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CardViewPager.java
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CardViewPager.java
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import android.content.Context;
import android.support.annotation.Nullable;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.ViewGroup;
import java.lang.ref.WeakReference;
/**
* Created by izhaowo on 2016/6/2.
*/
public class CardViewPager extends RecyclerView {
WrapperAdapter wrapperAdapter;
/**
* item间距的像素
*/
int itemPadding = 0;
private int scrolled = 0;
int mMinFlingVelocity;
public CardViewPager(Context context) {
super(context);
init(context);
}
public CardViewPager(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
init(context);
}
public CardViewPager(Context context, @Nullable AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init(context);
}
boolean innerScroll = false;
private void init(Context context) {
if(isInEditMode()){return;}
ViewConfiguration vc = ViewConfiguration.get(context);
mMinFlingVelocity = vc.getScaledMinimumFlingVelocity();
setOverScrollMode(OVER_SCROLL_NEVER);
setLayoutManager(new LinearLayoutManager(context, LinearLayoutManager.HORIZONTAL, false));
setWrapperAdapter(new WrapperAdapter(this, defaultCardAdapter));
addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
scrolled += dx;
}
@Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
switch (newState){
case RecyclerView.SCROLL_STATE_DRAGGING:{
innerScroll = false;
break;
}
case RecyclerView.SCROLL_STATE_IDLE:{
if (innerScroll) {
View currentCenterView = getCenterChild();
if (currentCenterView == null){return;}
final LayoutManager layoutManager = getLayoutManager();
final int currentPosition = layoutManager.getPosition(currentCenterView);
wrapperAdapter.onPageChanged(currentPosition);
}
break;
}
case RecyclerView.SCROLL_STATE_SETTLING:{
break;
}
}
}
});
}
@Override
public void stopNestedScroll() {
super.stopNestedScroll();
if(!innerScroll){
scrollToCard(0);
}
}
private void scrollToCard(int pageOffset){
View currentCenterView = getCenterChild();
if (currentCenterView == null){return;}
final LayoutManager layoutManager = getLayoutManager();
final int currentPosition = layoutManager.getPosition(currentCenterView);
if(currentPosition == 0 && pageOffset < 0){
scrollToCard(0);
return;
}
final int itemCount = wrapperAdapter.getItemCount();
if(currentPosition == itemCount - 1 && pageOffset > 0){
scrollToCard(itemCount - 1);
return;
}
final int targetPosition = currentPosition + pageOffset;
float left = 0;
for(int i= 0; i < targetPosition; i++){
left += wrapperAdapter.getItemWidth(i);
}
final int toLeft = (int) (left * getWidth() + targetPosition * getItemPadding());
final int toCenter = (int) (toLeft + (getWidth() * wrapperAdapter.getItemWidth(targetPosition)) * .5f);// + getItemPadding()
innerScroll = true;
smoothScrollBy((int) (toCenter - scrolled - getWidth() * .5f), 0);
}
@Nullable
private View getCenterChild() {
final int halfPadding = (int) (getItemPadding() * .5f);
final float center = getWidth() * .5f;
final int childCount = getChildCount();
for(int i = childCount-1; i >= 0; i--){
final View childAt = getChildAt(i);
if(childAt == null){continue;}
final int left = childAt.getLeft() - halfPadding;
final int right = childAt.getRight() + halfPadding;
if(left <= center && right >= center){
return childAt;
}
}
return null;
}
public void scrollTo(View view) {
float centerView = (view.getLeft() + view.getRight()) * 0.5f;
final int width = getWidth();
innerScroll = true;
smoothScrollBy(-(int) (width*.5f - centerView), 0);
}
@Override
public boolean fling(int velocityX, int velocityY) {
if(isLayoutFrozen()){return false;}
LayoutManager layoutManager = getLayoutManager();
if(layoutManager == null){return false;}
final boolean canScrollHorizontal = layoutManager.canScrollHorizontally();
if(!canScrollHorizontal || Math.abs(velocityX) < mMinFlingVelocity ){return false;}
