Java Code Examples for android.support.v7.widget.RecyclerView#findViewHolderForAdapterPosition()

/**
 * 同步 parent 的展开折叠状态
 * <p>
 * 如果当前要通知的 parent 未 laid out , 后期当该 parent attach 到 {@link RecyclerView} 时,
 * 会完成同步并回调相关接口
 * </p>
 *
 * @param parentPosition parent 列表项位置
 */
private void syncParentExpandableState(int parentPosition) {
    final int parentAdapterPos = getParentAdapterPosition(parentPosition);
    if (parentAdapterPos == RecyclerView.NO_POSITION) return;
    ItemWrapper itemWrapper = getItem(parentAdapterPos);
    final boolean expandable = itemWrapper.isExpandable();
    Logger.e(TAG, "syncParentExpandableState=>" + parentPosition + "," + expandable);
    for (RecyclerView rv : mAttachedRecyclerViews) {
        ParentViewHolder pvh = (ParentViewHolder) rv
                .findViewHolderForAdapterPosition(parentAdapterPos);
        if (pvh != null && pvh.isExpandable() != expandable) {
            pvh.setExpandable(expandable);
            notifyParentExpandableStateChanged(pvh, expandable);
        } else if (pvh == null) {
            pendingExpandableAdd(rv, parentPosition);
        }
    }
}
 

/**
 * notify item state changed
 */
private void notifyItemExpandedOrCollapsed(int parentIndex, boolean isExpand) {
    if (mRecyclerViewList != null && !mRecyclerViewList.isEmpty()) {
        RecyclerView recyclerView = mRecyclerViewList.get(0);
        BaseAdapterItem viewHolderForAdapterPosition = (BaseAdapterItem) recyclerView.findViewHolderForAdapterPosition(parentIndex);
        try {

            AbstractAdapterItem<Object> item = viewHolderForAdapterPosition.getItem();
            if (item != null && item instanceof AbstractExpandableAdapterItem) {
                AbstractExpandableAdapterItem abstractExpandableAdapterItem = (AbstractExpandableAdapterItem) item;
                abstractExpandableAdapterItem.onExpansionToggled(isExpand);
            }
        } catch (Exception e) {
        }
    }
}
 

@SuppressWarnings("unchecked")
@Override
public void onDragAnimationEnd(RecyclerView recyclerView, int position) {
    VH selectedViewHolder = (VH) recyclerView.findViewHolderForAdapterPosition(position);
    if(selectedViewHolder == null) return;
    onDragAnimationEnd(selectedViewHolder,position);
}
 

@Override
public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
    super.onDrawOver(c, parent, state);
    final int position = ((LinearLayoutManager) parent.getLayoutManager()).findFirstVisibleItemPosition();
    if (position == RecyclerView.NO_POSITION) {
        return;
    }
    View child = parent.findViewHolderForAdapterPosition(position).itemView;
    String initial = getTag(position);
    if (initial == null) {
        return;
    }

    boolean flag = false;
    if (getTag(position + 1) != null && !initial.equals(getTag(position + 1))) {
        if (child.getHeight() + child.getTop() < mTitleHeight) {
            c.save();
            flag = true;
            c.translate(0, child.getHeight() + child.getTop() - mTitleHeight);
        }
    }

    c.drawRect(parent.getPaddingLeft(), parent.getPaddingTop(),
            parent.getRight() - parent.getPaddingRight(), parent.getPaddingTop() + mTitleHeight, mBackgroundPaint);
    c.drawText(initial, child.getPaddingLeft() + mTextStartMargin,
            parent.getPaddingTop() + mTitleHeight - (mTitleHeight - mTextHeight) / 2 - mTextBaselineOffset, mTextPaint);

    if (flag) {
        c.restore();
    }
}
 

@SuppressWarnings("unchecked")
private void syncViewCollapseState(Integer parentPosition, boolean byUser)
{
    Logger.e(TAG, "syncViewCollapseState=>" + parentPosition);
    int parentAdapterPos = getParentAdapterPosition(parentPosition);
    if (parentAdapterPos == RecyclerView.NO_POSITION) return;
    ItemWrapper itemWrapper = getItem(parentAdapterPos);
    boolean collapsed = !itemWrapper.isExpanded();

