Android 获取Infinite RecyclerView的中心可见项值
我已经创建了一个循环回收视图，通过将适配器计数为Integer.MAX。现在，我需要突出显示图像中的中心回收器项目。请帮助我 在BindView中，您可以检查适配器的中间位置，并为特定支架的图像应用逻辑Android 获取Infinite RecyclerView的中心可见项值,android,Android,我已经创建了一个循环回收视图，通过将适配器计数为Integer.MAX。现在，我需要突出显示图像中的中心回收器项目。请帮助我 在BindView中，您可以检查适配器的中间位置，并为特定支架的图像应用逻辑 onBindViewHolder(View holder, int postion){ if(position == getItemCount() / 2) { //Write image logic for holder }} 如果要使用horizontalscrollview（动态创建
onBindViewHolder(View holder, int postion){
if(position == getItemCount() / 2)
{ //Write image logic for holder
}}
如果要使用horizontalscrollview（动态创建项）而不是recyclerview 创建父布局
<HorizontalScrollView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true">
<LinearLayout
android:layout_alignParentBottom="true"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"/>
</HorizontalScrollView>
<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"
>
<TextView
android:layout_width="wrap_content"
android:text="↓"
android:id="@+id/centerIndicator"
android:textSize="24sp"
android:textStyle="bold"
android:visibility="visible"
android:textColor="@color/theme_yellow"
android:layout_centerHorizontal="true"
android:layout_height="wrap_content"
android:layout_marginTop="27dp"
android:background="@android:color/transparent"
/>
<android.support.v7.widget.RecyclerView
android:layout_width="match_parent"
android:id="@+id/list"
android:clipToPadding="false"
android:divider="@android:color/transparent"
android:layout_height="wrap_content"/>
</RelativeLayout>
public class Sample extends Fragment {
RecyclerView listView;
ArrayList<String>mWeekDaysList=new ArrayList<>();
LinearLayoutManager mlinearLayoutManagerForDateList;
DateAdapter mDateAdapter;
TimeListAdapter mtimeAdapter;
private int mCenterPivot;
private boolean mAutoSet = true;
Activity mactivity;
public NigaichiNiralFrag() {
// Required empty public constructor
}
@Override
public View onCreateView(final LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view= inflater.inflate(R.layout.fragment_nigaichi_niral, container, false);
mactivity=getActivity();
mWeekDaysList.add("Sunday");
mWeekDaysList.add("Monday");
mWeekDaysList.add("Tuesday");
mWeekDaysList.add("Wednesday");
mWeekDaysList.add("Thursday");
mWeekDaysList.add("Friday");
mWeekDaysList.add("Saturday");
listView = (RecyclerView) view.findViewById(R.id.list);
mlinearLayoutManagerForDateList = new LinearLayoutManager(mactivity);
mlinearLayoutManagerForDateList.setOrientation(LinearLayoutManager.HORIZONTAL);
listView.setLayoutManager(mlinearLayoutManagerForDateList);
final TextView mCenterIndicator = (TextView) view.findViewById(R.id.centerIndicator);
final int itemWidth = (int) getResources().getDimension(R.dimen.flexible_space_image_height) ;
mlinearLayoutManagerForDateList.scrollToPosition(Integer.MAX_VALUE / 2);
mDateAdapter=new DateAdapter(mWeekDaysList);
listView.setAdapter(mDateAdapter);
mCenterIndicator.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
int center = ( mCenterIndicator.getLeft() + mCenterIndicator.getRight() ) / 2 ;
int padding = center - itemWidth / 2; //Assuming both left and right padding needed are the same
listView.setPadding(5,0,5,0);
mCenterPivot = center;
listView.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
LinearLayoutManager lm = (LinearLayoutManager) recyclerView.getLayoutManager();
if( mCenterPivot == 0 ) {
// Default pivot , Its a bit inaccurate .
