Java GridLayoutManager.findLastVisibleItemPosition方法代码示例

import android.support.v7.widget.GridLayoutManager; //导入方法依赖的package包/类
public void refreshSelection() {
    GridLayoutManager layoutManager = (GridLayoutManager) mRecyclerView.getLayoutManager();
    int first = layoutManager.findFirstVisibleItemPosition();
    int last = layoutManager.findLastVisibleItemPosition();
    if (first == -1 || last == -1) {
        return;
    }
    Cursor cursor = getCursor();
    for (int i = first; i <= last; i++) {
        RecyclerView.ViewHolder holder = mRecyclerView.findViewHolderForAdapterPosition(first);
        if (holder instanceof MediaViewHolder) {
            if (cursor.moveToPosition(i)) {
                setCheckStatus(Item.valueOf(cursor), ((MediaViewHolder) holder).mMediaGrid);
            }
        }
    }
}
 

import android.support.v7.widget.GridLayoutManager; //导入方法依赖的package包/类
private static int getLastVisibleItemPosition() {
    Class recyclerViewLMClass = recyclerView.getLayoutManager().getClass();
    if (recyclerViewLMClass == LinearLayoutManager.class) {
        LinearLayoutManager linearLayoutManager = (LinearLayoutManager) recyclerView.getLayoutManager();
        return linearLayoutManager.findLastVisibleItemPosition();
    } else if (recyclerViewLMClass == GridLayoutManager.class) {
        GridLayoutManager gridLayoutManager = (GridLayoutManager) recyclerView.getLayoutManager();
        return gridLayoutManager.findLastVisibleItemPosition();
    } else if (recyclerViewLMClass == StaggeredGridLayoutManager.class || StaggeredGridLayoutManager.class.isAssignableFrom(recyclerViewLMClass)) {
        StaggeredGridLayoutManager staggeredGridLayoutManager = (StaggeredGridLayoutManager) recyclerView.getLayoutManager();
        int[] into = staggeredGridLayoutManager.findLastVisibleItemPositions(null);
        List<Integer> intoList = new ArrayList<>();
        for (int i : into) {
            intoList.add(i);
        }
        return Collections.max(intoList);
    }
    throw new RuntimeException("Unknown LayoutManager class: " + recyclerViewLMClass.toString());
}
 

import android.support.v7.widget.GridLayoutManager; //导入方法依赖的package包/类
public void refreshSelection() {
    GridLayoutManager layoutManager = (GridLayoutManager) mRecyclerView.getLayoutManager();
    int first = layoutManager.findFirstVisibleItemPosition();
    int last = layoutManager.findLastVisibleItemPosition();
    if (first == -1 || last == -1) {
        return;
    }
    Cursor cursor = getCursor();
    for (int i = first; i <= last; i++) {
        RecyclerView.ViewHolder holder = mRecyclerView.findViewHolderForAdapterPosition(first);
        if (holder instanceof MediaViewHolder) {
            if (cursor.moveToPosition(i)) {
                setCheckStatus(MediaInfo.valueOf(cursor), ((MediaViewHolder) holder).mMediaGrid);
            }
        }
    }
}
 

import android.support.v7.widget.GridLayoutManager; //导入方法依赖的package包/类
@Override
public void onScrollStateChanged(int state) {
    super.onScrollStateChanged(state);
    switch (state) {
        case SCROLL_STATE_IDLE:
            LayoutManager layoutManager = getLayoutManager();
            int itemCount = getAdapter().getItemCount();
            int lastVisibleItemPosition = 0;

            if (layoutManager instanceof GridLayoutManager) {
                GridLayoutManager gridLayoutManager = (GridLayoutManager) layoutManager;
                lastVisibleItemPosition = gridLayoutManager.findLastVisibleItemPosition();
            } else if (layoutManager instanceof LinearLayoutManager) {
                LinearLayoutManager linearLayoutManager = (LinearLayoutManager) layoutManager;
                lastVisibleItemPosition = linearLayoutManager.findLastVisibleItemPosition();
            }

            if (lastVisibleItemPosition >= itemCount - 1) {
                if (getParent() instanceof SwipeRefreshLayout) {
                    SwipeRefreshLayout swipeRefreshLayout = (SwipeRefreshLayout) getParent();
                    if (swipeRefreshLayout.isRefreshing()) {
                        break;
                    }
                }

