android RecyclerView_ZenDei技術網路在線

引用在項目的build.gradle添加依賴 RecyclierView使用的基本方法 recyclerView.setAdapter(); 添加適配器(必須) recyclerView.setLayoutManager(); 選擇一種佈局(必須) recyclerAdapter.setHeade ...

引用

在項目的build.gradle添加依賴

compile 'com.android.support:recyclerview-v7:23.4.0'

RecyclierView使用的基本方法

recyclerView.setAdapter(); 添加適配器(必須)

recyclerView.setLayoutManager(); 選擇一種佈局(必須)

recyclerAdapter.setHeaderView(); 添加頭佈局

recyclerAdapter.setFooterView(); 添加底部佈局

recyclerView.setItemAnimator(new DefaultItemAnimator()); 添加預設動畫

recyclerView.addItemDecoration(); 添加分割線

Layout Manager佈局管理器

1.三種佈局管理器：

new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false) 以垂直或者水平列表方式展示Item，第三個參數是否顛倒數據顯示

new GridLayoutManager(this,4) 以網格方式展示Item，第二個參數代表列數

new StaggeredGridLayoutManager(4, StaggeredGridLayoutManager.HORIZONTAL) 以瀑布流方式展示Item，第一個參數代表列數

2.常用方法

canScrollHorizontally();//能否橫向滾動
canScrollVertically();//能否縱向滾動
scrollToPosition(int position);//滾動到指定位置
setOrientation(int orientation);//設置滾動的方向
getOrientation();//獲取滾動方向
findViewByPosition(int position);//獲取指定位置的Item View
findFirstCompletelyVisibleItemPosition();//獲取第一個完全可見的Item位置
findFirstVisibleItemPosition();//獲取第一個可見Item的位置
findLastCompletelyVisibleItemPosition();//獲取最後一個完全可見的Item位置
findLastVisibleItemPosition();//獲取最後一個可見Item的位置

Adapter適配器模板

RecyclerView必須自定義適配器，並且自己創建事件監聽，佈局和數據的綁定順序，每個Item都會執行一遍：getIItemViewType(綁定類型) > onCreateViewHolder(選擇佈局類型) > onBindViewHolder(綁定數據)

notifyItemInserted(position);插入一個item

notifyItemRemoved(position); 移除一個item

notifyItemChanged(position) 刷新item

public class DataRecyclerAdapter extends RecyclerView.Adapter<DataRecyclerAdapter.MyViewHolder>{
    private List<String> list;
    private Context context;
    private List<Integer> mHeights;
    private static int TYPE_TITLE=0;
    private static int TYPE_FOOTER=1;
    private static int TYPE_CONTENT =2;
    private View mHeaderView;
    private View mFooterView;

    public DataRecyclerAdapter(Context context, List<String> list) {
        this.list=list;
        mHeights = new ArrayList<>();
        this.context=context;
    }

    //根據不同的類型適應不用的佈局
    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        if(mHeaderView != null && viewType == TYPE_TITLE) {
            return new MyViewHolder(mHeaderView);
        }
        if(mFooterView != null && viewType == TYPE_FOOTER) {
            return new MyViewHolder(mFooterView);
        }
        return new MyViewHolder(LayoutInflater.from(context).inflate(R.layout.options_item3,parent,false));
    }

    //給item分佈不同的類型
    @Override
    public int getItemViewType(int position) {
        if (position == 0){
            return TYPE_TITLE;
         }else if(position==list.size()){
            return TYPE_FOOTER;
        }else{
            return TYPE_CONTENT;
        }
    }

    public View getHeaderView() {
        return mHeaderView;
    }
    //添加自定義的頭部
    public void setHeaderView(View headerView) {
        mHeaderView = headerView;
        notifyItemInserted(0);
    }

    public View getFooterView() {
        return mFooterView;
    }
    //添加自定義底部
    public void setFooterView(View footerView) {
        mFooterView = footerView;
        notifyItemInserted(list.size()+1);
    }
    //主體佈局
    @Override
    public void onBindViewHolder(final MyViewHolder holder, int position) {
        if(getItemViewType(position) != TYPE_CONTENT) {
            return;
        }
            holder.textView.setText(list.get(position-1));

        if (mOnItemClickLitener != null){
            holder.itemView.setOnClickListener(new View.OnClickListener(){
                @Override
                public void onClick(View v){
                    int pos = holder.getLayoutPosition();
                    mOnItemClickLitener.onItemClick(holder.itemView, pos);
                }
            });

            holder.itemView.setOnLongClickListener(new View.OnLongClickListener(){
                @Override
                public boolean onLongClick(View v){
                    int pos = holder.getLayoutPosition();
                    mOnItemClickLitener.onItemLongClick(holder.itemView, pos);
                    return true;
                }
            });
        }
    }

