RecyclerView ItemTouchHelper

傷城~ 2022-07-14 11:58 139阅读 0赞

原文链接：[http://blog.csdn.net/tyk0910/article/details/51460808][http_blog.csdn.net_tyk0910_article_details_51460808]

![ItemTouchHelper][]

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent">
    
        <LinearLayout android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical">
    
            <TextView android:id="@+id/txt" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_margin="10dp" android:text="切换栏目" android:textSize="15dp"/>
    
            <View android:layout_width="match_parent" android:layout_height="1dp" android:background="@color/black"/>
    
            <ScrollView android:layout_width="match_parent" android:layout_height="match_parent" android:scrollbars="none">
    
                <LinearLayout android:id="@+id/tbs_ll" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical">
    
    
                    <android.support.v7.widget.RecyclerView android:id="@+id/chose_recycle" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginLeft="15dp" android:layout_marginTop="15dp" android:layout_weight="1"/>
    
    
                    <LinearLayout android:id="@+id/my_ll" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/chose_recycle" android:layout_centerVertical="true" android:background="@color/font_text">
    
                        <TextView android:id="@+id/second_txt" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_margin="10dp" android:text="点击添加更多栏目" android:textSize="15dp"/>
                    </LinearLayout>
    
    
                    <android.support.v7.widget.RecyclerView android:id="@+id/all_recycle" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/my_ll" android:layout_marginLeft="15dp" android:layout_marginTop="10dp"/>
    
                </LinearLayout>
            </ScrollView>
        </LinearLayout>
    </LinearLayout>

public interface onMoveAndSwipedListener { 
        boolean onItemMove(int fromPosition , int toPosition);
        void onItemDismiss(int position);
    }

public class SimpleItemTouchHelperCallback extends ItemTouchHelper.Callback { 
        private onMoveAndSwipedListener mAdapter;
    
    
        public SimpleItemTouchHelperCallback(onMoveAndSwipedListener listener) {
            mAdapter = listener;
        }
    
    
        /** * 这个方法是用来设置我们拖动的方向以及侧滑的方向的 */
        @Override
        public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
            //如果是ListView样式的RecyclerView
            //设置拖拽方向为上下
            final int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN |
                    ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT;
            //设置侧滑方向为从左到右和从右到左都可以
            final int swipeFlags = ItemTouchHelper.START | ItemTouchHelper.END;
            //将方向参数设置进去
            return makeMovementFlags(dragFlags, swipeFlags);
    
        }
    
        /** * 当我们拖动item时会回调此方法 */
        @Override
        public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
    
            //如果两个item不是一个类型的，我们让他不可以拖拽
            if (viewHolder.getItemViewType() != target.getItemViewType()) {
                return false;
            }
            //回调adapter中的onItemMove方法
            mAdapter.onItemMove(viewHolder.getAdapterPosition(), target.getAdapterPosition());
            return true;
        }
    
        /** * 当我们侧滑item时会回调此方法 */
        @Override
        public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
            mAdapter.onItemDismiss(viewHolder.getAdapterPosition());
        }
    
    }

public class WangYiActivity extends AppCompatActivity implements AllTabsAdapter.onAllTabsListener { 
    
    
            public static List<String> choseTabs = new ArrayList<>();
            public static List<String> allTabs = new ArrayList<>();
    
    
            private RecyclerView choseRecycle, allRecycle;
            private ChoseTabsAdapter choseAdapter;
            private AllTabsAdapter   allAdapter;
            private LinearLayout     linearLayout;
            private ItemTouchHelper  mItemTouchHelper;
    
            @Override
            protected void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_wang_yi);
                initviews();
                initdatas();
            }
    
            private void initdatas() {
                choseTabs.add("头条");
                choseTabs.add("科技");
                choseTabs.add("热点");
                choseTabs.add("政务");
                choseTabs.add("移动互联");
                choseTabs.add("军事");
                choseTabs.add("历史");
                choseTabs.add("社会");
                choseTabs.add("财经");
                choseTabs.add("娱乐");
    
    
                allTabs.add("体育");
                allTabs.add("时尚");
                allTabs.add("房产");
                allTabs.add("论坛");
                allTabs.add("博客");
                allTabs.add("健康");
                allTabs.add("轻松一刻");
                allTabs.add("直播");
                allTabs.add("段子");
                allTabs.add("彩票");
                allTabs.add("直播");
                allTabs.add("段子");
                allTabs.add("彩票");
                allTabs.add("直播");
                allTabs.add("段子");
                allTabs.add("彩票");
                allTabs.add("轻松一刻");
                allTabs.add("直播");
                allTabs.add("段子");
                allTabs.add("彩票");
                allTabs.add("直播");
                allTabs.add("段子");
                allTabs.add("彩票");
                allTabs.add("直播");
                allTabs.add("段子");
                allTabs.add("彩票");
    
