android.support.v7.widget.StaggeredGridLayoutManager#findFirstVisibleItemPositions ( )源码实例Demo

下面列出了android.support.v7.widget.StaggeredGridLayoutManager#findFirstVisibleItemPositions ( ) 实例代码，或者点击链接到github查看源代码，也可以在右侧发表评论。

源代码1 项目： AndroidDemo 文件： ScrollableViewCompat.java

@Override
public boolean viewCanScrollUp() {
    if (view == null)
        return false;
    RecyclerView.LayoutManager manager = view.getLayoutManager();
    if (manager == null)
        return false;
    if (manager instanceof LinearLayoutManager) {
        LinearLayoutManager lm = (LinearLayoutManager) manager;
        if (lm.getOrientation() == LinearLayoutManager.HORIZONTAL) {
            return false;
        }
        return lm.findFirstVisibleItemPosition() > 0 || lm.findViewByPosition(0).getTop() < view.getPaddingTop();
    } else if (manager instanceof StaggeredGridLayoutManager) {
        StaggeredGridLayoutManager g = (StaggeredGridLayoutManager) manager;
        int[] info = g.findFirstVisibleItemPositions(null);
        return info[0] > 0;
    }
    return false;
}

源代码2 项目： TigerVideo 文件： CommonRecyclerView.java

/**
 * 获取第一个显示的位置
 *
 * @return
 */
public int getFirstVisiblePosition() {

    int position;
    if (getLayoutManager() instanceof LinearLayoutManager) {
        position = ((LinearLayoutManager) getLayoutManager()).findFirstVisibleItemPosition();
    } else if (getLayoutManager() instanceof GridLayoutManager) {
        position = ((GridLayoutManager) getLayoutManager()).findFirstVisibleItemPosition();
    } else if (getLayoutManager() instanceof StaggeredGridLayoutManager) {
        StaggeredGridLayoutManager layoutManager = (StaggeredGridLayoutManager) getLayoutManager();
        int[] lastPositions = layoutManager.findFirstVisibleItemPositions(new int[layoutManager.getSpanCount()]);
        position = getMinPosition(lastPositions);
    } else {
        position = 0;
    }
    return position;
}

源代码3 项目： nono-android 文件： RecycleViewHelper.java

public static int getRecycleViewFirstViewPosition(RecyclerView recyclerView){
    int position;
    if (recyclerView.getLayoutManager() instanceof LinearLayoutManager) {
        position = ((LinearLayoutManager) recyclerView.getLayoutManager()).findFirstVisibleItemPosition();
    } else if (recyclerView.getLayoutManager() instanceof GridLayoutManager) {
        position = ((GridLayoutManager) recyclerView.getLayoutManager()).findFirstVisibleItemPosition();
    } else if (recyclerView.getLayoutManager() instanceof StaggeredGridLayoutManager) {
        StaggeredGridLayoutManager layoutManager = (StaggeredGridLayoutManager) recyclerView.getLayoutManager();
        int[] lastPositions = layoutManager.findFirstVisibleItemPositions(new int[layoutManager.getSpanCount()]);
        int size = lastPositions.length;
        int minPosition = Integer.MAX_VALUE;
        for (int i = 0; i < size; i++) {
            minPosition = Math.min(minPosition, lastPositions[i]);
        }
        position = minPosition;
    } else {
        //position =recyclerView. getLayoutManager().getItemCount() - 1;
        position = 0;
    }
    return position;
}

源代码4 项目： LoadMoreRecyclerView 文件： LoadMoreRecyclerView.java

/**
 * 获取第一条展示的位置
 *
 * @return
 */
private int getFirstVisiblePosition() {
    int position;
    if (getLayoutManager() instanceof LinearLayoutManager) {
        position = ((LinearLayoutManager) getLayoutManager()).findFirstVisibleItemPosition();
    } else if (getLayoutManager() instanceof GridLayoutManager) {
        position = ((GridLayoutManager) getLayoutManager()).findFirstVisibleItemPosition();
    } else if (getLayoutManager() instanceof StaggeredGridLayoutManager) {
        StaggeredGridLayoutManager layoutManager = (StaggeredGridLayoutManager) getLayoutManager();
        int[] lastPositions = layoutManager.findFirstVisibleItemPositions(new int[layoutManager.getSpanCount()]);
        position = getMinPositions(lastPositions);
    } else {
        position = 0;
    }
    return position;
}