// Better pass the center pivot as your Center Indicator view's
// calculated center on it OnGlobalLayoutListener event
mCenterPivot = lm.getOrientation() == LinearLayoutManager.HORIZONTAL ? ( recyclerView.getLeft() + recyclerView.getRight() ) : ( recyclerView.getTop() + recyclerView.getBottom() );
}
if( !mAutoSet ) {
if( newState == RecyclerView.SCROLL_STATE_IDLE ) {
//ScrollStoppped
View view = findCenterView(lm);//get the view nearest to center
//view.setBackgroundColor(Color.RED);
int position = recyclerView.getChildAdapterPosition(view) % mWeekDaysList.size();
Log.d("isideScroll",mWeekDaysList.get(position));
mDateAdapter.setSelecteditem(position);
int viewCenter = lm.getOrientation() == LinearLayoutManager.HORIZONTAL ? ( view.getLeft() + view.getRight() )/2 :( view.getTop() + view.getBottom() )/2;
//compute scroll from center
int scrollNeeded = viewCenter - mCenterPivot; // Add or subtract any offsets you need here
if( lm.getOrientation() == LinearLayoutManager.HORIZONTAL ) {
recyclerView.smoothScrollBy(scrollNeeded, 0);
}
else
{
recyclerView.smoothScrollBy(0, (int) (scrollNeeded));
}
mAutoSet =true;
}
}
if( newState == RecyclerView.SCROLL_STATE_DRAGGING || newState == RecyclerView.SCROLL_STATE_SETTLING ){
mAutoSet =false;
}
}
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
}
});
}
});
return returnView;
}
private void scrollToCenter(View v) {
int itemToScroll = listView.getChildAdapterPosition(v);
int centerOfScreen = listView.getWidth() / 2 - v.getWidth() / 2;
//v.setBackgroundColor(Color.RED);
mlinearLayoutManagerForDateList.scrollToPositionWithOffset(itemToScroll, centerOfScreen);
}
private View findCenterView(LinearLayoutManager lm) {
int minDistance = 0;
View view = null;
View returnView = null;
boolean notFound = true;
for(int i = lm.findFirstVisibleItemPosition(); i <= lm.findLastVisibleItemPosition() && notFound ; i++ ) {
view=lm.findViewByPosition(i);
int center = lm.getOrientation() == LinearLayoutManager.HORIZONTAL ? ( view.getLeft() + view.getRight() )/ 2 : ( view.getTop() + view.getBottom() )/ 2;
int leastDifference = Math.abs(mCenterPivot - center);
if( leastDifference <= minDistance || i == lm.findFirstVisibleItemPosition())
{
minDistance = leastDifference;
returnView=view;
}
else
{
notFound=false;
}
}
return returnView;
}
}
公共类示例扩展了片段{
回收视图列表视图；
ArrayListWeekdaysList=新建ArrayList（）；
直线布局经理MLINEARLAYOUT MANAGERFORDATELIST；
日期适配器mDateAdapter；
TimeListAdapter mtimeAdapter；
私人互联网中心；
私有布尔mAutoSet=true；
活动能力；
公共NigaichiNiralFrag（）{
//必需的空公共构造函数
}
@凌驾
创建视图（最终布局）上的公共视图充气机、视图组容器、，
Bundle savedInstanceState）{
//为该碎片膨胀布局
视图=充气机。充气（R.layout.fragment\u nigaichi\u niral，容器，假）；
mactivity=getActivity（）；
mWeekDaysList.add（“星期日”）；
mWeekDaysList.add（“星期一”）；
mWeekDaysList.add（“星期二”）；
mWeekDaysList.add（“星期三”）；
mWeekDaysList.add（“星期四”）；
mWeekDaysList.add（“星期五”）；
mWeekDaysList.add（“星期六”）；
listView=（RecycleService）view.FindView wByd（R.id.list）；
mlinearLayoutManagerForDateList=新的线性布局管理器（mactivity）；
mlinearLayoutManagerForDateList.setOrientation（LinearLayoutManager.HORIZONTAL）；
setLayoutManager（mlinearLayoutManagerForDateList）；
最终TextView mCenterIndicator=（TextView）view.findViewById（R.id.centerIndicator）；
final int itemWidth=（int）getResources（）.getDimension（R.dimen.flexible\u space\u image\u height）；
mlinearLayoutManagerForDateList.scrollToPosition（Integer.MAX_值/2）；
mDateAdapter=newdateadapter（mWeekDaysList）；
setAdapter（mDateAdapter）；
mCenterIndicator.getViewTreeObserver（）.addOnGlobalLayoutListener（新ViewTreeObserver.OnGlobalLayoutListener（））{
@凌驾
公共图书馆{
int center=（mCenterIndicator.getLeft（）+mCenterIndicator.getRight（））/2；
int padding=center-itemWidth/2；//假设所需的左、右填充相同
setPadding（5,0,5,0）；
mcenterpoint=中心；
listView.addOnScrollListener（新的RecyclerView.OnScrollListener（）{
@凌驾
CrollStateChanged上的公共无效（RecyclerView RecyclerView，int newState）{
super.onScrollStateChanged（recyclerView、newState）；
LinearLayoutManager lm=（LinearLayoutManager）recyclerView.getLayoutManager（）；
如果（mCenterPivot==0）{
//默认轴，有点不准确。
//最好将中心轴作为中心指示器视图的
//LobalLayoutListener事件上的计算中心