    for (RecyclerView rv : mAttachedRecyclerViews) {
        PVH pvh = (PVH) rv.findViewHolderForAdapterPosition(parentAdapterPos);
        if (pvh != null && pvh.isExpanded() && collapsed) {
            pvh.setExpanded(false);
            // 通知所有监听 Parent 展开折叠状态监听器当前 Parent 已折叠
            notifyParentCollapsed(pvh, false, byUser);
        } else if (pvh == null && collapsed) {
            // 判断当前的 parent 是否 expandable ,防止记录不可 expandable 的 parent 的待折叠位置信息
            // 当该后期应用该位置的 parent 折叠操作时导致本该应用该位置的 parent 展开操作时被该折叠操作所覆盖问题
            Logger.e(TAG, "collapseViews pvh is null---->parentPos=" + parentPosition +
                          ",parentAdapterPos=" + parentAdapterPos);
            // 未 laid out 的 Parent ,虽然无法获取并设置展开折叠标识，
            // 这里添加待处理折叠逻辑的所有 parentItem 的 position
            // 如果先前已经记录待折叠位置记录，移除该记录并以最新的待展开记录为准!
            pendingExpandRemove(rv, parentPosition);
            pendingCollapseAdd(rv, parentPosition);
        }
    }
}
 

@SuppressWarnings("unchecked")
@Override
public void onStartMergeAnimation(RecyclerView parent, int selectedPosition, int targetPosition,int duration) {
    VH selectedViewHolder = (VH) parent.findViewHolderForAdapterPosition(selectedPosition);
    VH targetViewHolder = (VH) parent.findViewHolderForAdapterPosition(targetPosition);
    if(selectedViewHolder == null || targetViewHolder == null) return;
    onStartMergeAnimation(selectedViewHolder, targetViewHolder, selectedPosition, targetPosition,duration);
}
 

@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
    super.onScrolled(recyclerView, dx, dy);
    if (recyclerView.getAdapter() == null) return;
    RecyclerView.ViewHolder viewHolder = recyclerView.findViewHolderForAdapterPosition(0);
    if (viewHolder != null && viewHolder.itemView != null) {
        int currentScroll = recyclerView.computeVerticalScrollOffset();
        setTranslationY(-currentScroll - getHeight());

        dispatchOverScroll(-currentScroll, recyclerView.getScrollState());
    }
}
 

/**
 * Calls through to the {@link ParentViewHolder} to collapse views for each
 * {@link RecyclerView} a specified parent is a child of. These calls to
 * the {@code ParentViewHolder} are made so that animations can be
 * triggered at the {@link android.support.v7.widget.RecyclerView.ViewHolder}
 * level.
 *
 * @param parentIndex The index of the parent to collapse
 */
private void collapseViews(ParentWrapper parentWrapper, int parentIndex) {
    for (RecyclerView recyclerView : mAttachedRecyclerViewPool) {
        RecyclerView.ViewHolder viewHolder = recyclerView.findViewHolderForAdapterPosition(parentIndex);
        if (viewHolder != null
                && ((ParentViewHolder) viewHolder).isExpanded()) {
            ((ParentViewHolder) viewHolder).setExpanded(false);
            ((ParentViewHolder) viewHolder).onExpansionToggled(true);
        }

        collapseHelperItem(parentWrapper, parentIndex, true);
    }
}
 

@SuppressWarnings("unchecked")
@Override
public void onMergeCancel(RecyclerView parent, int selectedPosition, int targetPosition) {
    VH selectedViewHolder = (VH) parent.findViewHolderForAdapterPosition(selectedPosition);
    VH targetViewHolder = (VH) parent.findViewHolderForAdapterPosition(targetPosition);
    if(selectedViewHolder == null || targetViewHolder == null) return;
     onMergeCancel(selectedViewHolder, targetViewHolder, selectedPosition, targetPosition);
}
 

