i have created a circular recyclerview by making adapter count into Integer.MAX.Now, i need to highlight the center recycler item like in the image.Kindly help me!!
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Darsy
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Interesting concept, trying to highlight the centre of something infinite. ;) I think you can try to get the first and last visible items and deduce the centre from that. See: https://stackoverflow.com/a/25053500/1827254 – Eselfar Jul 19 '17 at 12:32
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this can be your answer . see link .https://stackoverflow.com/a/39191696/6155031 – 6155031 Jul 19 '17 at 13:04
4 Answers
1
if you want to use horizontalscrollview (create items dynamically)instead recyclerview.
create your parent layout
<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>
inflate your childs items to parent layout.
LayoutInflater inflater = (LayoutInflater) getActivity().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
for (int i = 0; i < list.size(); i++) {
// inflate child element
final LinearLayout titleRow = (LinearLayout) inflater.inflate(R.layout.item_gallery, fragmentGalleryScrollLl, false);
final CircleImageView shapeImageView = (CircleImageView) titleRow.findViewById(R.id.item_gallery_iv);
shapeImageView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
scrollItem(titleRow);
}
});
fragmentGalleryScrollLl.addView(titleRow);
}
use this method when your click the items.
private void scrollItem(LinearLayout titleRow) {
int scrollX = (titleRow.getLeft() - (fragmentGalleryScrollSv.getWidth() / 2)) + (titleRow.getWidth() / 2);
fragmentGalleryScrollSv.smoothScrollTo(scrollX, 0);
}
6155031
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1
By using center indicator(textview) in the layout and addOnScrollListner we can achieve this
please refer the following example
In xml:
<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>
In Activity/Fragment:
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;
}
}
Adapter:
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();
}
}
item_horz.xml
<?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>
Hope this will help you guys..
vignesh muthuraman
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Inside BindView, you can check middle position of the adapter and apply logic for image for that specific holder.
onBindViewHolder(View holder, int postion){
if(position == getItemCount() / 2)
{ //Write image logic for holder
}}
GAGAN BHATIA
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its not working because adapter size is infinite .. it will give IndexOutOfboundexception – Darsy Jul 19 '17 at 12:53
0
Callback to get center item position when scrolling stopped
import android.content.Context
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
class RecyclerCenterItemFinder(
private val context: Context,
private val layoutManager: LinearLayoutManager,
private val callback: (Int) -> Unit,
private val controlState: Int = RecyclerView.SCROLL_STATE_IDLE
) :
RecyclerView.OnScrollListener() {
override fun onScrollStateChanged(recyclerView: RecyclerView, newState: Int) {
if (controlState == ALL_STATES || newState == controlState) {
val firstVisible = layoutManager.findFirstVisibleItemPosition()
val lastVisible = layoutManager.findLastVisibleItemPosition()
val itemsCount = lastVisible - firstVisible + 1
val screenCenter: Int = context.resources.displayMetrics.widthPixels / 2
var minCenterOffset = Int.MAX_VALUE
var middleItemIndex = 0
for (index in 0 until itemsCount) {
val listItem = layoutManager.getChildAt(index) ?: return
val topOffset = listItem.top
val bottomOffset = listItem.bottom
val centerOffset =
Math.abs(topOffset - screenCenter) + Math.abs(bottomOffset - screenCenter)
if (minCenterOffset > centerOffset) {
minCenterOffset = centerOffset
middleItemIndex = index + firstVisible
}
}
callback(middleItemIndex)
}
}
companion object {
const val ALL_STATES = 10
}
}
recycler.addOnScrollListener(RecyclerCenterItemFinder(requireContext(),
recycler.layoutManager,
{ centerItemPosition ->
// do something
}
))
Omkar T
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