废了好大的劲才弄好的，记下来 方便以后查看
public class MainActivity extends AppCompatActivity {
private RecyclerView mRecyclerView;
private List<String> mDatas;
private HomeAdapter mAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initData();
mRecyclerView = (RecyclerView) findViewById(R.id.id_recyclerview);
//设置布局管理器
mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
//设置adapter
mRecyclerView.setAdapter(mAdapter = new HomeAdapter());
}
protected void initData() {
mDatas = new ArrayList<String>();
for (int i = 'A'; i < 'z'; i++) {
mDatas.add("" + (char) i);
}
}
class HomeAdapter extends RecyclerView.Adapter<HomeAdapter.MyViewHolder> {
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
MyViewHolder holder = new MyViewHolder(LayoutInflater.from(
MainActivity.this).inflate(R.layout.item_home, parent,
false));
return holder;
}
@Override
public void onBindViewHolder(MyViewHolder holder, int position) {
holder.tv.setText(mDatas.get(position));
}
@Override
public int getItemCount() {
return mDatas.size();
}
class MyViewHolder extends RecyclerView.ViewHolder {
TextView tv;
public MyViewHolder(View view) {
super(view);
tv = (TextView) view.findViewById(R.id.id_num);
}
}
}
然后是最关键的NestedScrollview 是为了配合嵌套滑动的， NestedScrollview最关键有两个接口的实现 一个是 NestedScrollingChild 一个是NestedScrollingParent
先是NestedScrollingParent
public class MyNestedScrollParent extends LinearLayout implements NestedScrollingParent {
private String Tag = "MyNestedScrollParent";
private View topView ;
private View centerView;
private View contentView;
private MyNestedScrollChildL nsc ;
private NestedScrollingParentHelper mParentHelper;
private int imgHeight;
private int tvHeight;
private int mLastTouchY;
public boolean topShow;
public MyNestedScrollParent(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public MyNestedScrollParent(Context context) {
super(context);
init();
}
@Override
protected void onFinishInflate() {
super.onFinishInflate();
topView = getChildAt(0);
centerView = getChildAt(1);
contentView = getChildAt(2);
topView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
if(imgHeight<=0){
imgHeight = topView.getMeasuredHeight();
Log.i(Tag,"imgHeight:"+imgHeight+",tvHeight:"+tvHeight);
}
}
});
centerView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
if(tvHeight<=0){
tvHeight = centerView.getMeasuredHeight();
Log.i(Tag,"imgHeight:"+imgHeight+",tvHeight:"+tvHeight);
}
}
});
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
setMeasuredDimension(getMeasuredWidth(), topView.getMeasuredHeight() + centerView.getMeasuredHeight() + contentView.getMeasuredHeight());
}
public int getTopViewHeight(){
Log.i(Tag,"getTopViewHeight--"+topView.getMeasuredHeight());
return topView.getMeasuredHeight();
}
@Override
public boolean onStartNestedScroll(View child, View target, int nestedScrollAxes) {
Log.i(Tag,"onStartNestedScroll--"+"child:"+child+",target:"+target+",nestedScrollAxes:"+nestedScrollAxes);
return true;
}
private void init() {
mParentHelper = new NestedScrollingParentHelper(this);
}
@Override
public void onNestedScrollAccepted(View child, View target, int nestedScrollAxes) {
Log.i(Tag,"onNestedScrollAccepted"+"child:"+child+",target:"+target+",nestedScrollAxes:"+nestedScrollAxes);
mParentHelper.onNestedScrollAccepted(child, target, nestedScrollAxes);
}
@Override
public void onStopNestedScroll(View target) {
Log.i(Tag,"onStopNestedScroll--target:"+target);
mParentHelper.onStopNestedScroll(target);
}
@Override
public void onNestedScroll(View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed) {
Log.i(Tag,"onNestedScroll--"+"target:"+target+",dxConsumed"+dxConsumed+",dyConsumed:"+dyConsumed
+",dxUnconsumed:"+dxUnconsumed+",dyUnconsumed:"+dyUnconsumed);
}
@Override
public void onNestedPreScroll(View target, int dx, int dy, int[] consumed) {
if(showImg(dy)||hideImg(dy)){//如果父亲自己要滑动，则拦截