@Nullable
public static View getItemView(@Nullable final RecyclerView recyclerView, final int position) {
    if (recyclerView != null) {
        final RecyclerView.ViewHolder vh = recyclerView
                .findViewHolderForAdapterPosition(position);
        if (vh != null) {
            return vh.itemView;
        }
    }
    return null;
}
 

private void computeOffsetWith(RecyclerView recyclerView) {
    if (recyclerView.getAdapter() == null) {
        setTranslationY(getMeasuredHeight());
        return;
    }
    int lastPosition = recyclerView.getAdapter().getItemCount() - 1;
    RecyclerView.ViewHolder viewHolder = recyclerView.findViewHolderForAdapterPosition(lastPosition);
    if (viewHolder != null && viewHolder.itemView != null && viewHolder.itemView.isShown()) {
        int scrollRange = recyclerView.computeVerticalScrollRange();
        int currentScroll = recyclerView.computeVerticalScrollOffset();
        int rHeight = recyclerView.getHeight();
        int rPadTop = recyclerView.getPaddingTop();
        int offset = scrollRange - currentScroll - rHeight + getHeight() + rPadTop;

        checkAutoLoad();
        setTranslationY(offset);
        if (offset < 0) {
            dispatchOverScroll(offset, recyclerView.getScrollState());
        }
    } else if (recyclerView.getAdapter().getItemCount() == 0) {//no item
        setTranslationY(-recyclerView.getHeight() / 2 + getMeasuredHeight() / 2);
        checkAutoLoad();

    } else {
        setTranslationY(getMeasuredHeight());
    }
}
 

/**
 * Calls through to the ParentViewHolder to expand views for each
 * RecyclerView the specified parent is a child of.
 * <p>
 * These calls to the ParentViewHolder are made so that animations can be
 * triggered at the ViewHolder level.
 *
 * @param flatParentPosition The index of the parent to expand
 */
@SuppressWarnings("unchecked")
@UiThread
private void expandViews(@NonNull ExpandableWrapper<P, C> parentWrapper, int flatParentPosition) {
    PVH viewHolder;
    for (RecyclerView recyclerView : mAttachedRecyclerViewPool) {
        viewHolder = (PVH) recyclerView.findViewHolderForAdapterPosition(flatParentPosition);
        if (viewHolder != null && !viewHolder.isExpanded()) {
            viewHolder.setExpanded(true);
            viewHolder.onExpansionToggled(false);
        }
    }

    updateExpandedParent(parentWrapper, flatParentPosition, false);
}
 

/**
 * 同步 attach 到当前 adapter 的所有 RecyclerView 指定的适配器位置的 parentItem 的展开状态
 * <p>
 * <b>注意:</b>可能由于 ParentItem 未 laid out 到 RecyclerView 并且 RecyclerView 没有正确回调
 * {@link #onBindParentViewHolder(ParentViewHolder, int)} 方法导致同步
 * 展开状态失败，这里存储待处理的 parentItem 的位置，以至于能够在 {@link #onViewAttachedToWindow(BaseViewHolder)}
 * 时处理状态同步逻辑
 * </p>
 *
 * @param parentPosition 指定的同步展开状态的 parent 的在父列表项里的位置
 */
@SuppressWarnings("unchecked")
private void syncViewExpansionState(Integer parentPosition, boolean byUser)
{
    Logger.e(TAG, "syncViewExpansionState=>" + parentPosition);
    int parentAdapterPos = getParentAdapterPosition(parentPosition);
    if (parentAdapterPos == RecyclerView.NO_POSITION) return;
    ItemWrapper itemWrapper = getItem(parentAdapterPos);
    boolean expanded = itemWrapper.isExpanded();

    for (RecyclerView rv : mAttachedRecyclerViews) {
        PVH pvh = (PVH) rv.findViewHolderForAdapterPosition(parentAdapterPos);
        if (pvh != null && !pvh.isExpanded() && expanded) {
            //这里需要额外判断当该 parent 可以 expandable 时才应用同步设置和通知展开逻辑
            //防止不可展开的 parent 的不必要的同步设置和通知处理
            pvh.setExpanded(true);
            notifyParentExpanded(pvh, false, byUser);
        } else if (pvh == null && expanded) {
            Logger.e(TAG, "expandViews pvh is null---->parentPos=" + parentPosition +
                          ",parentAdapterPos=" + parentAdapterPos);
            //未 laid out 的 Parent ,虽然无法获取并设置展开折叠标识，
            // 这里添加待处理展开逻辑的所有 parentItem 的 position
            // 如果先前已经记录待折叠位置记录，移除该记录并以最新的待展开记录为准!
            pendingCollapseRemove(rv, parentPosition);

            pendingExpandAdd(rv, parentPosition);
        }
    }
}
 

@SuppressWarnings("unchecked")
@Override
public void onItemClick(RecyclerView recyclerView, int position, View pressedView) {
    VH viewHolder = (VH) recyclerView.findViewHolderForAdapterPosition(position);
    if(viewHolder != null)
        PrimitiveSimpleAdapter.this.onItemClick(viewHolder,mParentPosition,position);
}
 

