在之前的项目中，因为首页使用了CoordinatorLayout+AppBarLayout+ViewPager+recycview的架构，在华为手机上出现了滑动抖动的情况，因为在开发的过程中没有发现这个问题（最后是在老板的手机上出现的，揪心），最后反馈到部门来，所以当时就紧急排查原因并很快解决，今天就记录下当时排查的过程
首先我们制定View的滑动有两种scoll和fling,这个问题就出在这个fling上，当AppBarLayout还在向下滑动fling时，这个时候再去触发Recycview的向上滑动就会导致抖动。
知道原因我们怎么去解决了呢？
通过自定义Behavior处理滑动
public class FlingBehavior extends AppBarLayout.Behavior {
private static final int TOP_CHILD_FLING_THRESHOLD = 3;
private boolean isPositive;
private static final String TAG = "AppbarLayoutBehavior";
private static final int TYPE_FLING = 1;
private boolean isFlinging;
private boolean shouldBlockNestedScroll;
public FlingBehavior() {
super();
}
public FlingBehavior(Context context, AttributeSet attrs) {
super(context, attrs);
}
@Override
public boolean onInterceptTouchEvent(CoordinatorLayout parent, AppBarLayout child, MotionEvent ev) {
LogUtil.d(TAG, "onInterceptTouchEvent:" + child.getTotalScrollRange());
shouldBlockNestedScroll = isFlinging;
switch (ev.getActionMasked()) {
case MotionEvent.ACTION_DOWN:
//手指触摸屏幕的时候停止fling事件
stopAppbarLayoutFling(child);
break;
default:
break;
}
return super.onInterceptTouchEvent(parent, child, ev);
}
/**
* 反射获取私有的flingRunnable 属性，考虑support 28以后变量名修改的问题
* @return Field
* @throws NoSuchFieldException
*/
private Field getFlingRunnableField() throws NoSuchFieldException {
Class<?> superclass = this.getClass().getSuperclass();
try {
// support design 27及一下版本
Class<?> headerBehaviorType = null;
if (superclass != null) {
headerBehaviorType = superclass.getSuperclass();
}
if (headerBehaviorType != null) {
return headerBehaviorType.getDeclaredField("mFlingRunnable");
}else {
return null;
}
} catch (NoSuchFieldException e) {
e.printStackTrace();
// 可能是28及以上版本
Class<?> headerBehaviorType = superclass.getSuperclass().getSuperclass();
if (headerBehaviorType != null) {
return headerBehaviorType.getDeclaredField("flingRunnable");
} else {
return null;
}
}
}
/**
* 反射获取私有的scroller 属性，考虑support 28以后变量名修改的问题
* @return Field
* @throws NoSuchFieldException
*/
private Field getScrollerField() throws NoSuchFieldException {
Class<?> superclass = this.getClass().getSuperclass();
try {
// support design 27及一下版本
Class<?> headerBehaviorType = null;
if (superclass != null) {
headerBehaviorType = superclass.getSuperclass();
}
if (headerBehaviorType != null) {
return headerBehaviorType.getDeclaredField("mScroller");
}else {
return null;
}
} catch (NoSuchFieldException e) {
e.printStackTrace();
// 可能是28及以上版本
Class<?> headerBehaviorType = superclass.getSuperclass().getSuperclass();
if (headerBehaviorType != null) {
return headerBehaviorType.getDeclaredField("scroller");
}else {
return null;
}
}
}
/**
* 停止appbarLayout的fling事件
* @param appBarLayout
*/
private void stopAppbarLayoutFling(AppBarLayout appBarLayout) {
//通过反射拿到HeaderBehavior中的flingRunnable变量
try {
Field flingRunnableField = getFlingRunnableField();
Field scrollerField = getScrollerField();
if (flingRunnableField != null) {
flingRunnableField.setAccessible(true);
}
if (scrollerField != null) {
scrollerField.setAccessible(true);
}
Runnable flingRunnable = null;
if (flingRunnableField != null) {
flingRunnable = (Runnable) flingRunnableField.get(this);
}
OverScroller overScroller = (OverScroller) scrollerField.get(this);
if (flingRunnable != null) {
LogUtil.d(TAG, "存在flingRunnable");
appBarLayout.removeCallbacks(flingRunnable);
flingRunnableField.set(this, null);
}
if (overScroller != null && !overScroller.isFinished()) {
overScroller.abortAnimation();
}
} catch (NoSuchFieldException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
}
@Override
public boolean onStartNestedScroll(CoordinatorLayout parent, AppBarLayout child,
View directTargetChild, View target,
int nestedScrollAxes, int type) {
LogUtil.d(TAG, "onStartNestedScroll");
stopAppbarLayoutFling(child);
return super.onStartNestedScroll(parent, child, directTargetChild, target,
nestedScrollAxes, type);
}
@Override
public void onNestedPreScroll(CoordinatorLayout coordinatorLayout,
AppBarLayout child, View target,
int dx, int dy, int[] consumed, int type) {
LogUtil.d(TAG, "onNestedPreScroll:" + child.getTotalScrollRange()
+ " ,dx:" + dx + " ,dy:" + dy + " ,type:" + type);
//type返回1时，表示当前target处于非touch的滑动，
//该bug的引起是因为appbar在滑动时，CoordinatorLayout内的实现NestedScrollingChild2接口的滑动
//子类还未结束其自身的fling
//所以这里监听子类的非touch时的滑动，然后block掉滑动事件传递给AppBarLayout
if (type == TYPE_FLING) {
isFlinging = true;
}
if (!shouldBlockNestedScroll) {
super.onNestedPreScroll(coordinatorLayout, child, target, dx, dy, consumed, type);
}
}
@Override
public void onNestedScroll(CoordinatorLayout coordinatorLayout, AppBarLayout child,
View target, int dxConsumed, int dyConsumed, int
dxUnconsumed, int dyUnconsumed, int type) {
LogUtil.d(TAG, "onNestedScroll: target:" + target.getClass() + " ,"
+ child.getTotalScrollRange() + " ,dxConsumed:"
+ dxConsumed + " ,dyConsumed:" + dyConsumed + " " + ",type:" + type);
if (!shouldBlockNestedScroll) {
super.onNestedScroll(coordinatorLayout, child, target, dxConsumed,
dyConsumed, dxUnconsumed, dyUnconsumed, type);
}
}
@Override
public void onStopNestedScroll(CoordinatorLayout coordinatorLayout, AppBarLayout abl,
View target, int type) {
LogUtil.d(TAG, "onStopNestedScroll");
super.onStopNestedScroll(coordinatorLayout, abl, target, type);
isFlinging = false;
shouldBlockNestedScroll = false;
}
private static class LogUtil{
static void d(String tag, String string){
Log.d(tag,string);
}
}
}
<com.google.android.material.appbar.AppBarLayout
android:id="@+id/appbar_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@color/transparent"
app:layout_behavior="com.betawm.baw.widget.FlingBehavior">
在xml布局里使用