源代码5 项目： monthweekmaterialcalendarview 文件： MonthWeekMaterialCalendarView.java

/**
 * 判断线性布局的recyclerView是否到达顶部
 *
 * @param view
 */
private boolean isAtTop(View view) {
    boolean isTop = false;
    if (view instanceof RecyclerView) {
        if (((RecyclerView) view).getLayoutManager() instanceof ILayoutManager) {
            if (((RecyclerView) view).getLayoutManager() instanceof LinearLayoutManager) {
                LinearLayoutManager linearLayoutManager = (LinearLayoutManager) ((RecyclerView) view).getLayoutManager();
                if (linearLayoutManager.findFirstCompletelyVisibleItemPosition() == 0) {
                    isTop = true;
                }
            }
            if (((RecyclerView) view).getLayoutManager() instanceof GridLayoutManager) {
                GridLayoutManager gridLayoutManager = (GridLayoutManager) ((RecyclerView) view).getLayoutManager();
                if (gridLayoutManager.findFirstCompletelyVisibleItemPosition() == 0) {
                    isTop = true;
                }
            }
            if (((RecyclerView) view).getLayoutManager() instanceof StaggeredGridLayoutManager) {
                StaggeredGridLayoutManager staggeredGridLayoutManager = (StaggeredGridLayoutManager) ((RecyclerView) view).getLayoutManager();
                int[] positions = new int[staggeredGridLayoutManager.getSpanCount()];
                staggeredGridLayoutManager.findFirstVisibleItemPositions(positions);
                if (findMin(positions) == 0) {
                    isTop = true;
                }
            }
        } else {
            throw new IllegalArgumentException("RecyclerView layoutManager must implement ILayoutManager");
        }

    }
    return isTop;
}

源代码6 项目： Melophile 文件： OnReachBottomListener.java

private int fetchFirstVisibleItemPosition() {
  if (layoutManager instanceof LinearLayoutManager) {
    return LinearLayoutManager.class.cast(layoutManager).findFirstVisibleItemPosition();
  } else if (layoutManager instanceof StaggeredGridLayoutManager) {
    StaggeredGridLayoutManager manager = StaggeredGridLayoutManager.class.cast(layoutManager);
    int[] result = manager.findFirstVisibleItemPositions(null);
    if (result != null && result.length > 0) {
      return result[0];
    }
  }
  return -1;
}

源代码7 项目： ht-refreshrecyclerview 文件： Utils.java

/**
 * 获取第一个可见/完全可见item的位置索引
 * @param layoutManager       RecyclerView.LayoutManager对象
 * @param isCompletelyVisible 是否完全可见
 * @return item的索引
 */
public static int getFirstItemPosition(@NonNull RecyclerView.LayoutManager layoutManager, boolean isCompletelyVisible) {
    int firstVisibleItemPosition = -1;
    if (layoutManager instanceof LinearLayoutManager) { //GridLayoutManager继承LinearLayoutManager
        LinearLayoutManager linearLayoutManager = (LinearLayoutManager) layoutManager;
        firstVisibleItemPosition = isCompletelyVisible ? linearLayoutManager.findFirstCompletelyVisibleItemPosition() : linearLayoutManager.findFirstVisibleItemPosition();
    } else if (layoutManager instanceof StaggeredGridLayoutManager) {
        StaggeredGridLayoutManager staggeredGridLayoutManager = (StaggeredGridLayoutManager) layoutManager;
        int[] firstVisibleItemPositions = isCompletelyVisible ? staggeredGridLayoutManager.findFirstCompletelyVisibleItemPositions(null) : staggeredGridLayoutManager.findFirstVisibleItemPositions(null);
        if (firstVisibleItemPositions != null && firstVisibleItemPositions.length > 0)
            firstVisibleItemPosition = firstVisibleItemPositions[0];
    }
    return firstVisibleItemPosition;
}

源代码8 项目： RecyclerViewManager 文件： LoadMoreRecyclerListener.java

@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
    super.onScrolled(recyclerView, dx, dy);

    hasCompleted = false;
    
    isLoadingMoreEnabled = dy > 0;

    RecyclerView.LayoutManager mLayoutManager = recyclerView.getLayoutManager();

