex + " dx:" + dx);
break;
default:
break;
}
mLastX = x;
mLastY = y;
return true;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
int measuredWidth = 0;
int measuredHeight = 0;
final int childCount = getChildCount();
measureChildren(widthMeasureSpec, heightMeasureSpec);
int widthSpaceSize = MeasureSpec.getSize(widthMeasureSpec);
int widthSpecMode = MeasureSpec.getMode(widthMeasureSpec);
int heightSpaceSize = MeasureSpec.getSize(heightMeasureSpec);
int heightSpecMode = MeasureSpec.getMode(heightMeasureSpec);
if (childCount == 0) {
setMeasuredDimension(0, 0);
} else if (heightSpecMode == MeasureSpec.AT_MOST) {
final View childView = getChildAt(0);
measuredHeight = childView.getMeasuredHeight();
setMeasuredDimension(widthSpaceSize, childView.getMeasuredHeight());
} else if (widthSpecMode == MeasureSpec.AT_MOST) {
final View childView = getChildAt(0);
measuredWidth = childView.getMeasuredWidth() * childCount;
setMeasuredDimension(measuredWidth, heightSpaceSize);
} else {
final View childView = getChildAt(0);
measuredWidth = childView.getMeasuredWidth() * childCount;
measuredHeight = childView.getMeasuredHeight();
setMeasuredDimension(measuredWidth, measuredHeight);
}
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
Log.d(TAG, "width:" + getWidth());
int childLeft = 0;
final int childCount = getChildCount();
mChildrenSize = childCount;
for (int i = 0; i < childCount; i++) {
final View childView = getChildAt(i);
if (childView.getVisibility() != View.GONE) {
final int childWidth = childView.getMeasuredWidth();
mChildWidth = childWidth;
childView.layout(childLeft, 0, childLeft + childWidth,
childView.getMeasuredHeight());
childLeft += childWidth;
}
}
}
private void smoothScrollBy(int dx, int dy) {
mScroller.startScroll(getScrollX(), 0, dx, 0, 500);
invalidate();
}
@Override
public void computeScroll() {
if (mScroller.computeScrollOffset()) {
scrollTo(mScroller.getCurrX(), mScroller.getCurrY());
postInvalidate();
}
}
@Override
protected void onDetachedFromWindow() {
mVelocityTracker.recycle();
super.onDetachedFromWindow();
}
}
以上就是内部拦截的实现 其中 mScroller.abortAnimation();不是必须的，这里是为了优化滑动体验问题。从上可以看出来内部拦截发烧为复杂一些，推荐使用外部拦截法。本文章为转载内容，我们尊重原作者对文章享有的著作权。如有内容错误或侵权问题，欢迎原作者联系我们进行内容更正或删除文章。