/**
 * Dismiss the swipe menu for the view at position
 * @param position the position of the item to dismiss
 */
public void dismissSwipeMenu(RecyclerView recyclerView, int position) {
    // retrieve the viewholder at position
    RecyclerView.ViewHolder viewHolder = recyclerView.findViewHolderForAdapterPosition(position);

    // check if the viewholder is an instance of ConversationListAdapter.ViewHolder
    if(viewHolder instanceof ViewHolder) {

        // cast the holder to ConversationListAdapter.ViewHolder
        ViewHolder holder = (ViewHolder) viewHolder;

        // dismiss the menu
        holder.swipeItem.close();
    }
}
 

private int getScrollDistanceOfColumnClosestToLeft(final RecyclerView recyclerView) {
    final LinearLayoutManager manager = (LinearLayoutManager) recyclerView.getLayoutManager();
    final RecyclerView.ViewHolder firstVisibleColumnViewHolder = recyclerView.findViewHolderForAdapterPosition(manager.findFirstVisibleItemPosition());
    if (firstVisibleColumnViewHolder == null) {
        return 0;
    }

    Log.d("YouQi", "firstVisibleColumnViewHolder: " + firstVisibleColumnViewHolder.getAdapterPosition());

    final int columnWidth = firstVisibleColumnViewHolder.itemView.getMeasuredWidth();
    final int left = firstVisibleColumnViewHolder.itemView.getLeft();
    final int absoluteLeft = Math.abs(left);

    final int columnHeight = firstVisibleColumnViewHolder.itemView.getMeasuredHeight();
    final int top = firstVisibleColumnViewHolder.itemView.getTop();
    final int absoluteTop = Math.abs(top);

    Log.d("YouQi", "columnWidth: " + columnWidth);
    Log.d("YouQi", "left: " + left);
    Log.d("YouQi", "absoluteLeft: " + absoluteLeft);

    Log.d("YouQi", "columnHeight: " + columnHeight);
    Log.d("YouQi", "top: " + top);
    Log.d("YouQi", "absoluteTop: " + absoluteTop);

    //return absoluteLeft <= (columnWidth / 2) ? left : columnWidth - absoluteLeft;
    return absoluteTop <= (columnHeight / 2) ? top : columnHeight - absoluteTop;
}
 

public Matcher<View> atPositionOnView(final int position, final int targetViewId) {
    return new TypeSafeMatcher<View>() {
        Resources resources;
        View childView;

        public void describeTo(Description description) {
            String idDescription = Integer.toString(recyclerViewId);
            if (this.resources != null) {
                try {
                    idDescription = this.resources.getResourceName(recyclerViewId);
                } catch (Resources.NotFoundException var4) {
                    idDescription = String.format("%s (resource name not found)",
                            recyclerViewId);
                }
            }
            description.appendText("RecyclerView with id: "
                    + idDescription
                    + " at position: "
                    + position);
        }

        public boolean matchesSafely(View view) {

            this.resources = view.getResources();

            if (childView == null) {
                RecyclerView recyclerView =
                        (RecyclerView) view.getRootView().findViewById(recyclerViewId);
                if (recyclerView != null && recyclerView.getId() == recyclerViewId) {
                    RecyclerView.ViewHolder viewHolder = recyclerView.
                            findViewHolderForAdapterPosition(position);
                    if (viewHolder != null) {
                        childView = viewHolder.itemView;
                    }
                } else {
                    return false;
                }
            }

            if (targetViewId == -1) {
                return view.equals(childView);
            } else {
                View targetView = childView.findViewById(targetViewId);
                return view.equals(targetView);
            }
        }
    };
}
 

public Matcher<View> atPositionOnView(final int position, final int targetViewId) {