    //初始化firstVisibleItemPosition和lastVisibleItemPosition
    if (null != mLayoutManager) {
        if (mLayoutManager instanceof LinearLayoutManager) {
            firstVisibleItemPosition = ((LinearLayoutManager) mLayoutManager)
                    .findFirstVisibleItemPosition();
            lastVisibleItemPosition = ((LinearLayoutManager) mLayoutManager)
                    .findLastVisibleItemPosition();
        } else if (mLayoutManager instanceof GridLayoutManager) {
            firstVisibleItemPosition = ((GridLayoutManager) mLayoutManager)
                    .findFirstVisibleItemPosition();
            lastVisibleItemPosition = ((GridLayoutManager) mLayoutManager)
                    .findLastVisibleItemPosition();
        } else if (mLayoutManager instanceof StaggeredGridLayoutManager) {
            StaggeredGridLayoutManager mStaggeredGridLayoutManager =
                    (StaggeredGridLayoutManager) mLayoutManager;
            if (null == mPositions) {
                mPositions = new int[mStaggeredGridLayoutManager.getSpanCount()];
            }
            mStaggeredGridLayoutManager.findFirstVisibleItemPositions(mPositions);
            mStaggeredGridLayoutManager.findLastVisibleItemPositions(mPositions);
            firstVisibleItemPosition = getFirst(mPositions);
            lastVisibleItemPosition = getLast(mPositions);
        } else {
            throw new IllegalArgumentException(
                    "The layoutManager must be one of LinearLayoutManager, " +
                            "GridLayoutManager or StaggeredGridLayoutManager");
        }
    }
}

源代码9 项目： YCAudioPlayer 文件： VerticalRecyclerView.java

@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
    LayoutManager layoutManager = getLayoutManager();
    if (layoutManager != null) {
        if (layoutManager instanceof GridLayoutManager) {
            lastVisibleItemPosition = ((GridLayoutManager) layoutManager).findLastVisibleItemPosition();
            firstVisibleItemPosition = ((GridLayoutManager) layoutManager).findFirstVisibleItemPosition();
        } else if (layoutManager instanceof LinearLayoutManager) {
            lastVisibleItemPosition = ((LinearLayoutManager) layoutManager).findLastVisibleItemPosition();
            firstVisibleItemPosition = ((LinearLayoutManager) layoutManager).findFirstVisibleItemPosition();
        } else if (layoutManager instanceof StaggeredGridLayoutManager) {
            StaggeredGridLayoutManager staggeredGridLayoutManager = (StaggeredGridLayoutManager) layoutManager;
            if (lastPositions == null) {
                lastPositions = new int[staggeredGridLayoutManager.getSpanCount()];
                firstPositions = new int[staggeredGridLayoutManager.getSpanCount()];
            }
            staggeredGridLayoutManager.findLastVisibleItemPositions(lastPositions);
            staggeredGridLayoutManager.findFirstVisibleItemPositions(firstPositions);
            lastVisibleItemPosition = findMax(lastPositions);
            firstVisibleItemPosition = findMin(firstPositions);
        }
    } else {
        throw new RuntimeException("Unsupported LayoutManager used. Valid ones are LinearLayoutManager, GridLayoutManager and StaggeredGridLayoutManager");
    }

    switch (ev.getAction()) {
        case MotionEvent.ACTION_DOWN:
            downX = ev.getX();
            downY = ev.getY();
            //如果滑动到了最底部，就允许继续向上滑动加载下一页，否者不允许
            getParent().requestDisallowInterceptTouchEvent(true);
            break;
        case MotionEvent.ACTION_MOVE:
            float dx = ev.getX() - downX;
            float dy = ev.getY() - downY;
            boolean allowParentTouchEvent;
            if (Math.abs(dy) > Math.abs(dx)) {
                if (dy > 0) {
                    //位于顶部时下拉，让父View消费事件
                    allowParentTouchEvent = isTop = firstVisibleItemPosition == 0 && getChildAt(0).getTop() >= 0;
                } else {
                    //位于底部时上拉，让父View消费事件
                    int visibleItemCount = layoutManager.getChildCount();
                    int totalItemCount = layoutManager.getItemCount();
                    allowParentTouchEvent = isBottom = visibleItemCount > 0 && (lastVisibleItemPosition) >= totalItemCount - 1 && getChildAt(getChildCount() - 1).getBottom() <= getHeight();
                }
            } else {
                //水平方向滑动
                allowParentTouchEvent = true;
            }
            getParent().requestDisallowInterceptTouchEvent(!allowParentTouchEvent);
    }
    return super.dispatchTouchEvent(ev);