            }
    
    
            private void initviews() {
    
                choseTabs.clear();
                allTabs.clear();
    
                linearLayout = (LinearLayout) findViewById(R.id.tbs_ll);
    
                choseRecycle = (RecyclerView) findViewById(R.id.chose_recycle);
                allRecycle = (RecyclerView) findViewById(R.id.all_recycle);
                choseAdapter = new ChoseTabsAdapter(this);
                allAdapter = new AllTabsAdapter(this);
                allAdapter.setListener(this);
    
                choseRecycle.setLayoutManager(new GridLayoutManager(this, 4));
                allRecycle.setLayoutManager(new GridLayoutManager(this, 4));
    
                choseRecycle.addItemDecoration(new SpaceItemDecoration(15));
                allRecycle.addItemDecoration(new SpaceItemDecoration(15));
    
                choseRecycle.setAdapter(choseAdapter);
                allRecycle.setAdapter(allAdapter);
    
    
                //关联ItemTouchHelper和RecyclerView
                ItemTouchHelper.Callback callback = new SimpleItemTouchHelperCallback(choseAdapter);
                mItemTouchHelper = new ItemTouchHelper(callback);
                mItemTouchHelper.attachToRecyclerView(choseRecycle);
    
            }
    
    
            @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
            @Override
            public void allTabsItemClick(final View view, final int position) {
    
    
                final PathMeasure mPathMeasure;
                final float[] mCurrentPosition = new float[2];
                int parentLoc[] = new int[2];
                linearLayout.getLocationInWindow(parentLoc);
    
                int startLoc[] = new int[2];
                view.getLocationInWindow(startLoc);
    
                final View startView = view;
                startView.setLayoutParams(new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT));
                // RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(view.getWidth(), view.getHeight());
                Log.e("tag", startView.getWidth() + "#" + startView.getHeight());
                allRecycle.removeView(view);
                linearLayout.addView(startView);
    
    
                // ImageView imageView = new ImageView(this);
                // imageView.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT));
                // imageView.setImageResource(R.drawable.location_located);
                // linearLayout.addView(imageView);
    
                final View endView;
                float toX, toY;
                int endLoc[] = new int[2];
                //进行判断
                int i = choseTabs.size();
    
                if (i == 0) {
                    toX = view.getWidth();
                    toY = view.getHeight();
                } else if (i % 4 == 0) {
                    endView = choseRecycle.getChildAt(i - 4);
                    endView.getLocationInWindow(endLoc);
                    toX = endLoc[0] - parentLoc[0];
                    toY = endLoc[1] + view.getHeight() - parentLoc[1];
                } else {
                    endView = choseRecycle.getChildAt(i - 1);
                    endView.getLocationInWindow(endLoc);
                    toX = endLoc[0] + view.getWidth() - parentLoc[0];
                    toY = endLoc[1] - parentLoc[1];
                }
    
                float startX = startLoc[0] - parentLoc[0];
                float startY = startLoc[1] - parentLoc[1];
    
                Path path = new Path();
                path.moveTo(startX, startY);
                path.lineTo(toX, toY);
                mPathMeasure = new PathMeasure(path, false);
    
    
                //属性动画实现
                ValueAnimator valueAnimator = ValueAnimator.ofFloat(0, mPathMeasure.getLength());
                valueAnimator.setDuration(500);
                // 匀速插值器
                valueAnimator.setInterpolator(new LinearInterpolator());
                valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
                    @Override
                    public void onAnimationUpdate(ValueAnimator animation) {
                        float value = (Float) animation.getAnimatedValue();
                        // 获取当前点坐标封装到mCurrentPosition
                        mPathMeasure.getPosTan(value, mCurrentPosition, null);
                        startView.setTranslationX(mCurrentPosition[0]);
                        startView.setTranslationY(mCurrentPosition[1]);
                        Log.e("tag", mCurrentPosition[0] + "@" + mCurrentPosition[1]);
    
                    }
                });
                valueAnimator.start();
    
                valueAnimator.addListener(new Animator.AnimatorListener() {
                    @Override
                    public void onAnimationStart(Animator animation) {
    
                    }
    
                    @Override
                    public void onAnimationEnd(Animator animation) {
    
                        //默认recyclerviewe的动画
                        allRecycle.setItemAnimator(new DefaultItemAnimator());
                        choseRecycle.setItemAnimator(new DefaultItemAnimator());
                        choseTabs.add(choseTabs.size(), allTabs.get(position));
                        allTabs.remove(position);
                        //先更新数据
                        allAdapter.notifyDataSetChanged();
                        choseAdapter.notifyDataSetChanged();
                        //再更新动画
                        allAdapter.notifyItemRemoved(position);
                        choseAdapter.notifyItemInserted(choseTabs.size());
                        linearLayout.removeView(startView);
                    }
    
                    @Override
                    public void onAnimationCancel(Animator animation) {
    