mcenterpoint=lm.getOrientation（）==LinearLayoutManager.HORIZONTAL？（recyclerView.getLeft（）+recyclerView.getRight（））：（recyclerView.getTop（）+recyclerView.getBottom（））；
}
if（！mAutoSet）{
if（newState==RecyclerView.SCROLL\u STATE\u IDLE）{
//滚动停止
视图=FindCenter视图（lm）；//获取最靠近中心的视图
//视图.setBackgroundColor（颜色.红色）；
int position=recyclerView.getChildAdapterPosition（视图）%mWeekDaysList.size（）；
Log.d（“isideScroll”，mWeekDaysList.get（position））；
mDateAdapter.setSelecteditem（位置）；
int viewCenter=lm.getOrientation（）==LinearLayoutManager.HORIZONTAL？（view.getLeft（）+view.getRight（））/2:（view.getTop（）+view.getBottom（））/2；
//从中心开始计算滚动
int scrollNeeded=viewCenter-mcenterpoint；//在此处添加或减去所需的任何偏移量
if（lm.getOrientation（）==LinearLayoutManager.HORIZONTAL）{
recyclerView.smoothScrollBy（ScrollRequired，0）；
}
其他的
{
smoothScrollBy（0，（int）（ScrollRequired））；
}
mAutoSet=true；
}
}
if（newState==RecyclerView.SCROLL_STATE_拖动| | newState==RecyclerView.SCROLL_STATE_结算）{
mAutoSet=false；
}
}
@凌驾
已填空的公共空间（RecyclerView RecyclerView、int dx、int dy）{
super.onScrolled（recyclerView、dx、dy）；
}
});
}
});
返回视图；
}
私有无效滚动中心（视图v）{
int itemToScroll=listView.getChildAdapterPosition（v）；
int centerOfScreen=listView.getWidth（）/2-v.getWidth（）/2；
//v、 setBackgroundColor（颜色：红色）；
mlinearLayoutManagerForDateList.scrollToPositionWithOffset（itemToScroll，屏幕中心）；
}
私有视图FindCenter视图（LinearLayoutManager lm）{
智力距离=0；
By using center indicator(textview) in the layout and addOnScrollListner we can achieve this
please refer the following example
<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"
>
<TextView
android:layout_width="wrap_content"
android:text="↓"
android:id="@+id/centerIndicator"
android:textSize="24sp"
android:textStyle="bold"
android:visibility="visible"
android:textColor="@color/theme_yellow"
android:layout_centerHorizontal="true"
android:layout_height="wrap_content"
android:layout_marginTop="27dp"
android:background="@android:color/transparent"
/>
<android.support.v7.widget.RecyclerView
android:layout_width="match_parent"
android:id="@+id/list"
android:clipToPadding="false"
android:divider="@android:color/transparent"
android:layout_height="wrap_content"/>
</RelativeLayout>
public class Sample extends Fragment {
RecyclerView listView;
ArrayList<String>mWeekDaysList=new ArrayList<>();
LinearLayoutManager mlinearLayoutManagerForDateList;
DateAdapter mDateAdapter;
TimeListAdapter mtimeAdapter;
private int mCenterPivot;
private boolean mAutoSet = true;
Activity mactivity;
public NigaichiNiralFrag() {
// Required empty public constructor
}
@Override
public View onCreateView(final LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view= inflater.inflate(R.layout.fragment_nigaichi_niral, container, false);
mactivity=getActivity();
mWeekDaysList.add("Sunday");
mWeekDaysList.add("Monday");
mWeekDaysList.add("Tuesday");
mWeekDaysList.add("Wednesday");
mWeekDaysList.add("Thursday");
mWeekDaysList.add("Friday");
mWeekDaysList.add("Saturday");
listView = (RecyclerView) view.findViewById(R.id.list);
mlinearLayoutManagerForDateList = new LinearLayoutManager(mactivity);
mlinearLayoutManagerForDateList.setOrientation(LinearLayoutManager.HORIZONTAL);
listView.setLayoutManager(mlinearLayoutManagerForDateList);
final TextView mCenterIndicator = (TextView) view.findViewById(R.id.centerIndicator);
final int itemWidth = (int) getResources().getDimension(R.dimen.flexible_space_image_height) ;
mlinearLayoutManagerForDateList.scrollToPosition(Integer.MAX_VALUE / 2);
mDateAdapter=new DateAdapter(mWeekDaysList);
listView.setAdapter(mDateAdapter);
mCenterIndicator.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
int center = ( mCenterIndicator.getLeft() + mCenterIndicator.getRight() ) / 2 ;
int padding = center - itemWidth / 2; //Assuming both left and right padding needed are the same
listView.setPadding(5,0,5,0);
mCenterPivot = center;
listView.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
LinearLayoutManager lm = (LinearLayoutManager) recyclerView.getLayoutManager();
if( mCenterPivot == 0 ) {
// Default pivot , Its a bit inaccurate .