    //獲取item總數
    @Override
    public int getItemCount() {
         if(mFooterView !=null){
            return list.size()+1;
        }else {
            return list.size();
        }
    }
    //監聽器介面
    public interface OnItemClickLitener{
        void onItemClick(View view, int position);
        void onItemLongClick(View view , int position);
    }

    private OnItemClickLitener mOnItemClickLitener;

    public void setOnMyItemClickLitener(OnItemClickLitener mOnItemClickLitener) {
        this.mOnItemClickLitener = mOnItemClickLitener;
    }

   //頭和底部的佈局
    class MyViewHolder extends RecyclerView.ViewHolder {
        private TextView textView;
        MyViewHolder(View itemView) {
            super(itemView);
            if (itemView == mHeaderView||itemView == mFooterView){
                return;
            }
            textView= (TextView) itemView.findViewById(R.id.options_tv);
            textView.setText("UUU");
        }
    }
    //模擬新增的數據
    public void addData(int position) {
        list.add(position, "Insert 數據");
        notifyItemInserted(position+1);
        Toast.makeText(context,""+list.size(),Toast.LENGTH_SHORT).show();
    }
    //移除一個佈局
    public void removeData(int position) {
        list.remove(position);
        notifyItemRemoved(position);
    }

實例

private void initDataRecyclerAdapter(){
    recyclerAdapter=new DataRecyclerAdapter(this,mData);
    //佈局管理器
    recyclerView.setLayoutManager( new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false));
    //分割線
    recyclerView.addItemDecoration(new DividerItemDecoration(this,
            DividerItemDecoration.HORIZONTAL));
    //使用預設動畫
    recyclerView.setItemAnimator(new DefaultItemAnimator());
    //不使用預設的佈局類型，添加自定義頭部佈局
    recyclerAdapter.setHeaderView(LayoutInflater.from(this).inflate(R.layout.options_title, recyclerView, false));
    //不使用預設的佈局類型，添加自定義底部佈局
    LayoutInflater inflater= LayoutInflater.from(this);
    View footerView = inflater.inflate(R.layout.options_footer, null);
    recyclerAdapter.setFooterView(footerView);
    //底部佈局事件，增加一個item
    footerView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Toast.makeText(MainActivity.this,"展開",Toast.LENGTH_SHORT).show();
            recyclerAdapter.addData(mData.size());
        }
    });
    recyclerView.setAdapter(recyclerAdapter);
    recyclerAdapter.setOnMyItemClickLitener(new DataRecyclerAdapter.OnItemClickLitener() {
        //item的點擊事件，移除一個item
        @Override
        public void onItemClick(View view, int position) {
            recyclerAdapter.removeData(position);
            Toast.makeText(MainActivity.this,""+mData.size(),Toast.LENGTH_SHORT).show();
        }
        //item的長按事件，顯示item下標
        @Override
        public void onItemLongClick(View view, int position) {
            Toast.makeText(MainActivity.this,"第"+position+"個",Toast.LENGTH_SHORT).show();
        }
    });
}
//模擬數據源
private void addData(){
    mData= new ArrayList<>();
    for (int i=1;i<20;i++) {
        mData.add("數據"+i+"個");
    }
}

ItemTouchHelper滑動拖拽

1.getMovementFlags

用於設置是否處理拖拽事件和滑動事件，如果是列表類型的，拖拽只有ItemTouchHelper.UP、ItemTouchHelper.DOWN兩個方向
如果是網格類型的，拖拽則有UP、DOWN、LEFT、RIGHT四個方向
最後，需要調用return makeMovementFlags(dragFlags, swipeFlags);將設置的標誌位return回去

   @Override
    public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
        if (recyclerView.getLayoutManager() instanceof GridLayoutManager) {
            final int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN | ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT;
           //網格佈局不處理滑動事件
            final int swipeFlags = 0;
        } else {
            final int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;
            //列表佈局不處理滑動事件
            final int swipeFlags = 0; 
        }
        return makeMovementFlags(dragFlags, swipeFlags);
    }