                    }
    
                    @Override
                    public void onAnimationRepeat(Animator animation) {
                    }
                });
            }
        }

原文链接：[http://www.jianshu.com/p/d30fd8da4eac][http_www.jianshu.com_p_d30fd8da4eac]

使用ItemTouchHelper高效地实现 今日头条 、网易新闻 的频道排序、移动

![ItemTouchHelper][ItemTouchHelper 1]

/** * ItemDragHelperCallback * Created by YoKeyword on 15/12/29. */
    public class ItemDragHelperCallback extends ItemTouchHelper.Callback { 
    
        @Override
        public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
            int dragFlags;
            RecyclerView.LayoutManager manager = recyclerView.getLayoutManager();
            if (manager instanceof GridLayoutManager || manager instanceof StaggeredGridLayoutManager) {
                dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN | ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT;
            } else {
                dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;
            }
            // 如果想支持滑动(删除)操作, swipeFlags = ItemTouchHelper.START | ItemTouchHelper.END
            int swipeFlags = 0;
            return makeMovementFlags(dragFlags, swipeFlags);
        }
    
        @Override
        public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
            // 不同Type之间不可移动
            if (viewHolder.getItemViewType() != target.getItemViewType()) {
                return false;
            }
    
            if (recyclerView.getAdapter() instanceof OnItemMoveListener) {
                OnItemMoveListener listener = ((OnItemMoveListener) recyclerView.getAdapter());
                listener.onItemMove(viewHolder.getAdapterPosition(), target.getAdapterPosition());
            }
            return true;
        }
    
        @Override
        public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
    
        }
    
        @Override
        public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {
            // 不在闲置状态
            if (actionState != ItemTouchHelper.ACTION_STATE_IDLE) {
                if (viewHolder instanceof OnDragVHListener) {
                    OnDragVHListener itemViewHolder = (OnDragVHListener) viewHolder;
                    itemViewHolder.onItemSelected();
                }
            }
            super.onSelectedChanged(viewHolder, actionState);
        }
    
        @Override
        public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
            if (viewHolder instanceof OnDragVHListener) {
                OnDragVHListener itemViewHolder = (OnDragVHListener) viewHolder;
                itemViewHolder.onItemFinish();
            }
            super.clearView(recyclerView, viewHolder);
        }
    
        @Override
        public boolean isLongPressDragEnabled() {
            // 不支持长按拖拽功能 手动控制
            return false;
        }
    
        @Override
        public boolean isItemViewSwipeEnabled() {
            // 不支持滑动功能
            return false;
        }
    }

/** * ViewHolder 被选中 以及 拖拽释放 触发监听器 * Created by YoKeyword on 15/12/29. */
    public interface OnDragVHListener { 
        /** * Item被选中时触发 */
        void onItemSelected();
    
    
        /** * Item在拖拽结束/滑动结束后触发 */
        void onItemFinish();
    }

/** * Item移动后 触发 * Created by YoKeyword on 15/12/28. */
    public interface OnItemMoveListener { 
        void onItemMove(int fromPosition, int toPosition);
    }

/** * 频道 增删改查 排序 * Created by YoKeyword on 15/12/29. */
    public class ChannelActivity extends AppCompatActivity { 
    
        private RecyclerView mRecy;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_demo);
    
            mRecy = (RecyclerView) findViewById(R.id.recy);
            init();
        }
    
        private void init() {
            final List<ChannelEntity> items = new ArrayList<>();
            for (int i = 0; i < 18; i++) {
                ChannelEntity entity = new ChannelEntity();
                entity.setName("频道" + i);
                items.add(entity);
            }
            final List<ChannelEntity> otherItems = new ArrayList<>();
            for (int i = 0; i < 20; i++) {
                ChannelEntity entity = new ChannelEntity();
                entity.setName("其他" + i);
                otherItems.add(entity);
            }
    
            GridLayoutManager manager = new GridLayoutManager(this, 4);
            mRecy.setLayoutManager(manager);
    
            ItemDragHelperCallback callback = new ItemDragHelperCallback();
            final ItemTouchHelper helper = new ItemTouchHelper(callback);
            helper.attachToRecyclerView(mRecy);
    
            final ChannelAdapter adapter = new ChannelAdapter(this, helper, items, otherItems);
            manager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
                @Override
                public int getSpanSize(int position) {
                    int viewType = adapter.getItemViewType(position);
                    return viewType == ChannelAdapter.TYPE_MY || viewType == ChannelAdapter.TYPE_OTHER ? 1 : 4;
                }
            });
            mRecy.setAdapter(adapter);
    
            adapter.setOnMyChannelItemClickListener(new ChannelAdapter.OnMyChannelItemClickListener() {
                @Override
                public void onItemClick(View v, int position) {
                    Toast.makeText(ChannelActivity.this, items.get(position).getName(), Toast.LENGTH_SHORT).show();
                }
            });
        }
    }