        return new TypeSafeMatcher<View>() {
            Resources resources = null;
            View childView;

            public void describeTo(Description description) {
                String idDescription = Integer.toString(recyclerViewId);
                if (this.resources != null) {
                    try {
                        idDescription = this.resources.getResourceName(recyclerViewId);
                    } catch (Resources.NotFoundException var4) {
                        idDescription = String.format("%s (resource name not found)",
                                new Object[]{Integer.valueOf
                                        (recyclerViewId)});
                    }
                }

                description.appendText("with id: " + idDescription);
            }

            public boolean matchesSafely(View view) {

                this.resources = view.getResources();

                if (childView == null) {
                    RecyclerView recyclerView =
                            (RecyclerView) view.getRootView().findViewById(recyclerViewId);
                    if (recyclerView != null && recyclerView.getId() == recyclerViewId) {
                        childView = recyclerView.findViewHolderForAdapterPosition(position).itemView;
                    } else {
                        return false;
                    }
                }

                if (targetViewId == -1) {
                    return view == childView;
                } else {
                    View targetView = childView.findViewById(targetViewId);
                    return view == targetView;
                }

            }
        };
    }
 

public Matcher<View> atPositionOnView(final int position, final int targetViewId) {

        return new TypeSafeMatcher<View>() {
            Resources resources = null;
            View childView;

            public void describeTo(Description description) {
                String idDescription = Integer.toString(recyclerViewId);
                if (this.resources != null) {
                    try {
                        idDescription = this.resources.getResourceName(recyclerViewId);
                    } catch (Resources.NotFoundException var4) {
                        idDescription = String.format("%s (resource name not found)",
                                                      new Object[] { Integer.valueOf
                                                          (recyclerViewId) });
                    }
                }

                description.appendText("with id: " + idDescription);
            }

            public boolean matchesSafely(View view) {

                this.resources = view.getResources();

                if (childView == null) {
                    RecyclerView recyclerView =
                        (RecyclerView) view.getRootView().findViewById(recyclerViewId);
                    if (recyclerView != null && recyclerView.getId() == recyclerViewId) {
                        childView = recyclerView.findViewHolderForAdapterPosition(position).itemView;
                    }
                    else {
                        return false;
                    }
                }

                if (targetViewId == -1) {
                    return view == childView;
                } else {
                    View targetView = childView.findViewById(targetViewId);
                    return view == targetView;
                }

            }
        };
    }
 

/**
 * 绘制悬浮组
 *
 * @param c      Canvas
 * @param parent RecyclerView
 */
protected void onDrawOverGroup(Canvas c, RecyclerView parent) {
    int firstVisiblePosition = ((LinearLayoutManager) parent.getLayoutManager()).findFirstVisibleItemPosition();
    if (firstVisiblePosition == RecyclerView.NO_POSITION) {
        return;
    }
    Group group = getCroup(firstVisiblePosition);
    if (group == null)
        return;
    String groupTitle = group.toString();
    if (TextUtils.isEmpty(groupTitle)) {
        return;
    }
    boolean isRestore = false;
    Group nextGroup = getCroup(firstVisiblePosition + 1);
    if (nextGroup != null && !group.equals(nextGroup)) {
        //说明是当前组最后一个元素，但不一定碰撞了
        View child = parent.findViewHolderForAdapterPosition(firstVisiblePosition).itemView;
        if (child.getTop() + child.getMeasuredHeight() < mGroupHeight) {
            //进一步检测碰撞
            c.save();//保存画布当前的状态
            isRestore = true;
            c.translate(0, child.getTop() + child.getMeasuredHeight() - mGroupHeight);
        }
    }
    int left = parent.getPaddingLeft();
    int right = parent.getWidth() - parent.getPaddingRight();
    int top = parent.getPaddingTop();
    int bottom = top + mGroupHeight;
    c.drawRect(left, top, right, bottom, mBackgroundPaint);
    float x;
    float y = top + mTextBaseLine;
    if (isCenter) {
        x = parent.getMeasuredWidth() / 2 - getTextX(groupTitle);
    } else {
        x = mPaddingLeft;
    }
    c.drawText(groupTitle, x, y, mTextPaint);
    if (isRestore) {
        //还原画布为初始状态
        c.restore();
    }
}