2.onMove

長按item的時候就會進入拖拽,併在拖拽過程中不斷回調
viewHolder.getAdapterPosition(); 得到拖動ViewHolder的position
target.getAdapterPosition(); 得到目標ViewHolder的position

@Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
    int fromPosition = viewHolder.getAdapterPosition();
    int toPosition = target.getAdapterPosition();
    if (fromPosition < toPosition) {
        //分別把中間所有的item的位置重新交換
        for (int i = fromPosition; i < toPosition; i++) {
            Collections.swap(mData, i, i + 1);
        }
    } else {
        for (int i = fromPosition; i > toPosition; i--) {
            Collections.swap(mData, i, i - 1);
        }
    }
    //執行移動操作
    recyclerAdapter.notifyItemMoved(fromPosition, toPosition);
    return true;
}

3.onSwiped

移動item的時候就會進入滑動併在滑動過程中不斷回調
viewHolder.getAdapterPosition();//得到拖動ViewHolder的position
target.getAdapterPosition();//得到目標ViewHolder的position

@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
    int position = viewHolder.getAdapterPosition();
    //執行移除操作
    mData.remove(position);
    recyclerAdapter.notifyItemRemoved(position);
}

4.onChildDraw

滑動時會不斷回調，返回X、Y的坐標

@Override
public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
    super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
    if(actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
        //滑動時改變Item的透明度
        final float alpha = 1 - Math.abs(dX) / (float)viewHolder.itemView.getWidth();
        viewHolder.itemView.setAlpha(alpha);
        viewHolder.itemView.setTranslationX(dX);
    }
}

5.onSelectedChanged

當選中Item時候會調用該方法

 @Override
    public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {
            //選中item開始拖拽時，改變顏色
            viewHolder.itemView.setBackgroundColor(Color.blue);
        
    }

6.clearView

item被放開或者動畫完成的回調

 @Override
 public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
     super.clearView(recyclerView, viewHolder);
     //拖拽或滑動完成時，變回白色
     viewHolder.itemView.setBackgroundColor(0);
 }

7.isLongPressDragEnabled

是否支持拖拽操作，預設是支持返回true。如果想指定item可以拖拽，需要重寫返回false，在item的長按監聽事件里調用startDrag(ViewHolder)開啟拖拽

 @Override
 public boolean isLongPressDragEnabled() {
   return true;
 }

8.isItemViewSwipeEnabled

是否支持滑動操作，預設是支持返回true。如果想指定item可以滑動，需要重寫返回false，在item的點擊事件里調用startSwipe(ViewHolder)開啟滑動。

@Override
public boolean isItemViewSwipeEnabled() {
    return true;
}

9.實例

ItemTouchHelper.Callback mCallback2 = new ItemTouchHelper.SimpleCallback(ItemTouchHelper.UP|ItemTouchHelper.DOWN,ItemTouchHelper.RIGHT) {
   
    @Override
    public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
        int fromPosition = viewHolder.getAdapterPosition();
        int toPosition = target.getAdapterPosition();
        if (fromPosition < toPosition) {
            //分別把中間所有的item的位置重新交換
            for (int i = fromPosition; i < toPosition; i++) {
                Collections.swap(mData, i, i + 1);
            }
        } else {
            for (int i = fromPosition; i > toPosition; i--) {
                Collections.swap(mData, i, i - 1);
            }
        }
        recyclerAdapter.notifyItemMoved(fromPosition, toPosition);
        return true;
    }

    @Override
    public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
        int position = viewHolder.getAdapterPosition();
        mData.remove(position);
        recyclerAdapter.notifyItemRemoved(position);
    }

    @Override
    public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
        super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
        if(actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
            //滑動時改變Item的透明度
            final float alpha = 1 - Math.abs(dX) / (float)viewHolder.itemView.getWidth();
            viewHolder.itemView.setAlpha(alpha);
            viewHolder.itemView.setTranslationX(dX);
        }
    }

    @Override
    public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {
        super.onSelectedChanged(viewHolder, actionState);

    }

    @Override
    public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
        super.clearView(recyclerView, viewHolder);
        viewHolder.itemView.setBackgroundColor(0);
    }
};

//添加ItemTouchHelper介面
ItemTouchHelper itemTouchHelper = new ItemTouchHelper(mCallback);

//指定RecyclerView
itemTouchHelper.attachToRecyclerView(recyclerView);