                if (mOnLoadMoreListener != null && mScrollDy > 0) {
                    if (!mIsLoadingMore) {
                        synchronized (EnhanceRecyclerView.class) {
                            if (!mIsLoadingMore) {
                                mIsLoadingMore = true;
                                mInternalAdapter.setFootViewVisible(true);
                                mOnLoadMoreListener.onLoadMore();
                            }
                        }
                    }
                }
            }
            break;
    }
}
 

import android.support.v7.widget.GridLayoutManager; //导入方法依赖的package包/类
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
    if (dy < 0 || loadMoreSubject == null || loadMoreSubject.isLoading()){
        return;
    }

    int lastItem = 0;
    RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
    int totalItemCount = layoutManager.getItemCount();
    if (layoutManager instanceof GridLayoutManager) {
        GridLayoutManager gridLayoutManager = ((GridLayoutManager) layoutManager);
        //Position to find the final item of the current LayoutManager
        lastItem = gridLayoutManager.findLastCompletelyVisibleItemPosition();
        if (lastItem == -1){
            lastItem = gridLayoutManager.findLastVisibleItemPosition();
        }
    } else if (layoutManager instanceof LinearLayoutManager) {
        LinearLayoutManager linearLayoutManager = ((LinearLayoutManager) layoutManager);
        lastItem = linearLayoutManager.findLastCompletelyVisibleItemPosition();
        if (lastItem == -1){
            lastItem = linearLayoutManager.findLastVisibleItemPosition();
        }
    } else if (layoutManager instanceof StaggeredGridLayoutManager) {
        StaggeredGridLayoutManager staggeredGridLayoutManager = ((StaggeredGridLayoutManager) layoutManager);
        // since may lead to the final item has more than one StaggeredGridLayoutManager the particularity of the so here that is an array
        // this array into an array of position and then take the maximum value that is the last show the position value
        int[] lastPositions = staggeredGridLayoutManager.findLastCompletelyVisibleItemPositions(null);
        lastItem = findMax(lastPositions);
    }
    final int childCount = layoutManager.getChildCount();
    final boolean shouldLoadMore = (childCount > 0 && lastItem >= totalItemCount - VISIBLE_THRESHOLD);
    if (shouldLoadMore) {
        loadMoreSubject.onLoadMore();
    }
}
 

import android.support.v7.widget.GridLayoutManager; //导入方法依赖的package包/类
private void doClickOtherToNavigation(ViewGroup parent, int position, MyViewHolder myHolder) {
    RecyclerView recyclerView = (RecyclerView) parent;
    LayoutManager manager = recyclerView.getLayoutManager();
    View currentView = manager.findViewByPosition(myHolder.getAdapterPosition());
    View preTargetView = manager.findViewByPosition(this.mTopSize);
    GridLayoutManager gridLayoutManager = (GridLayoutManager) manager;
    int spanCount = gridLayoutManager.getSpanCount();
    int targetPosition = this.mTopSize + 1;
    if (recyclerView.indexOfChild(preTargetView) >= 0) {
        int targetX = preTargetView.getLeft();
        int targetY = preTargetView.getTop();
        if ((targetPosition - 1) % spanCount == 0) {
            View targetView = manager.findViewByPosition(targetPosition);
            targetX = targetView.getLeft();
            targetY = targetView.getTop();
        } else {
            targetX += preTargetView.getWidth() + UIsUtils.dipToPx(TitleBar.SHAREBTN_RIGHT_MARGIN);
            if (gridLayoutManager.findLastVisibleItemPosition() == getItemCount() - 1 && (((getItemCount() - 1) - this.mTopSize) - 2) % spanCount == 0) {
                if (gridLayoutManager.findFirstVisibleItemPosition() != 0) {
                    targetY += preTargetView.getHeight() + UIsUtils.dipToPx(TitleBar.SHAREBTN_RIGHT_MARGIN);
                } else if (gridLayoutManager.findFirstCompletelyVisibleItemPosition() != 0) {
                    targetY += (-recyclerView.getChildAt(0).getTop()) - recyclerView.getPaddingTop();
                }
            }
        }
        moveOtherToMy(myHolder);
        startAnimation(recyclerView, currentView, (float) targetX, (float) targetY);
        return;
    }
    moveOtherToMy(myHolder);
    int index = (this.mTopSize % spanCount) - 1;
    if (index < 0) {
        index = spanCount - 1;
    }
    startAnimation(recyclerView, currentView, (float) ((currentView.getWidth() * index) + (index == 0 ? 0 : (index - 1) * UIsUtils.dipToPx(TitleBar.SHAREBTN_RIGHT_MARGIN))), 0.0f);
}
 

