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

/**
 * 平滑的滑动到指定位置
 */
private void smoothMoveToPosition(RecyclerView mRecyclerView, final int position) {
    // 第一个可见位置
    int firstItem = mRecyclerView.getChildLayoutPosition(mRecyclerView.getChildAt(0));
    // 最后一个可见位置
    int lastItem = mRecyclerView.getChildLayoutPosition(mRecyclerView.getChildAt(mRecyclerView.getChildCount() - 1));
    if (position < firstItem) {
        // 第一种可能:跳转位置在第一个可见位置之前
        mRecyclerView.smoothScrollToPosition(position);
    } else if (position <= lastItem) {
        //滑动指定高度
        mRecyclerView.smoothScrollBy(0, GetScreenWinth.getHeight(this) -
                (Resources.getSystem().getDimensionPixelSize(Resources.getSystem().getIdentifier("status_bar_height", "dimen", "android"))));
    } else {
        // 第三种可能:跳转位置在最后可见项之后
        mRecyclerView.smoothScrollToPosition(position);
    }
}
 

private void moveToPosition(LinearLayoutManager layoutManager, RecyclerView recyclerView, int position) {
    // 第一个可见的view的位置
    int firstItem = layoutManager.findFirstVisibleItemPosition();
    // 最后一个可见的view的位置
    int lastItem = layoutManager.findLastVisibleItemPosition();
    if (position <= firstItem) {
        // 如果跳转位置firstItem 之前(滑出屏幕的情况)，就smoothScrollToPosition可以直接跳转，
        recyclerView.smoothScrollToPosition(position);
    } else if (position <= lastItem) {
        // 跳转位置在firstItem 之后，lastItem 之间（显示在当前屏幕），smoothScrollBy来滑动到指定位置
        int top = recyclerView.getChildAt(position - firstItem).getTop();
        recyclerView.smoothScrollBy(0, top);
    } else {
        // 如果要跳转的位置在lastItem 之后，则先调用smoothScrollToPosition将要跳转的位置滚动到可见位置
        // 再通过onScrollStateChanged控制再次调用当前moveToPosition方法，执行上一个判断中的方法
        recyclerView.smoothScrollToPosition(position);
        scrollToPosition = position;
        canScroll = true;
    }
}
 

public WindowControl(Context context) {
    this.context = context;
    wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
    rootView = LayoutInflater.from(context).inflate(R.layout.window_display, null);
    mRecycleView = (RecyclerView) rootView;
    mRecycleView.setLayoutManager(new LinearLayoutManager(context));
    mAdapter = new LogcatAdapter(context);
    mRecycleView.setAdapter(mAdapter);

    observer = content -> {
        if (content != null) {
            if (isFirst) {
                content.setContent("init window");
            }

            if (!TextUtils.isEmpty(content.getContent())) {
                mAdapter.addData(content);
                mRecycleView.smoothScrollToPosition(mAdapter.getItemCount() - 1);
            }

            isFirst = false;
        }
    };
}
 

@Override
public boolean onAddFocusables(RecyclerView recyclerView, ArrayList<View> views, int direction, int focusableMode) {
    final int currentPosition = getCurrentPosition();
    final View currentView = findViewByPosition(currentPosition);
    if (currentView == null) return true;
    if (recyclerView.hasFocus()) {
        final int movement = getMovement(direction);
        if (movement != DIRECTION_NO_WHERE) {
            final int targetPosition = movement == DIRECTION_BACKWARD ?
                    currentPosition - 1 : currentPosition + 1;
            recyclerView.smoothScrollToPosition(targetPosition);
        }
    } else {
        currentView.addFocusables(views, direction, focusableMode);
    }
    return true;
}
 