// Better pass the center pivot as your Center Indicator view's
// calculated center on it OnGlobalLayoutListener event
mCenterPivot = lm.getOrientation() == LinearLayoutManager.HORIZONTAL ? ( recyclerView.getLeft() + recyclerView.getRight() ) : ( recyclerView.getTop() + recyclerView.getBottom() );
}
if( !mAutoSet ) {
if( newState == RecyclerView.SCROLL_STATE_IDLE ) {
//ScrollStoppped
View view = findCenterView(lm);//get the view nearest to center
//view.setBackgroundColor(Color.RED);
int position = recyclerView.getChildAdapterPosition(view) % mWeekDaysList.size();
Log.d("isideScroll",mWeekDaysList.get(position));
mDateAdapter.setSelecteditem(position);
int viewCenter = lm.getOrientation() == LinearLayoutManager.HORIZONTAL ? ( view.getLeft() + view.getRight() )/2 :( view.getTop() + view.getBottom() )/2;
//compute scroll from center
int scrollNeeded = viewCenter - mCenterPivot; // Add or subtract any offsets you need here
if( lm.getOrientation() == LinearLayoutManager.HORIZONTAL ) {
recyclerView.smoothScrollBy(scrollNeeded, 0);
}
else
{
recyclerView.smoothScrollBy(0, (int) (scrollNeeded));
}
mAutoSet =true;
}
}
if( newState == RecyclerView.SCROLL_STATE_DRAGGING || newState == RecyclerView.SCROLL_STATE_SETTLING ){
mAutoSet =false;
}
}
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
}
});
}
});
return returnView;
}
private void scrollToCenter(View v) {
int itemToScroll = listView.getChildAdapterPosition(v);
int centerOfScreen = listView.getWidth() / 2 - v.getWidth() / 2;
//v.setBackgroundColor(Color.RED);
mlinearLayoutManagerForDateList.scrollToPositionWithOffset(itemToScroll, centerOfScreen);
}
private View findCenterView(LinearLayoutManager lm) {
int minDistance = 0;
View view = null;
View returnView = null;
boolean notFound = true;
for(int i = lm.findFirstVisibleItemPosition(); i <= lm.findLastVisibleItemPosition() && notFound ; i++ ) {
view=lm.findViewByPosition(i);
int center = lm.getOrientation() == LinearLayoutManager.HORIZONTAL ? ( view.getLeft() + view.getRight() )/ 2 : ( view.getTop() + view.getBottom() )/ 2;
int leastDifference = Math.abs(mCenterPivot - center);
if( leastDifference <= minDistance || i == lm.findFirstVisibleItemPosition())
{
minDistance = leastDifference;
returnView=view;
}
else
{
notFound=false;
}
}
return returnView;
}
}
public class DateAdapter extends RecyclerView.Adapter<DateAdapter.ReviewHolder> {
ArrayList<String> mData;
private int selectedItem = -1;
int pos=0;
public DateAdapter(ArrayList<String> data){
mData=data;
}
@Override
public ReviewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
Context context = parent.getContext();
View v= LayoutInflater.from(context).inflate(R.layout.item_horz,parent,false);
return new DateAdapter.ReviewHolder(v);
}
@Override
public void onBindViewHolder(ReviewHolder holder, int position) {
pos=position;
position = position % mData.size();
holder.tvName.setText(mData.get(position));
holder.tvName.setGravity(Gravity.CENTER);
if (position == selectedItem) {
Log.d("CenterPosition", "center" + position);
holder.tvName.setTextColor(Color.RED);
holder.tvName.setTextSize(20);
holder.tvName.setBackgroundColor(Color.parseColor("#fccd00"));
} else {
holder.tvName.setTextColor(Color.WHITE);
holder.tvName.setTextSize(16);
holder.tvName.setBackgroundColor(Color.BLACK);
}
}
@Override
public int getItemCount() {
// return mData.size();
return Integer.MAX_VALUE;
}
public class ReviewHolder extends RecyclerView.ViewHolder {
protected TextView tvName;
View container;
public ReviewHolder(View itemView) {
super(itemView);
container=itemView;
tvName= (TextView) itemView.findViewById(R.id.text);
}
}
public void setSelecteditem(int selecteditem) {
Log.d("POSITION",String.valueOf(selecteditem));
this.selectedItem = selecteditem;
notifyDataSetChanged();
}
}
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="151dp"
android:id="@+id/wrapper"
android:background="@color/white"
android:orientation="horizontal"
android:layout_height="50dp">
<LinearLayout
android:layout_width="150dp"
android:layout_height="50dp"
android:background="@color/black">
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:textSize="20sp"
android:id="@+id/text"
android:textColor="@color/white"
android:text="21"
android:gravity="center"
/>
</LinearLayout>
</LinearLayout>