}

源代码10 项目： YCShopDetailLayout 文件： VerticalRecyclerView.java

@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
    RecyclerView.LayoutManager layoutManager = getLayoutManager();
    if (layoutManager != null) {
        if (layoutManager instanceof GridLayoutManager) {
            lastVisibleItemPosition = ((GridLayoutManager) layoutManager).findLastVisibleItemPosition();
            firstVisibleItemPosition = ((GridLayoutManager) layoutManager).findFirstVisibleItemPosition();
        } else if (layoutManager instanceof LinearLayoutManager) {
            lastVisibleItemPosition = ((LinearLayoutManager) layoutManager).findLastVisibleItemPosition();
            firstVisibleItemPosition = ((LinearLayoutManager) layoutManager).findFirstVisibleItemPosition();
        } else if (layoutManager instanceof StaggeredGridLayoutManager) {
            StaggeredGridLayoutManager staggeredGridLayoutManager = (StaggeredGridLayoutManager) layoutManager;
            if (lastPositions == null) {
                lastPositions = new int[staggeredGridLayoutManager.getSpanCount()];
                firstPositions = new int[staggeredGridLayoutManager.getSpanCount()];
            }
            staggeredGridLayoutManager.findLastVisibleItemPositions(lastPositions);
            staggeredGridLayoutManager.findFirstVisibleItemPositions(firstPositions);
            lastVisibleItemPosition = findMax(lastPositions);
            firstVisibleItemPosition = findMin(firstPositions);
        }
    } else {
        throw new RuntimeException("Unsupported LayoutManager used. Valid ones are LinearLayoutManager, GridLayoutManager and StaggeredGridLayoutManager");
    }

    switch (ev.getAction()) {
        case MotionEvent.ACTION_DOWN:
            downX = ev.getX();
            downY = ev.getY();
            //如果滑动到了最底部，就允许继续向上滑动加载下一页，否者不允许
            getParent().requestDisallowInterceptTouchEvent(true);
            break;
        case MotionEvent.ACTION_MOVE:
            float dx = ev.getX() - downX;
            float dy = ev.getY() - downY;
            boolean allowParentTouchEvent;
            if (Math.abs(dy) > Math.abs(dx)) {
                if (dy > 0) {
                    //位于顶部时下拉，让父View消费事件
                    allowParentTouchEvent = isTop = firstVisibleItemPosition == 0 && getChildAt(0).getTop() >= 0;
                } else {
                    //位于底部时上拉，让父View消费事件
                    int visibleItemCount = layoutManager.getChildCount();
                    int totalItemCount = layoutManager.getItemCount();
                    allowParentTouchEvent = isBottom = visibleItemCount > 0 && (lastVisibleItemPosition) >= totalItemCount - 1 && getChildAt(getChildCount() - 1).getBottom() <= getHeight();
                }
            } else {
                //水平方向滑动
                allowParentTouchEvent = true;
            }
            getParent().requestDisallowInterceptTouchEvent(!allowParentTouchEvent);
            break;
        default:
            break;
    }
    return super.dispatchTouchEvent(ev);

}

源代码11 项目： ucar-weex-core 文件： WXRecyclerViewOnScrollListener.java

@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");
    }
  }
}

源代码12 项目： LazyRecyclerAdapter 文件： LoadMoreScrollListener.java

@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
    super.onScrolled(recyclerView, dx, dy);

    RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
    if (layoutManagerType == null) {
        if (layoutManager instanceof LinearLayoutManager) {
            layoutManagerType = LAYOUT_MANAGER_TYPE.LINEAR;
        } else if (layoutManager instanceof GridLayoutManager) {
            layoutManagerType = LAYOUT_MANAGER_TYPE.GRID;
        } else if (layoutManager instanceof StaggeredGridLayoutManager) {
            layoutManagerType = LAYOUT_MANAGER_TYPE.STAGGERED_GRID;
        } else {
            throw new RuntimeException("Unsupported");
        }
    }

    switch (layoutManagerType) {
        case LINEAR:
            lastVisibleItemPosition = ((LinearLayoutManager) layoutManager)
                    .findLastVisibleItemPosition();

            firstVisibleItemPosition = ((LinearLayoutManager) layoutManager)
                    .findFirstVisibleItemPosition();
            break;
        case GRID:
            lastVisibleItemPosition = ((GridLayoutManager) layoutManager)
                    .findLastVisibleItemPosition();
            firstVisibleItemPosition = ((GridLayoutManager) layoutManager)
                    .findFirstVisibleItemPosition();
            break;
        case STAGGERED_GRID:
            StaggeredGridLayoutManager staggeredGridLayoutManager
                    = (StaggeredGridLayoutManager) layoutManager;
            if (lastPositions == null) {
                lastPositions = new int[staggeredGridLayoutManager.getSpanCount()];
            }
            if (firstPositions == null) {
                firstPositions = new int[staggeredGridLayoutManager.getSpanCount()];
            }
            staggeredGridLayoutManager.findLastVisibleItemPositions(lastPositions);
            staggeredGridLayoutManager.findFirstVisibleItemPositions(firstPositions);
            lastVisibleItemPosition = findMax(lastPositions);
            firstVisibleItemPosition = findMin(firstPositions);
            break;
    }
    onScrolled(firstVisibleItemPosition);


}

方法所在类

android.support.v7.widget.StaggeredGridLayoutManager