import android.support.v7.widget.GridLayoutManager; //导入方法依赖的package包/类
/**
 * Checks if the user started this activity by pressing the back button on another main activity.
 * If so it runs the show animation for the activity's icon, text and visual elements.
 */
public void checkIsBackFromMainActivity() {
	if(isTransitioned) {
		GridLayoutManager manager = (GridLayoutManager) mRecyclerView.getLayoutManager();
		final int DELAY_BETWEEN = 50;
		int firstVisibleItemPosition = manager.findFirstVisibleItemPosition();
		int lastVisibleItemPosition = manager.findLastVisibleItemPosition();

		int startPositionCol = AnimationService.getColumnPosFromIndex(firstVisibleItemPosition, mRecyclerView);
		int startPositionRow = AnimationService.getRowPosFromIndex(firstVisibleItemPosition, mRecyclerView);

		// Show the Activity Icon and Text
		AnimationService.startAlphaRevealAnimation(mCircleIconWrapper);
		AnimationService.startAlphaRevealAnimation(mTitleView);

		// Fake fill the RecyclerViews with children again
		for(int i = firstVisibleItemPosition; i <= lastVisibleItemPosition; i++) {
			final View mView = mRecyclerView.getChildAt(i-firstVisibleItemPosition);

			int positionColumnDistance = Math.abs(AnimationService.getColumnPosFromIndex(i, mRecyclerView) - startPositionCol);
			int positionRowDistance = Math.abs(AnimationService.getRowPosFromIndex(i, mRecyclerView) - startPositionRow);
			int delay = (positionColumnDistance + positionRowDistance) * DELAY_BETWEEN;

			//int delay = (i - firstVisibleItemPosition) * DELAY_BETWEEN;
			if(mView != null) {
				AnimationService.startAlphaRevealAnimation(delay, mView, mAdapter instanceof StreamsAdapter);
			}
		}
		isTransitioned = false;
	}
}
 

import android.support.v7.widget.GridLayoutManager; //导入方法依赖的package包/类
public void checkForNewElements(RecyclerView recyclerView) {
	int currentOffset = mLazyFetchingActivity.getCurrentOffset();
	int maxElementsToFetchTotal = mLazyFetchingActivity.getMaxElementsToFetch();

	// If the task has already been run, make a new task as a task can only be run once.
	if(getElementsTask.getStatus() == AsyncTask.Status.FINISHED) {
		getElementsTask = new GetVisualElementsTask<>();
	}

	// Only bother to check if we need to fetch more game objects if we are not already in the process of doing so.
	if(getElementsTask.getStatus() != AsyncTask.Status.RUNNING && currentOffset < maxElementsToFetchTotal) {
		GridLayoutManager lm = (GridLayoutManager) recyclerView.getLayoutManager();
		RecyclerView.Adapter mAdapter = recyclerView.getAdapter();
		if (mAdapter == null ){
			return;
		}

		int lastViewPosition = lm.findLastVisibleItemPosition();
		int spanCount = lm.getSpanCount();
		int itemCount = mAdapter.getItemCount();
		final double FETCH_WHEN_BELOW_FIVE = 5;
		final double NUMBER_OF_ROWS = Math.ceil(itemCount / (spanCount * 1.0)); // Round UP to the nearest Integer
		final double LAST_ROW_VISIBLE = Math.ceil(lastViewPosition/(spanCount * 1.0)); // Round UP to the nearest Integer

		// If the Second to last or the last row is visible, then fetch more game objects.
		if(LAST_ROW_VISIBLE >= NUMBER_OF_ROWS - FETCH_WHEN_BELOW_FIVE) {
			getElementsTask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, mLazyFetchingActivity);
			mLazyFetchingActivity.startProgress();
		}
	}
}
 

import android.support.v7.widget.GridLayoutManager; //导入方法依赖的package包/类
private void scroll_load_more_detection(RecyclerView recyclerView) {

        RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();

        if (layoutManagerType == null) {
            if (layoutManager instanceof GridLayoutManager) {
                layoutManagerType = LAYOUT_MANAGER_TYPE.GRID;
            } else if (layoutManager instanceof StaggeredGridLayoutManager) {
                layoutManagerType = LAYOUT_MANAGER_TYPE.STAGGERED_GRID;
            } else if (layoutManager instanceof LinearLayoutManager) {
                layoutManagerType = LAYOUT_MANAGER_TYPE.LINEAR;
            } else {
                throw new RuntimeException("Unsupported LayoutManager used. Valid ones are LinearLayoutManager, GridLayoutManager and StaggeredGridLayoutManager");
            }
        }

        mTotalItemCount = layoutManager.getItemCount();
        mVisibleItemCount = layoutManager.getChildCount();

        switch (layoutManagerType) {
            case LINEAR:
                mFirstVisibleItem = mRecyclerViewHelper.findFirstVisibleItemPosition();
                lastVisibleItemPosition = mRecyclerViewHelper.findLastVisibleItemPosition();
                break;
            case GRID:
                if (layoutManager instanceof GridLayoutManager) {
                    GridLayoutManager ly = (GridLayoutManager) layoutManager;
                    lastVisibleItemPosition = ly.findLastVisibleItemPosition();
                    mFirstVisibleItem = ly.findFirstVisibleItemPosition();
                }
                break;
            case STAGGERED_GRID:
                if (layoutManager instanceof StaggeredGridLayoutManager) {
                    StaggeredGridLayoutManager sy = (StaggeredGridLayoutManager) layoutManager;

                    if (mlastPositionsStaggeredGridLayout == null)
                        mlastPositionsStaggeredGridLayout = new int[sy.getSpanCount()];

                    sy.findLastVisibleItemPositions(mlastPositionsStaggeredGridLayout);
                    lastVisibleItemPosition = findMax(mlastPositionsStaggeredGridLayout);

                    sy.findFirstVisibleItemPositions(mlastPositionsStaggeredGridLayout);
                    mFirstVisibleItem = findMin(mlastPositionsStaggeredGridLayout);
                }
                break;
        }

        if (automaticLoadMoreEnabled) {

            if (mTotalItemCount > previousTotal) {
                automaticLoadMoreEnabled = false;
                previousTotal = mTotalItemCount;
            }
        }

        boolean bottomEdgeHit = (mTotalItemCount - mVisibleItemCount) <= mFirstVisibleItem;

        if (bottomEdgeHit) {
            if (mIsLoadMoreWidgetEnabled) {
                /**auto activate load more**/
                if (!automaticLoadMoreEnabled) {
                    onLoadMoreListener.loadMore(mRecyclerView.getAdapter().getItemCount(), lastVisibleItemPosition);
                    automaticLoadMoreEnabled = true;
                }
            }
            mAdapter.internalExecuteLoadingView();
            previousTotal = mTotalItemCount;
        }
    }
 

import android.support.v7.widget.GridLayoutManager; //导入方法依赖的package包/类
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
    super.onScrolled(recyclerView, dx, dy);
    int lastItem = 0;
    int firstItem = 0;
    RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
    int totalItemCount = layoutManager.getItemCount();
    if (layoutManager instanceof GridLayoutManager) {
        GridLayoutManager gridLayoutManager = ((GridLayoutManager) layoutManager);
        firstItem = gridLayoutManager.findFirstCompletelyVisibleItemPosition();
        //Position to find the final item of the current LayoutManager
        lastItem = gridLayoutManager.findLastCompletelyVisibleItemPosition();
        if (lastItem == -1) lastItem = gridLayoutManager.findLastVisibleItemPosition();
    } else if (layoutManager instanceof LinearLayoutManager) {
        LinearLayoutManager linearLayoutManager = ((LinearLayoutManager) layoutManager);
        firstItem = linearLayoutManager.findFirstCompletelyVisibleItemPosition();
        lastItem = linearLayoutManager.findLastCompletelyVisibleItemPosition();
        if (lastItem == -1) lastItem = linearLayoutManager.findLastVisibleItemPosition();
    } else if (layoutManager instanceof StaggeredGridLayoutManager) {
        StaggeredGridLayoutManager staggeredGridLayoutManager = ((StaggeredGridLayoutManager) layoutManager);
        // since may lead to the final item has more than one StaggeredGridLayoutManager the particularity of the so here that is an array
        // this array into an array of position and then take the maximum value that is the last show the position value
        int[] lastPositions = new int[((StaggeredGridLayoutManager) layoutManager).getSpanCount()];
        staggeredGridLayoutManager.findLastCompletelyVisibleItemPositions(lastPositions);
        lastItem = findMax(lastPositions);
        firstItem = staggeredGridLayoutManager.findFirstVisibleItemPositions(lastPositions)[0];
    }
    if (firstItem == 0 || firstItem == RecyclerView.NO_POSITION) {
        if (mPullLoadMoreRecyclerView.getPullRefreshEnable())
            mPullLoadMoreRecyclerView.setSwipeRefreshEnable(true);
    } else {
        mPullLoadMoreRecyclerView.setSwipeRefreshEnable(false);
    }
    if (mPullLoadMoreRecyclerView.getPushRefreshEnable()
            && !mPullLoadMoreRecyclerView.isRefresh()
            && mPullLoadMoreRecyclerView.isHasMore()
            && (lastItem == totalItemCount - 1)
            && !mPullLoadMoreRecyclerView.isLoadMore()
            && (dx > 0 || dy > 0)) {
        mPullLoadMoreRecyclerView.setIsLoadMore(true);
        mPullLoadMoreRecyclerView.loadMore();
    }