/** * 拖拽排序 + 增删 * Created by YoKeyword on 15/12/28. */
    public class ChannelAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> implements OnItemMoveListener { 
        // 我的频道 标题部分
        public static final int TYPE_MY_CHANNEL_HEADER = 0;
        // 我的频道
        public static final int TYPE_MY = 1;
        // 其他频道 标题部分
        public static final int TYPE_OTHER_CHANNEL_HEADER = 2;
        // 其他频道
        public static final int TYPE_OTHER = 3;
    
        // 我的频道之前的header数量 该demo中 即标题部分 为 1
        private static final int COUNT_PRE_MY_HEADER = 1;
        // 其他频道之前的header数量 该demo中 即标题部分 为 COUNT_PRE_MY_HEADER + 1
        private static final int COUNT_PRE_OTHER_HEADER = COUNT_PRE_MY_HEADER + 1;
    
        private static final long ANIM_TIME = 360L;
    
        // touch 点击开始时间
        private long startTime;
        // touch 间隔时间 用于分辨是否是 "点击"
        private static final long SPACE_TIME = 100;
    
        private LayoutInflater mInflater;
        private ItemTouchHelper mItemTouchHelper;
    
        // 是否为 编辑 模式
        private boolean isEditMode;
    
        private List<ChannelEntity> mMyChannelItems, mOtherChannelItems;
    
        // 我的频道点击事件
        private OnMyChannelItemClickListener mChannelItemClickListener;
    
        public ChannelAdapter(Context context, ItemTouchHelper helper, List<ChannelEntity> mMyChannelItems, List<ChannelEntity> mOtherChannelItems) {
            this.mInflater = LayoutInflater.from(context);
            this.mItemTouchHelper = helper;
            this.mMyChannelItems = mMyChannelItems;
            this.mOtherChannelItems = mOtherChannelItems;
        }
    
        @Override
        public int getItemViewType(int position) {
            if (position == 0) {    // 我的频道 标题部分
                return TYPE_MY_CHANNEL_HEADER;
            } else if (position == mMyChannelItems.size() + 1) {    // 其他频道 标题部分
                return TYPE_OTHER_CHANNEL_HEADER;
            } else if (position > 0 && position < mMyChannelItems.size() + 1) {
                return TYPE_MY;
            } else {
                return TYPE_OTHER;
            }
        }
    
        @Override
        public RecyclerView.ViewHolder onCreateViewHolder(final ViewGroup parent, int viewType) {
            final View view;
            switch (viewType) {
                case TYPE_MY_CHANNEL_HEADER:
                    view = mInflater.inflate(R.layout.item_my_channel_header, parent, false);
                    final MyChannelHeaderViewHolder holder = new MyChannelHeaderViewHolder(view);
                    holder.tvBtnEdit.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            if (!isEditMode) {
                                startEditMode((RecyclerView) parent);
                                holder.tvBtnEdit.setText(R.string.finish);
                            } else {
                                cancelEditMode((RecyclerView) parent);
                                holder.tvBtnEdit.setText(R.string.edit);
                            }
                        }
                    });
                    return holder;
    
                case TYPE_MY:
                    view = mInflater.inflate(R.layout.item_my, parent, false);
                    final MyViewHolder myHolder = new MyViewHolder(view);
    
                    myHolder.textView.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(final View v) {
                            int position = myHolder.getAdapterPosition();
                            if (isEditMode) {
                                RecyclerView recyclerView = ((RecyclerView) parent);
                                View targetView = recyclerView.getLayoutManager().findViewByPosition(mMyChannelItems.size() + COUNT_PRE_OTHER_HEADER);
                                View currentView = recyclerView.getLayoutManager().findViewByPosition(position);
                                // 如果targetView不在屏幕内,则indexOfChild为-1 此时不需要添加动画,因为此时notifyItemMoved自带一个向目标移动的动画
                                // 如果在屏幕内,则添加一个位移动画
                                if (recyclerView.indexOfChild(targetView) >= 0) {
                                    int targetX, targetY;
    
                                    RecyclerView.LayoutManager manager = recyclerView.getLayoutManager();
                                    int spanCount = ((GridLayoutManager) manager).getSpanCount();
    
                                    // 移动后 高度将变化 (我的频道Grid 最后一个item在新的一行第一个)
                                    if ((mMyChannelItems.size() - COUNT_PRE_MY_HEADER) % spanCount == 0) {
                                        View preTargetView = recyclerView.getLayoutManager().findViewByPosition(mMyChannelItems.size() + COUNT_PRE_OTHER_HEADER - 1);
                                        targetX = preTargetView.getLeft();
                                        targetY = preTargetView.getTop();
                                    } else {
                                        targetX = targetView.getLeft();
                                        targetY = targetView.getTop();
                                    }
    
