package com.ypx.imagepicker.helper;
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import android.animation.ValueAnimator;
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import androidx.annotation.NonNull;
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import androidx.recyclerview.widget.GridLayoutManager;
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import androidx.recyclerview.widget.RecyclerView;
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import android.view.View;
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import android.view.animation.AccelerateDecelerateInterpolator;
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import com.ypx.imagepicker.utils.PViewSizeUtils;
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import com.ypx.imagepicker.widget.TouchRecyclerView;
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/**
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* Description: 滑动辅助类
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* <p>
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* Author: peixing.yang
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* Date: 2019/2/26
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*/
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public class RecyclerViewTouchHelper {
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private TouchRecyclerView recyclerView;
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private View topView;
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private View maskView;
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private boolean isScrollTopView = false;
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private boolean isTopViewStick = false;
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private int canScrollHeight;
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private int stickHeight;
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public static RecyclerViewTouchHelper create(TouchRecyclerView recyclerView) {
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return new RecyclerViewTouchHelper(recyclerView);
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}
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private RecyclerViewTouchHelper(TouchRecyclerView recyclerView) {
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this.recyclerView = recyclerView;
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}
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public RecyclerViewTouchHelper setTopView(View topView) {
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this.topView = topView;
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return this;
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}
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public RecyclerViewTouchHelper setMaskView(View maskView) {
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this.maskView = maskView;
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return this;
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}
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public RecyclerViewTouchHelper setCanScrollHeight(int canScrollHeight) {
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this.canScrollHeight = canScrollHeight;
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return this;
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}
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public RecyclerViewTouchHelper setStickHeight(int stickHeight) {
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this.stickHeight = stickHeight;
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return this;
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}
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private void setRecyclerViewPaddingTop(int top) {
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recyclerView.setPadding(recyclerView.getPaddingStart(), top,
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recyclerView.getPaddingEnd(), recyclerView.getPaddingBottom());
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}
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private int lastScrollY = 0;
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public RecyclerViewTouchHelper build() {
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setRecyclerViewPaddingTop(canScrollHeight + stickHeight);
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recyclerView.post(new Runnable() {
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@Override
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public void run() {
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setRecyclerViewPaddingTop(topView.getHeight());
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}
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});
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recyclerView.setTouchView(topView);
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recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
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@Override
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public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
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super.onScrolled(recyclerView, dx, dy);
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if (isImageGridCantScroll()) {
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return;
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}
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int scrollY = getScrollYDistance();
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if (isScrollTopView && topView.getTranslationY() != -canScrollHeight) {
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if (lastScrollY == 0) {
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lastScrollY = scrollY;
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}
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int distance = scrollY - lastScrollY;
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if (distance >= canScrollHeight) {
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setMaskAlpha(1);
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topView.setTranslationY(-canScrollHeight);
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setRecyclerViewPaddingTop(stickHeight);
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} else {
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if (distance <= 0) {
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setMaskAlpha(0);
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topView.setTranslationY(0);
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} else {
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float ratio = -distance * 1.00f / (-canScrollHeight * 1.00f);
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setMaskAlpha(ratio);
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topView.setTranslationY(-distance);
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}
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}
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return;
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}
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if (isTopViewFullShow()) {
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isTopViewStick = false;
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setMaskAlpha(0);
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}
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if (isTopViewStick) {
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int translate = -scrollY - topView.getHeight();
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if (translate <= -canScrollHeight) {
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topView.setTranslationY(-canScrollHeight);
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setRecyclerViewPaddingTop(stickHeight);
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isTopViewStick = false;
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} else {
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if (translate >= -20) {
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translate = 0;
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}
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topView.setTranslationY(translate);
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float ratio = topView.getTranslationY() * 1.00f / (-topView.getHeight() * 1.00f);
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setMaskAlpha(ratio);
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}
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}
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}
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});
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recyclerView.setDragScrollListener(new TouchRecyclerView.onDragScrollListener() {
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@Override
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public void onScrollOverTop(int distance) {
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if (isImageGridCantScroll()) {
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return;
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}
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isScrollTopView = true;
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}
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@Override
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public void onScrollDown(int distance) {
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if (isImageGridCantScroll()) {
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return;
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}
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if (isRecyclerViewScrollToTop() && !isScrollTopView) {
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setRecyclerViewPaddingTop(topView.getHeight());
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isTopViewStick = true;
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}
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}
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@Override
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public void onScrollUp() {
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lastScrollY = 0;
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if (isImageGridCantScroll()) {
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return;
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}
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if (isScrollTopView) {
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transitTopWithAnim(!isRecyclerViewCanScrollOverScreen(), -1, true);
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} else {
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if (isTopViewStick && !isTopViewFullShow()) {
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reset();
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}
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}
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isScrollTopView = false;
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}
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});
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return this;
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}
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private boolean isRecyclerViewScrollToTop() {
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return !recyclerView.canScrollVertically(-1);
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}
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private boolean isRecyclerViewScrollToBottom() {
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return !recyclerView.canScrollVertically(1);
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}
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private boolean isRecyclerViewCanScrollOverScreen() {
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if (isImageGridCantScroll()) {
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return false;
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}