consumed[1]=dy;
scrollBy(0,dy);
Log.i("onNestedPreScroll","Parent滑动："+dy);
}
Log.i(Tag,"onNestedPreScroll--getScrollY():"+getScrollY()+",dx:"+dx+",dy:"+dy+",consumed:"+consumed);
}
@Override
public boolean onNestedFling(View target, float velocityX, float velocityY, boolean consumed) {
Log.i(Tag,"onNestedFling--target:"+target);
return false;
}
@Override
public boolean onNestedPreFling(View target, float velocityX, float velocityY) {
Log.i(Tag,"onNestedPreFling--target:"+target);
return false;
}
@Override
public int getNestedScrollAxes() {
Log.i(Tag,"getNestedScrollAxes");
return 0;
}
@Override
public void scrollTo(int x, int y) {
if(y<0){
y=0;
}
if(y>imgHeight){
y=imgHeight;
}
super.scrollTo(x, y);
}
/**
下拉的时候是否要向下滑动显示图片
*/
public boolean showImg(int dy){
if(dy<0){
// if(getScrollY()>0&&nsc.getScrollY()==0){//如果parent外框，还可以往上滑动
if(getScrollY()>0){
return true;
}
}
return false;
}
/**
* 上拉的时候，是否要向上滑动，隐藏图片
* @return
*/
public boolean hideImg(int dy){
if(dy>0){
if(getScrollY()<imgHeight){//如果parent外框，还可以往下滑动
return true;
}
}
return false;
}
@Override
public boolean onTouchEvent(MotionEvent event) {
if(event.getAction()==MotionEvent.ACTION_DOWN){
return true;
}
return super.onTouchEvent(event);
}
@Override
public boolean onInterceptTouchEvent(MotionEvent event) {
return super.onInterceptTouchEvent(event);
}
@Override
public boolean dispatchTouchEvent(MotionEvent event) {
Log.i("aaa","getY():getRawY:"+event.getRawY());
switch (event.getAction()){
case MotionEvent.ACTION_DOWN:
mLastTouchY = (int) (event.getRawY() + 0.5f);
break;
case MotionEvent.ACTION_MOVE:
int y = (int) (event.getRawY() + 0.5f);
int dy = mLastTouchY - y;
mLastTouchY = y;
if(showImg(dy)||hideImg(dy)){//如果父亲自己要滑动
scrollBy(0,dy);
}
break;
case MotionEvent.ACTION_UP:
break;
}
return super.dispatchTouchEvent(event);
}
}然后是NestedScrollingChild
public class MyNestedScrollChild extends ScrollView implements NestedScrollingChild {
private String Tag = "MyNestedScrollChild";
private NestedScrollingChildHelper mScrollingChildHelper;
public MyNestedScrollChild(Context context) {
super(context);
init(context);
}
public MyNestedScrollChild(Context context, AttributeSet attrs) {
super(context, attrs);
init(context);
}
public MyNestedScrollChild(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(context);
}
public void init(Context context) {
final ViewConfiguration configuration = ViewConfiguration.get(context);
}
@Override
public void setNestedScrollingEnabled(boolean enabled) {
Log.i(Tag, "setNestedScrollingEnabled:" + enabled);
getScrollingChildHelper().setNestedScrollingEnabled(enabled);
}
@Override
public boolean isNestedScrollingEnabled() {
Log.i(Tag, "isNestedScrollingEnabled");
return getScrollingChildHelper().isNestedScrollingEnabled();
}
@Override
public boolean startNestedScroll(int axes) {
boolean bl = getScrollingChildHelper().startNestedScroll(axes);
Log.i(Tag, "startNestedScroll:axes=" + axes + ",bl:" + bl);
Log.i(Tag, "hasNestedScrollingParent=" + getScrollingChildHelper().hasNestedScrollingParent());
return bl;
}
@Override
public void stopNestedScroll() {
Log.i(Tag, "stopNestedScroll");
getScrollingChildHelper().stopNestedScroll();
}
@Override
public boolean hasNestedScrollingParent() {
Log.i(Tag, "hasNestedScrollingParent");
return getScrollingChildHelper().hasNestedScrollingParent();
}
@Override
public boolean dispatchNestedScroll(int dxConsumed, int dyConsumed, int dxUnconsumed,
int dyUnconsumed, int[] offsetInWindow) {
Log.i(Tag, "dispatchNestedScroll:dxConsumed:" + dxConsumed + "," +
"dyConsumed:" + dyConsumed + ",dxUnconsumed:" + dxUnconsumed + ",dyUnconsumed:" +
dyUnconsumed + ",offsetInWindow:" + offsetInWindow);
return getScrollingChildHelper().dispatchNestedScroll(dxConsumed, dyConsumed,
dxUnconsumed, dyUnconsumed, offsetInWindow);
}