                                    moveMyToOther(myHolder);
                                    startAnimation(recyclerView, currentView, targetX, targetY);
    
                                } else {
                                    moveMyToOther(myHolder);
                                }
                            } else {
                                mChannelItemClickListener.onItemClick(v, position - COUNT_PRE_MY_HEADER);
                            }
                        }
                    });
    
                    myHolder.textView.setOnLongClickListener(new View.OnLongClickListener() {
                        @Override
                        public boolean onLongClick(final View v) {
                            if (!isEditMode) {
                                RecyclerView recyclerView = ((RecyclerView) parent);
                                startEditMode(recyclerView);
    
                                // header 按钮文字 改成 "完成"
                                View view = recyclerView.getChildAt(0);
                                if (view == recyclerView.getLayoutManager().findViewByPosition(0)) {
                                    TextView tvBtnEdit = (TextView) view.findViewById(R.id.tv_btn_edit);
                                    tvBtnEdit.setText(R.string.finish);
                                }
                            }
    
                            mItemTouchHelper.startDrag(myHolder);
                            return true;
                        }
                    });
    
                    myHolder.textView.setOnTouchListener(new View.OnTouchListener() {
                        @Override
                        public boolean onTouch(View v, MotionEvent event) {
                            if (isEditMode) {
                                switch (MotionEventCompat.getActionMasked(event)) {
                                    case MotionEvent.ACTION_DOWN:
                                        startTime = System.currentTimeMillis();
                                        break;
                                    case MotionEvent.ACTION_MOVE:
                                        if (System.currentTimeMillis() - startTime > SPACE_TIME) {
                                            mItemTouchHelper.startDrag(myHolder);
                                        }
                                        break;
                                    case MotionEvent.ACTION_CANCEL:
                                    case MotionEvent.ACTION_UP:
                                        startTime = 0;
                                        break;
                                }
    
                            }
                            return false;
                        }
                    });
                    return myHolder;
    
                case TYPE_OTHER_CHANNEL_HEADER:
                    view = mInflater.inflate(R.layout.item_other_channel_header, parent, false);
                    return new RecyclerView.ViewHolder(view) {
                    };
    
                case TYPE_OTHER:
                    view = mInflater.inflate(R.layout.item_other, parent, false);
                    final OtherViewHolder otherHolder = new OtherViewHolder(view);
                    otherHolder.textView.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            RecyclerView recyclerView = ((RecyclerView) parent);
                            RecyclerView.LayoutManager manager = recyclerView.getLayoutManager();
                            int currentPiosition = otherHolder.getAdapterPosition();
                            // 如果RecyclerView滑动到底部,移动的目标位置的y轴 - height
                            View currentView = manager.findViewByPosition(currentPiosition);
                            // 目标位置的前一个item 即当前MyChannel的最后一个
                            View preTargetView = manager.findViewByPosition(mMyChannelItems.size() - 1 + COUNT_PRE_MY_HEADER);
    
                            // 如果targetView不在屏幕内,则为-1 此时不需要添加动画,因为此时notifyItemMoved自带一个向目标移动的动画
                            // 如果在屏幕内,则添加一个位移动画
                            if (recyclerView.indexOfChild(preTargetView) >= 0) {
                                int targetX = preTargetView.getLeft();
                                int targetY = preTargetView.getTop();
    
                                int targetPosition = mMyChannelItems.size() - 1 + COUNT_PRE_OTHER_HEADER;
    
                                GridLayoutManager gridLayoutManager = ((GridLayoutManager) manager);
                                int spanCount = gridLayoutManager.getSpanCount();
                                // target 在最后一行第一个
                                if ((targetPosition - COUNT_PRE_MY_HEADER) % spanCount == 0) {
                                    View targetView = manager.findViewByPosition(targetPosition);
                                    targetX = targetView.getLeft();
                                    targetY = targetView.getTop();
                                } else {
                                    targetX += preTargetView.getWidth();
    
                                    // 最后一个item可见
                                    if (gridLayoutManager.findLastVisibleItemPosition() == getItemCount() - 1) {
                                        // 最后的item在最后一行第一个位置
                                        if ((getItemCount() - 1 - mMyChannelItems.size() - COUNT_PRE_OTHER_HEADER) % spanCount == 0) {
                                            // RecyclerView实际高度 > 屏幕高度 && RecyclerView实际高度 < 屏幕高度 + item.height
                                            int firstVisiblePostion = gridLayoutManager.findFirstVisibleItemPosition();
                                            if (firstVisiblePostion == 0) {
                                                // FirstCompletelyVisibleItemPosition == 0 即 内容不满一屏幕 , targetY值不需要变化
                                                // // FirstCompletelyVisibleItemPosition != 0 即 内容满一屏幕 并且 可滑动 , targetY值 + firstItem.getTop
                                                if (gridLayoutManager.findFirstCompletelyVisibleItemPosition() != 0) {
                                                    int offset = (-recyclerView.getChildAt(0).getTop()) - recyclerView.getPaddingTop();
                                                    targetY += offset;
                                                }
                                            } else { // 在这种情况下 并且 RecyclerView高度变化时(即可见第一个item的 position != 0),
                                                // 移动后, targetY值 + 一个item的高度
                                                targetY += preTargetView.getHeight();
                                            }
                                        }
                                    } else {
                                        System.out.println("current--No");
                                    }
                                }
    