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int count = 0;
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if (recyclerView.getAdapter() != null) {
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count = recyclerView.getAdapter().getItemCount();
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}
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int itemHeight = getItemHeight();
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if (count < getSpanCount()) {
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return false;
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}
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int lineCount = count % getSpanCount() == 0 ? count / getSpanCount() : count / getSpanCount() + 1;
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return lineCount * itemHeight + recyclerView.getPaddingBottom() >
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PViewSizeUtils.getScreenHeight(recyclerView.getContext()) - stickHeight;
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}
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private int spanCount = 0;
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private int getSpanCount() {
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if (spanCount != 0) {
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return spanCount;
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}
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GridLayoutManager gridLayoutManager = (GridLayoutManager) recyclerView.getLayoutManager();
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if (gridLayoutManager != null) {
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spanCount = gridLayoutManager.getSpanCount();
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return spanCount;
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}
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return 0;
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}
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/**
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* 设置剪裁区域阴影
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*
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* @param ratio 阴影比例
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*/
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private void setMaskAlpha(float ratio) {
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maskView.setVisibility(View.VISIBLE);
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if (ratio <= 0) {
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ratio = 0;
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maskView.setVisibility(View.GONE);
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} else if (ratio >= 1) {
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ratio = 1;
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}
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maskView.setAlpha(ratio);
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}
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/**
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* 剪裁区域+标题栏 是否完整显示
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*/
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private boolean isTopViewFullShow() {
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return (topView.getTranslationY() == 0);
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}
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/**
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* 选择图片recyclerView是否不可以滑动（数量少）
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*/
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private boolean isImageGridCantScroll() {
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return !recyclerView.canScrollVertically(1) &&
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!recyclerView.canScrollVertically(-1);
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}
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/**
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* 获取recyclerView滑动距离
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*/
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private int getScrollYDistance() {
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if (!(recyclerView.getLayoutManager() instanceof GridLayoutManager)) {
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return 0;
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}
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GridLayoutManager gridLayoutManager = (GridLayoutManager) recyclerView.getLayoutManager();
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int position = gridLayoutManager.findFirstVisibleItemPosition();
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if (position < 0) {
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position = 0;
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}
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View firstVisibleChildView = gridLayoutManager.findViewByPosition(position);
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if (firstVisibleChildView == null) {
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return 0;
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}
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int itemHeight = firstVisibleChildView.getHeight() + PViewSizeUtils.dp(recyclerView.getContext(), 2);
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return (position / getSpanCount()) * itemHeight - firstVisibleChildView.getTop();
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}
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private int getItemHeight() {
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if (!(recyclerView.getLayoutManager() instanceof GridLayoutManager)) {
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return 0;
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}
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GridLayoutManager gridLayoutManager = (GridLayoutManager) recyclerView.getLayoutManager();
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int position = gridLayoutManager.findFirstVisibleItemPosition();
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if (position < 0) {
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position = 0;
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}
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View firstVisibleChildView = gridLayoutManager.findViewByPosition(position);
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if (firstVisibleChildView == null) {
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return 0;
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}
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return firstVisibleChildView.getHeight();
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}
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private void reset() {
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final int scrollY = getScrollYDistance();
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if (scrollY == 0) {
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return;
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}
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ValueAnimator anim = ValueAnimator.ofFloat(0.0f, 1.0f);
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anim.setDuration(500);
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anim.setInterpolator(new AccelerateDecelerateInterpolator());
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anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
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@Override
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public void onAnimationUpdate(ValueAnimator animation) {
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float ratio = (Float) animation.getAnimatedValue();
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recyclerView.scrollBy(0, (int) (scrollY * ratio));
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}
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});
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anim.start();
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}
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/**
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* 动画控制是否展开还是完整显示topView
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*
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* @param isFocusShow 是否强制完全展示
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* @param scrollToPosition 滑动到制定的位置
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*/
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public void transitTopWithAnim(boolean isFocusShow, final int scrollToPosition, boolean isShowTransit) {
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if (!isShowTransit) {
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return;
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}
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if (isTopViewFullShow()) {
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return;
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}
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final int startTop = (int) topView.getTranslationY();
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//如果滑动区域小于标题栏高度的一半，则完全展示，否则收回剪裁区域到顶部
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final int endTop = (isFocusShow || (startTop > -stickHeight / 2)) ? 0 : -canScrollHeight;
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final int startPadding = recyclerView.getPaddingTop();
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final float startAlpha = maskView.getAlpha();
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ValueAnimator anim = ValueAnimator.ofFloat(0.0f, 1.0f);
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anim.setDuration(300);
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anim.setInterpolator(new AccelerateDecelerateInterpolator());
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anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
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@Override
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public void onAnimationUpdate(ValueAnimator animation) {
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float ratio = (Float) animation.getAnimatedValue();
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int dis = (int) ((endTop - startTop) * ratio + startTop);
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topView.setTranslationY(dis);
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float maskAlpha = endTop == 0 ? (-startAlpha) * ratio + startAlpha : (1 - startAlpha) * ratio + startAlpha;
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setMaskAlpha(maskAlpha);
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int padding = (int) (((endTop == 0 ? topView.getHeight() : stickHeight) - startPadding) * ratio + startPadding);
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setRecyclerViewPaddingTop(padding);
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if (ratio == 1.0f) {
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if (scrollToPosition == 0) {
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recyclerView.scrollToPosition(0);
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} else if (scrollToPosition != -1) {
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recyclerView.smoothScrollToPosition(scrollToPosition);
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}
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}
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}
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});
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anim.start();
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}
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public int dp(int dp) {
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return PViewSizeUtils.dp(recyclerView.getContext(), dp);
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}
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}
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