@Override
        public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
            super.onScrollStateChanged(recyclerView, newState);
            if (RecyclerView.SCROLL_STATE_IDLE == newState) {
                View view = recyclerView.getChildAt(0);
//                Rect rect = new Rect();
//                Point point = new Point();
//                recyclerView.getChildVisibleRect(view, rect, point);
                if ((int)view.getTag() == CityWeatherAdapter.VIEW_MAIN) {
                    if (mScrollDown) {
                        recyclerView.smoothScrollToPosition(1);
                    } else {
                        recyclerView.smoothScrollToPosition(0);
                    }
                }
            }
        }
 

public FastScrollToTop(RecyclerView recyclerView, int threshold, int lastScroll, long scrollToPositionDelay) {
   this.lastScroll = lastScroll;

   if (recyclerView.getChildCount() == 0) {
      weakRecycler = null;
      return;
   }

   View v = recyclerView.getChildAt(0);
   int position = recyclerView.getChildAdapterPosition(v);
   if (position < threshold) {
      recyclerView.smoothScrollToPosition(0);
      weakRecycler = null;
      return;
   }

   // here is where the fun happens
   weakRecycler = new WeakReference<>(recyclerView);
   recyclerView.smoothScrollToPosition(0);
   recyclerView.postDelayed(runAfterSpeedUp, scrollToPositionDelay);
}
 

public void onRefresh() {
    RecyclerView mRecyclerView = this.recyclerView.getRecyclerView();
    int firstVisibleItemPosition = ((LinearLayoutManager)
            mRecyclerView.getLayoutManager()).findFirstVisibleItemPosition();
    if (firstVisibleItemPosition == 0) {
        onLazyLoad();
        return;
    }
    mRecyclerView.scrollToPosition(5);
    mRecyclerView.smoothScrollToPosition(0);
}
 

public void onRefresh() {
    RecyclerView mRecyclerView = recyclerView.getRecyclerView();
    int firstVisibleItemPosition = ((LinearLayoutManager)
            mRecyclerView.getLayoutManager()).findFirstVisibleItemPosition();
    if (firstVisibleItemPosition == 0) {
        onLazyLoad();
        return;
    }
    mRecyclerView.scrollToPosition(5);
    mRecyclerView.smoothScrollToPosition(0);
}
 

public static void scrollToPosition(int position, RecyclerView mRecyclerView, RecyclerView.Adapter mRecyclerAdapter) {
    int offsetOfScroll = getOffsetOfGoal(position, mRecyclerView, mRecyclerAdapter);
    if (offsetOfScroll < SMOOTH_SCROLL_IF_THIS_MUCH) {
        mRecyclerView.smoothScrollToPosition(position);
    } else {
        mRecyclerView.scrollToPosition(position);
    }
}
 

/**
 * 添加LoadMore布局
 */
private void addFooterLoadinLayout(RecyclerView recyclerView) {
    isLoading = true;
    if (null == mFooterLoadingLayout) {
        mFooterLoadingLayout = new RotateLoadingLayout(mContext, RecyclerMode.BOTTOM);
    }
    mAdapter.addFooterView(mFooterLoadingLayout);
    mOldItemCount = mAdapter.getItemCount();
    recyclerView.smoothScrollToPosition(mOldItemCount - 1);
    mFooterLoadingLayout.onRefresh();
    mFooterLoadingLayout.setVisibility(View.VISIBLE);
}
 

@BindingAdapter("app:position")
public static void setPosition(RecyclerView recyclerView, int position) {
    recyclerView.smoothScrollToPosition(position);
}
 

@Override
protected void onBackItemClicked(@NonNull final RecyclerView recyclerView, @NonNull final CarouselLayoutManager carouselLayoutManager, @NonNull final View v) {
    recyclerView.smoothScrollToPosition(carouselLayoutManager.getPosition(v));
}
 

@Override public void run() {
   RecyclerView recyclerView = weakRecycler.get();
   if (recyclerView == null) return;
   recyclerView.scrollToPosition(lastScroll);
   recyclerView.smoothScrollToPosition(0);
}
 

/**
 * Currently this simply calls recyclerView.smoothScrollToPosition(position);
 * But the API is already available and in the near future we'll try to code the `offset`
 *
 * @param recyclerView
 * @param position
 * @param offset
 */
public static void smoothScrollToPositionWithOffset(RecyclerView recyclerView, int position, int offset) {
   recyclerView.smoothScrollToPosition(position);
}