                                // 如果当前位置是otherChannel可见的最后一个
                                // 并且 当前位置不在grid的第一个位置
                                // 并且 目标位置不在grid的第一个位置
    
                                // 则 需要延迟250秒 notifyItemMove , 这是因为这种情况 , 并不触发ItemAnimator , 会直接刷新界面
                                // 导致我们的位移动画刚开始,就已经notify完毕,引起不同步问题
                                if (currentPiosition == gridLayoutManager.findLastVisibleItemPosition()
                                        && (currentPiosition - mMyChannelItems.size() - COUNT_PRE_OTHER_HEADER) % spanCount != 0
                                        && (targetPosition - COUNT_PRE_MY_HEADER) % spanCount != 0) {
                                    moveOtherToMyWithDelay(otherHolder);
                                } else {
                                    moveOtherToMy(otherHolder);
                                }
                                startAnimation(recyclerView, currentView, targetX, targetY);
    
                            } else {
                                moveOtherToMy(otherHolder);
                            }
                        }
                    });
                    return otherHolder;
            }
            return null;
        }
    
        @Override
        public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
            if (holder instanceof MyViewHolder) {
    
                MyViewHolder myHolder = (MyViewHolder) holder;
                myHolder.textView.setText(mMyChannelItems.get(position - COUNT_PRE_MY_HEADER).getName());
                if (isEditMode) {
                    myHolder.imgEdit.setVisibility(View.VISIBLE);
                } else {
                    myHolder.imgEdit.setVisibility(View.INVISIBLE);
                }
    
            } else if (holder instanceof OtherViewHolder) {
    
                ((OtherViewHolder) holder).textView.setText(mOtherChannelItems.get(position - mMyChannelItems.size() - COUNT_PRE_OTHER_HEADER).getName());
    
            } else if (holder instanceof MyChannelHeaderViewHolder) {
    
                MyChannelHeaderViewHolder headerHolder = (MyChannelHeaderViewHolder) holder;
                if (isEditMode) {
                    headerHolder.tvBtnEdit.setText(R.string.finish);
                } else {
                    headerHolder.tvBtnEdit.setText(R.string.edit);
                }
            }
        }
    
        @Override
        public int getItemCount() {
            // 我的频道 标题 + 我的频道.size + 其他频道 标题 + 其他频道.size
            return mMyChannelItems.size() + mOtherChannelItems.size() + COUNT_PRE_OTHER_HEADER;
        }
    
        /** * 开始增删动画 */
        private void startAnimation(RecyclerView recyclerView, final View currentView, float targetX, float targetY) {
            final ViewGroup viewGroup = (ViewGroup) recyclerView.getParent();
            final ImageView mirrorView = addMirrorView(viewGroup, recyclerView, currentView);
    
            Animation animation = getTranslateAnimator(
                    targetX - currentView.getLeft(), targetY - currentView.getTop());
            currentView.setVisibility(View.INVISIBLE);
            mirrorView.startAnimation(animation);
    
            animation.setAnimationListener(new Animation.AnimationListener() {
                @Override
                public void onAnimationStart(Animation animation) {
                }
    
                @Override
                public void onAnimationEnd(Animation animation) {
                    viewGroup.removeView(mirrorView);
                    if (currentView.getVisibility() == View.INVISIBLE) {
                        currentView.setVisibility(View.VISIBLE);
                    }
                }
    
                @Override
                public void onAnimationRepeat(Animation animation) {
    
                }
            });
        }
    
        /** * 我的频道 移动到 其他频道 * * @param myHolder */
        private void moveMyToOther(MyViewHolder myHolder) {
            int position = myHolder.getAdapterPosition();
    
            int startPosition = position - COUNT_PRE_MY_HEADER;
            if (startPosition > mMyChannelItems.size() - 1) {
                return;
            }
            ChannelEntity item = mMyChannelItems.get(startPosition);
            mMyChannelItems.remove(startPosition);
            mOtherChannelItems.add(0, item);
    
            notifyItemMoved(position, mMyChannelItems.size() + COUNT_PRE_OTHER_HEADER);
        }
    
        /** * 其他频道 移动到 我的频道 * * @param otherHolder */
        private void moveOtherToMy(OtherViewHolder otherHolder) {
            int position = processItemRemoveAdd(otherHolder);
            if (position == -1) {
                return;
            }
            notifyItemMoved(position, mMyChannelItems.size() - 1 + COUNT_PRE_MY_HEADER);
        }
    