if(velocityX < 0){
scrollToCard(-1);
}else{
scrollToCard(1);
}
return true;
}
public int getItemPadding() {
return itemPadding;
}
public void setItemPadding(int itemPadding) {
this.itemPadding = itemPadding;
wrapperAdapter.notifyDataSetChanged();
}
private void setWrapperAdapter(WrapperAdapter adapter) {
super.setAdapter(wrapperAdapter = adapter);
}
@Override
public void setAdapter(Adapter adapter) {
if(adapter instanceof CardAdapter){
setAdapter((CardAdapter)adapter);
}else{
throw new IllegalArgumentException("Adapter should instanceof CardAdapter");
}
}
public void setAdapter(CardAdapter adapter) {
wrapperAdapter.setAdapter(adapter);
}
public static abstract class CardAdapter extends Adapter{
public float getItemWidth() {
return 0.8f;
}
public void onPageChanged(int position){}
}
private static CardAdapter defaultCardAdapter = new CardAdapter(){
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
return null;
}
@Override
public void onBindViewHolder(ViewHolder holder, int position) {}
@Override
public int getItemCount() {
return 0;
}
};
private static class WrapperAdapter extends Adapter{
static final int VIEW_TYPE_PH_RIGHT = 1000, VIEW_TYPE_PH_LEFT = 1001,
VIEW_TYPE_EMPTY = 1003;
CardAdapter adapter;
WeakReference<CardViewPager> viewPager;
AdapterDataObserver wrapObserver = new AdapterDataObserver() {
@Override
public void onChanged() {
notifyDataSetChanged();
}
@Override
public void onItemRangeChanged(int positionStart, int itemCount) {
notifyItemRangeChanged(positionStart+1, itemCount);
}
@Override
public void onItemRangeChanged(int positionStart, int itemCount, Object payload) {
notifyItemRangeChanged(positionStart+1, itemCount, payload);
}
@Override
public void onItemRangeInserted(int positionStart, int itemCount) {
notifyItemRangeInserted(positionStart+1, itemCount);
}
@Override
public void onItemRangeRemoved(int positionStart, int itemCount) {
notifyItemRangeRemoved(positionStart+1, itemCount);
}
@Override
public void onItemRangeMoved(int fromPosition, int toPosition, int itemCount) {
for(int i=0;i<itemCount;i++){
notifyItemMoved(fromPosition+1+i, toPosition+1+i);
}
}
};
public WrapperAdapter(CardViewPager viewPager, CardAdapter adapter) {
this.viewPager = new WeakReference<>(viewPager);
// this.adapter = adapter;
setAdapter(adapter);
}
public void setAdapter(CardAdapter adapter) {
if(this.adapter != null){
this.adapter.unregisterAdapterDataObserver(wrapObserver);
}
this.adapter = adapter;
if(adapter != null){
adapter.registerAdapterDataObserver(wrapObserver);
}else{
setAdapter(defaultCardAdapter);
return;
}
notifyDataSetChanged();
}
public void onPageChanged(int position){
if(position == 0 || position == getItemCount() - 1){return;}
this.adapter.onPageChanged(position - 1);
}
public float getItemWidth(int position) {
if(getRealCount() == 0){
if(position == 0 || position == getItemCount() - 1){
return 0.3f;
}
return 0.4f;
}
if(position == 0 || position == getItemCount() - 1){
final CardViewPager cardViewPager = viewPager.get();
final float padding = (1f * cardViewPager.getItemPadding() / cardViewPager.getWidth());
return (1f - adapter.getItemWidth() - padding * 2) * .5f;
}
return adapter.getItemWidth();
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
CardViewPager cardViewPager = (CardViewPager) parent;
final int hanlfPadding = (int) (cardViewPager.getItemPadding() * .5f);
switch (viewType){
case VIEW_TYPE_PH_LEFT:{
final int width = parent.getWidth();
final ViewHolder viewHolder = makeViewHolder(parent);
setWidth(viewHolder, (int) (getItemWidth(0) * width));
setMarginLR(viewHolder, 0, hanlfPadding);
return viewHolder;
}
case VIEW_TYPE_PH_RIGHT:{
final int width = parent.getWidth();
final ViewHolder viewHolder = makeViewHolder(parent);
setWidth(viewHolder, (int) (getItemWidth(0) * width));
setMarginLR(viewHolder, hanlfPadding, 0);
return viewHolder;
}
default:{
// case VIEW_TYPE_ITEM:{