@Override
public boolean dispatchNestedPreScroll(int dx, int dy, int[] consumed, int[] offsetInWindow) {
Log.i(Tag, "dispatchNestedPreScroll:dx" + dx + ",dy:" + dy + ",consumed:" + consumed + ",offsetInWindow:" + offsetInWindow);
return getScrollingChildHelper().dispatchNestedPreScroll(dx, dy, consumed, offsetInWindow);
}
@Override
public boolean dispatchNestedFling(float velocityX, float velocityY, boolean consumed) {
Log.i(Tag, "dispatchNestedFling:velocityX:" + velocityX + ",velocityY:" + velocityY + ",consumed:" + consumed);
return getScrollingChildHelper().dispatchNestedFling(velocityX, velocityY, consumed);
}
@Override
public boolean dispatchNestedPreFling(float velocityX, float velocityY) {
Log.i(Tag, "dispatchNestedPreFling:velocityX:" + velocityX + ",velocityY:" + velocityY);
return getScrollingChildHelper().dispatchNestedPreFling(velocityX, velocityY);
}
private NestedScrollingChildHelper getScrollingChildHelper() {
if (mScrollingChildHelper == null) {
mScrollingChildHelper = new NestedScrollingChildHelper(this);
mScrollingChildHelper.setNestedScrollingEnabled(true);
}
return mScrollingChildHelper;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
setMeasuredDimension(getMeasuredWidth(),getMeasuredHeight()+((MyNestedScrollParent)getParent()).getTopViewHeight());
}
}布局文件
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.lmj.com.mynestscroll.MainActivity"> <com.lmj.com.mynestscroll.view.MyNestedScrollParent
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#0f0"
android:clickable="true"
android:orientation="vertical"> <LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
> <TextView
android:id="@+id/tv_search"
android:layout_width="match_parent"
android:layout_height="100dp"
android:gravity="center"
android:padding="20dp"
android:text="搜索" /> <LinearLayout
android:id="@+id/ll_other"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginLeft="20dp"
android:layout_marginRight="20dp"
android:orientation="vertical"> <TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#30ffffff"
android:drawablePadding="10dp"
android:gravity="center_vertical"
android:padding="10dp"
android:text="任何地方"
android:textColor="#fff" /> <TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:background="#30ffffff"
android:drawablePadding="10dp"
android:padding="10dp"
android:text="任何时间"
android:textColor="#fff" /> <TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:background="#30ffffff"
android:drawablePadding="10dp"
android:padding="10dp"
android:text="房客"
android:textColor="#fff" /> </LinearLayout>
</LinearLayout> <TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#f0f"
android:text="@string/topStr" /> <com.lmj.com.mynestscroll.view.MyNestedScrollChild
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="1231231231312"
/> </com.lmj.com.mynestscroll.view.MyNestedScrollChild> <!--<com.lmj.com.mynestscroll.MyRecycleView-->
<!--android:id="@+id/id_recyclerview"-->
<!--android:layout_width="match_parent"-->
<!--android:layout_height="match_parent">--> <!--</com.lmj.com.mynestscroll.MyRecycleView>--> </com.lmj.com.mynestscroll.view.MyNestedScrollParent> </RelativeLayout>
NestedScrollingChild和NestedScrollingParent之间的部分，在滑动时会悬浮在顶部 而RecycleView 本身已经实现了NestedScrollingChild 我们在使用RecycleView的时候 需要重写onMeasure方法
public class MyRecycleView extends RecyclerView {
public MyRecycleView(Context context) {
super(context);
}
public MyRecycleView(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
}
public MyRecycleView(Context context, @Nullable AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
@Override
protected void onMeasure(int widthSpec, int heightSpec) {
super.onMeasure(widthSpec, heightSpec);
setMeasuredDimension(getMeasuredWidth(),getMeasuredHeight()+((MyNestedScrollParent)getParent()).getTopViewHeight());
}
}重新设定RecycleView的高度