        /** * 其他频道 移动到 我的频道 伴随延迟 * * @param otherHolder */
        private void moveOtherToMyWithDelay(OtherViewHolder otherHolder) {
            final int position = processItemRemoveAdd(otherHolder);
            if (position == -1) {
                return;
            }
            delayHandler.postDelayed(new Runnable() {
                @Override
                public void run() {
                    notifyItemMoved(position, mMyChannelItems.size() - 1 + COUNT_PRE_MY_HEADER);
                }
            }, ANIM_TIME);
        }
    
        private Handler delayHandler = new Handler();
    
        private int processItemRemoveAdd(OtherViewHolder otherHolder) {
            int position = otherHolder.getAdapterPosition();
    
            int startPosition = position - mMyChannelItems.size() - COUNT_PRE_OTHER_HEADER;
            if (startPosition > mOtherChannelItems.size() - 1) {
                return -1;
            }
            ChannelEntity item = mOtherChannelItems.get(startPosition);
            mOtherChannelItems.remove(startPosition);
            mMyChannelItems.add(item);
            return position;
        }
    
    
        /** * 添加需要移动的 镜像View */
        private ImageView addMirrorView(ViewGroup parent, RecyclerView recyclerView, View view) {
            /** * 我们要获取cache首先要通过setDrawingCacheEnable方法开启cache，然后再调用getDrawingCache方法就可以获得view的cache图片了。 buildDrawingCache方法可以不用调用，因为调用getDrawingCache方法时，若果cache没有建立，系统会自动调用buildDrawingCache方法生成cache。 若想更新cache, 必须要调用destoryDrawingCache方法把旧的cache销毁，才能建立新的。 当调用setDrawingCacheEnabled方法设置为false, 系统也会自动把原来的cache销毁。 */
            view.destroyDrawingCache();
            view.setDrawingCacheEnabled(true);
            final ImageView mirrorView = new ImageView(recyclerView.getContext());
            Bitmap bitmap = Bitmap.createBitmap(view.getDrawingCache());
            mirrorView.setImageBitmap(bitmap);
            view.setDrawingCacheEnabled(false);
            int[] locations = new int[2];
            view.getLocationOnScreen(locations);
            int[] parenLocations = new int[2];
            recyclerView.getLocationOnScreen(parenLocations);
            FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(bitmap.getWidth(), bitmap.getHeight());
            params.setMargins(locations[0], locations[1] - parenLocations[1], 0, 0);
            parent.addView(mirrorView, params);
    
            return mirrorView;
        }
    
        @Override
        public void onItemMove(int fromPosition, int toPosition) {
            ChannelEntity item = mMyChannelItems.get(fromPosition - COUNT_PRE_MY_HEADER);
            mMyChannelItems.remove(fromPosition - COUNT_PRE_MY_HEADER);
            mMyChannelItems.add(toPosition - COUNT_PRE_MY_HEADER, item);
            notifyItemMoved(fromPosition, toPosition);
        }
    
        /** * 开启编辑模式 * * @param parent */
        private void startEditMode(RecyclerView parent) {
            isEditMode = true;
    
            int visibleChildCount = parent.getChildCount();
            for (int i = 0; i < visibleChildCount; i++) {
                View view = parent.getChildAt(i);
                ImageView imgEdit = (ImageView) view.findViewById(R.id.img_edit);
                if (imgEdit != null) {
                    imgEdit.setVisibility(View.VISIBLE);
                }
            }
        }
    
        /** * 完成编辑模式 * * @param parent */
        private void cancelEditMode(RecyclerView parent) {
            isEditMode = false;
    
            int visibleChildCount = parent.getChildCount();
            for (int i = 0; i < visibleChildCount; i++) {
                View view = parent.getChildAt(i);
                ImageView imgEdit = (ImageView) view.findViewById(R.id.img_edit);
                if (imgEdit != null) {
                    imgEdit.setVisibility(View.INVISIBLE);
                }
            }
        }
    
        /** * 获取位移动画 */
        private TranslateAnimation getTranslateAnimator(float targetX, float targetY) {
            TranslateAnimation translateAnimation = new TranslateAnimation(
                    Animation.RELATIVE_TO_SELF, 0f,
                    Animation.ABSOLUTE, targetX,
                    Animation.RELATIVE_TO_SELF, 0f,
                    Animation.ABSOLUTE, targetY);
            // RecyclerView默认移动动画250ms 这里设置360ms 是为了防止在位移动画结束后 remove(view)过早 导致闪烁
            translateAnimation.setDuration(ANIM_TIME);
            translateAnimation.setFillAfter(true);
            return translateAnimation;
        }
    
        interface OnMyChannelItemClickListener {
            void onItemClick(View v, int position);
        }
    
        public void setOnMyChannelItemClickListener(OnMyChannelItemClickListener listener) {
            this.mChannelItemClickListener = listener;
        }
    