final int width = parent.getWidth();
final ViewHolder viewHolder = adapter.onCreateViewHolder(parent, viewType);
setWidth(viewHolder, (int) (width * adapter.getItemWidth()));
setMarginLR(viewHolder, hanlfPadding, hanlfPadding);
return viewHolder;
}
case VIEW_TYPE_EMPTY:{
final int width = parent.getWidth();
final ViewHolder viewHolder = makeViewHolder(parent);
setWidth(viewHolder, (int) (width * getItemWidth(1)));
setMarginLR(viewHolder, hanlfPadding, hanlfPadding);
return viewHolder;
}
}
}
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
int viewType = getItemViewType(position);
switch (viewType) {
case VIEW_TYPE_PH_LEFT: {
CardViewPager viewPager = this.viewPager.get();
setWidth(holder, (int) (getItemWidth(0) * viewPager.getWidth()));
break;
}
case VIEW_TYPE_PH_RIGHT: {
CardViewPager viewPager = this.viewPager.get();
setWidth(holder, (int) (getItemWidth(0) * viewPager.getWidth()));
break;
}
default: {
// case VIEW_TYPE_ITEM:{
CardViewPager viewPager = this.viewPager.get();
setWidth(holder, (int) (viewPager.getWidth() * adapter.getItemWidth()));
break;
}
case VIEW_TYPE_EMPTY: {
CardViewPager viewPager = this.viewPager.get();
setWidth(holder, (int) (viewPager.getWidth() * adapter.getItemWidth()));
break;
}
}
switch (viewType){
case VIEW_TYPE_PH_RIGHT:
case VIEW_TYPE_PH_LEFT:
case VIEW_TYPE_EMPTY:{
break;
}
default:{
adapter.onBindViewHolder(holder, position - 1);
break;
}
}
}
@Override
public int getItemCount() {
final int realCount = getRealCount();
return 2 + (realCount == 0 ? 1 : realCount);
}
@Override
public int getItemViewType(int position) {
if(position == 0){return VIEW_TYPE_PH_LEFT;}
if(position == getItemCount() - 1){return VIEW_TYPE_PH_RIGHT;}
if(getRealCount() == 0){return VIEW_TYPE_EMPTY;}
return adapter.getItemViewType(position - 1);
}
private int getRealCount() {
return adapter == null ? 0 : adapter.getItemCount();
}
}
//=========
public static void setWidth(ViewHolder viewHolder, int width) {
final View itemView = viewHolder.itemView;
ensureLayoutParams(viewHolder);
final RecyclerView.LayoutParams layoutParams = (LayoutParams) itemView.getLayoutParams();
layoutParams.width = width;
itemView.setLayoutParams(layoutParams);
}
public static void setHeight(ViewHolder viewHolder, int height) {
final View itemView = viewHolder.itemView;
ensureLayoutParams(viewHolder);
final RecyclerView.LayoutParams layoutParams = (LayoutParams) itemView.getLayoutParams();
layoutParams.height = height;
itemView.setLayoutParams(layoutParams);
}
public static void setMarginLR(ViewHolder viewHolder, int left, int right) {
final View itemView = viewHolder.itemView;
ensureLayoutParams(viewHolder);
final RecyclerView.LayoutParams layoutParams = (LayoutParams) itemView.getLayoutParams();
layoutParams.leftMargin = left;
layoutParams.rightMargin = right;
itemView.setLayoutParams(layoutParams);
}
public static void setMarginTB(ViewHolder viewHolder, int top, int bottom) {
final View itemView = viewHolder.itemView;
ensureLayoutParams(viewHolder);
final RecyclerView.LayoutParams layoutParams = (LayoutParams) itemView.getLayoutParams();
layoutParams.topMargin = top;
layoutParams.bottomMargin = bottom;
itemView.setLayoutParams(layoutParams);
}
private static void ensureLayoutParams(ViewHolder holder) {
ViewGroup.LayoutParams layoutParams = holder.itemView.getLayoutParams();
if(layoutParams == null || !(layoutParams instanceof RecyclerView.LayoutParams)){
holder.itemView.setLayoutParams(new RecyclerView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
ViewGroup.LayoutParams.MATCH_PARENT));
}
}
public static ViewHolder makeViewHolder(ViewGroup parent) {
final ViewHolder viewHolder = new ViewHolder(makeView(parent)) {};
return viewHolder;
}
public static View makeView(ViewGroup parent) {
View view = new View(parent.getContext());
view.setLayoutParams(new RecyclerView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
return view;
}
}