}
 

import android.support.v7.widget.GridLayoutManager; //导入方法依赖的package包/类
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
  super.onScrolled(recyclerView, dx, dy);
  RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
  if(listener == null){
    return;
  }
  IOnLoadMoreListener iOnLoadMoreListener = listener.get();

  if(iOnLoadMoreListener!=null) {

    iOnLoadMoreListener.onBeforeScroll(dx, dy);

    if (layoutManager instanceof LinearLayoutManager) {
      layoutManagerType = LAYOUT_MANAGER_TYPE.LINEAR;
      LinearLayoutManager linearLayoutManager = (LinearLayoutManager) layoutManager;
      mLastVisibleItemPosition = linearLayoutManager.findLastVisibleItemPosition();
      int firstVisible = linearLayoutManager.findFirstVisibleItemPosition();
      iOnLoadMoreListener.notifyAppearStateChange(firstVisible
          , mLastVisibleItemPosition
          , dx
          , dy);
    } else if (layoutManager instanceof GridLayoutManager) {
      layoutManagerType = LAYOUT_MANAGER_TYPE.GRID;
      GridLayoutManager gridLayoutManager = (GridLayoutManager) layoutManager;
      mLastVisibleItemPosition = gridLayoutManager.findLastVisibleItemPosition();
      iOnLoadMoreListener.notifyAppearStateChange(gridLayoutManager.findFirstVisibleItemPosition()
          , mLastVisibleItemPosition
          , dx
          , dy);

    } else if (layoutManager instanceof StaggeredGridLayoutManager) {
      layoutManagerType = LAYOUT_MANAGER_TYPE.STAGGERED_GRID;
      StaggeredGridLayoutManager staggeredGridLayoutManager = (StaggeredGridLayoutManager) layoutManager;
      int newSpanCount = staggeredGridLayoutManager.getSpanCount();
      if (mLastPositions == null || newSpanCount != mLastPositions.length) {
        mLastPositions = new int[newSpanCount];
      }
      if (mFirstPositions == null || newSpanCount != mFirstPositions.length) {
        mFirstPositions = new int[newSpanCount];
      }
      //avoid crash of support-v7 original bug
      try{
        staggeredGridLayoutManager.findFirstVisibleItemPositions(mFirstPositions);
        mFirstVisibleItemPosition = findMin(mFirstPositions);
        staggeredGridLayoutManager.findLastVisibleItemPositions(mLastPositions);
        mLastVisibleItemPosition = findMax(mLastPositions);
        iOnLoadMoreListener.notifyAppearStateChange(
            mFirstVisibleItemPosition
            , mLastVisibleItemPosition
            , dx
            , dy);

      }catch(Exception e){
        e.printStackTrace();
        WXLogUtils.e(e.toString());
      }

    } else {
      throw new RuntimeException(
          "Unsupported LayoutManager used. Valid ones are LinearLayoutManager, GridLayoutManager and StaggeredGridLayoutManager");
    }
  }
}