        /** * 我的频道 */
        class MyViewHolder extends RecyclerView.ViewHolder implements OnDragVHListener {
            private TextView textView;
            private ImageView imgEdit;
    
            public MyViewHolder(View itemView) {
                super(itemView);
                textView = (TextView) itemView.findViewById(R.id.tv);
                imgEdit = (ImageView) itemView.findViewById(R.id.img_edit);
            }
    
            /** * item 被选中时 */
            @Override
            public void onItemSelected() {
                textView.setBackgroundResource(R.drawable.bg_channel_p);
            }
    
            /** * item 取消选中时 */
            @Override
            public void onItemFinish() {
                textView.setBackgroundResource(R.drawable.bg_channel);
            }
        }
    
        /** * 其他频道 */
        class OtherViewHolder extends RecyclerView.ViewHolder {
            private TextView textView;
    
            public OtherViewHolder(View itemView) {
                super(itemView);
                textView = (TextView) itemView.findViewById(R.id.tv);
            }
        }
    
        /** * 我的频道 标题部分 */
        class MyChannelHeaderViewHolder extends RecyclerView.ViewHolder {
            private TextView tvBtnEdit;
    
            public MyChannelHeaderViewHolder(View itemView) {
                super(itemView);
                tvBtnEdit = (TextView) itemView.findViewById(R.id.tv_btn_edit);
            }
        }
    }

/** * 频道实体类 * Created by YoKeyword on 15/12/29. */
    public class ChannelEntity { 
    
        private long id;
        private String name;
    
        public long getId() {
            return id;
        }
    
        public void setId(long id) {
            this.id = id;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    }

## item\_my\_channel\_header.xml ##

<?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="48dp">
    
        <TextView android:id="@+id/tv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:layout_marginLeft="16dp" android:text="@string/my_cahnnel" android:textSize="16sp"/>
    
        <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignBottom="@id/tv" android:layout_marginLeft="16dp" android:layout_toRightOf="@id/tv" android:text="@string/tip_drag" android:textColor="@color/tip" android:textSize="12sp"/>
    
        <TextView android:id="@+id/tv_btn_edit" android:layout_width="56dp" android:layout_height="30dp" android:layout_centerVertical="true" android:layout_alignParentRight="true" android:layout_marginRight="8dp" android:gravity="center" android:textSize="13sp" android:background="@drawable/bg_btn" android:textColor="@color/red_500" android:text="@string/edit"/>
    
        <View android:layout_width="match_parent" android:layout_height="0.3dp" android:layout_alignParentBottom="true" android:background="@color/tip"/>
    </RelativeLayout>

## item\_other\_channel\_header.xml ##

## item\_my.xml ##

<?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="wrap_content" android:layout_height="wrap_content">
    
        <TextView android:id="@+id/tv" android:layout_width="match_parent" android:layout_height="36dp" android:layout_margin="8dp" android:background="@drawable/bg_channel" android:foreground="?attr/selectableItemBackground" android:layout_centerInParent="true" android:gravity="center"/>
    
        <ImageView android:id="@+id/img_edit" android:layout_alignParentRight="true" android:layout_width="16dp" android:layout_height="16dp" android:src="@mipmap/ic_channel_edit"/>
    
    </RelativeLayout>

## item\_other.xml ##

<?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="wrap_content" android:layout_height="wrap_content">
    
        <TextView android:id="@+id/tv" android:layout_width="match_parent" android:layout_height="36dp" android:layout_margin="8dp" android:background="@drawable/bg_channel" android:foreground="?attr/selectableItemBackground" android:layout_centerInParent="true" android:gravity="center"/>
    
        <ImageView android:id="@+id/img_edit" android:layout_alignParentRight="true" android:layout_width="16dp" android:visibility="invisible" android:layout_height="16dp"/>
    
    </RelativeLayout>

## activity\_demo.xml ##

<?xml version="1.0" encoding="utf-8"?>
    <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent">
    
        <android.support.v7.widget.RecyclerView android:id="@+id/recy" android:padding="8dp" android:clipChildren="false" android:clipToPadding="false" android:layout_width="match_parent" android:layout_height="match_parent"/>
    </FrameLayout>

## [新闻阅读器频道管理][Link 1] ##

[http_blog.csdn.net_tyk0910_article_details_51460808]: http://blog.csdn.net/tyk0910/article/details/51460808
[ItemTouchHelper]: /images/20220714/3dddb30ea8eb4bf9afe3597639ce6883.png
[http_www.jianshu.com_p_d30fd8da4eac]: http://www.jianshu.com/p/d30fd8da4eac
[ItemTouchHelper 1]: /images/20220714/986699daa7934373953dfda739ed3572.png
[Link 1]: http://blog.csdn.net/axi295309066/article/details/53353692