Android使用ItemTouchHelper实现侧滑删除和拖拽

本文实例为大家分享了如何使用ItemTouchHelper实现侧滑删除和拖拽的具体代码，供大家参考，具体内容如下

1. 定义一个简单bean类:

public class ImgText {
 public int resId;
 public String des;
}

2. 实现一个RecyclerView.Adapter

public class SwipeRecyclerAdapter extends RecyclerView.Adapter<SwipeRecyclerAdapter.MyHolder> {

private List<ImgText> mList;

public SwipeRecyclerAdapter(List<ImgText> list) {
   mList = list;
 }

@Override
 public MyHolder onCreateViewHolder(ViewGroup parent, int viewType) {

View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_swipe_recycler, parent, false);
   return new MyHolder(view);
 }

@Override
 public void onBindViewHolder(MyHolder holder, int position) {
   ImgText imgText = mList.get(position);
   holder.img.setImageResource(imgText.resId);
   holder.des.setText(imgText.des);
 }

@Override
 public int getItemCount() {
   return mList.size();
 }

public class MyHolder extends RecyclerView.ViewHolder {

private ImageView img;
   private TextView des;

public MyHolder(View itemView) {
     super(itemView);
     img = (ImageView) itemView.findViewById(R.id.img);
     des = (TextView) itemView.findViewById(R.id.text);
   }
 }
}

3.绘制分割线:

public class DividerItemDecoration extends RecyclerView.ItemDecoration {
 private static final int[] ATTRS = new int[]{android.R.attr.listDivider};
 public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;
 public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;
 private Drawable mDivider;
 private int mOrientation;
 public DividerItemDecoration(Context context, int orientation) {
   final TypedArray a = context.obtainStyledAttributes(ATTRS);
   mDivider = a.getDrawable(0);
   a.recycle();
   setOrientation(orientation);
 }
 public void setOrientation(int orientation) {
   if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST) {
     throw new IllegalArgumentException("invalid orientation");
   }
   mOrientation = orientation;
 }
 @Override
 public void onDraw(Canvas c, RecyclerView parent) {
   if (mOrientation == VERTICAL_LIST) {
     drawVertical(c, parent);
   } else {
     drawHorizontal(c, parent);
   }
 }
 public void drawVertical(Canvas c, RecyclerView parent) {
   final int left = parent.getPaddingLeft();
   final int right = parent.getWidth() - parent.getPaddingRight();
   final int childCount = parent.getChildCount();
   for (int i = 0; i < childCount; i++) {
     final View child = parent.getChildAt(i);
     RecyclerView v = new RecyclerView(
         parent.getContext());
     final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
         .getLayoutParams();
     final int top = child.getBottom() + params.bottomMargin;
     final int bottom = top + mDivider.getIntrinsicHeight();
     mDivider.setBounds(left, top, right, bottom);
     mDivider.draw(c);
   }
 }
 public void drawHorizontal(Canvas c, RecyclerView parent) {
   final int top = parent.getPaddingTop();
   final int bottom = parent.getHeight() - parent.getPaddingBottom();

final int childCount = parent.getChildCount();
   for (int i = 0; i < childCount; i++) {
     final View child = parent.getChildAt(i);
     final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
         .getLayoutParams();
     final int left = child.getRight() + params.rightMargin;
     final int right = left + mDivider.getIntrinsicHeight();
     mDivider.setBounds(left, top, right, bottom);
     mDivider.draw(c);
   }
 }
 @Override
 public void getItemOffsets(Rect outRect, int itemPosition,
               RecyclerView parent) {
   if (mOrientation == VERTICAL_LIST) {
     outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
   } else {
     outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
   }
 }
}

4. 实现ItemTouchHelper.Callback接口:

public class SwipeCallback<T> extends ItemTouchHelper.Callback {

private RecyclerView.Adapter<? extends RecyclerView.ViewHolder> mAdapter;
 private List<T> mList;

public SwipeCallback(RecyclerView.Adapter adapter, List<T> list) {
   mAdapter = adapter;
   mList = list;
 }

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

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

@Override
 public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
   int dragFlag=ItemTouchHelper.UP|ItemTouchHelper.DOWN;
   int swipeFlags=ItemTouchHelper.END|ItemTouchHelper.START;

return makeMovementFlags(dragFlag,swipeFlags);
 }

//用于移动item的位置
 @Override
 public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
   Collections.swap(mList, viewHolder.getAdapterPosition(), target.getAdapterPosition());
   mAdapter.notifyItemMoved(viewHolder.getAdapterPosition(), target.getAdapterPosition());

return true;
 }

//一般用于滑动删除
 @Override
 public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
   mList.remove(viewHolder.getAdapterPosition());
   mAdapter.notifyItemRemoved(viewHolder.getAdapterPosition());
 }
}

5.编写侧滑删除和拖拽Activity

public class SwipeRecyclerViewActivity extends AppCompatActivity {
 private RecyclerView mRecyclerView;

private List<ImgText> mList;

@Override
 protected void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   setContentView(R.layout.activity_swipe_recycler);
   mRecyclerView= (RecyclerView) findViewById(R.id.recycler);
   mList=new ArrayList<>();

for (int i = 0; i < 20; i++) {
     ImgText it= new ImgText();
     it.resId=R.mipmap.ic_launcher;
     it.des=i+"侧滑删除文字";
     mList.add(it);
   }

final SwipeRecyclerAdapter adapter= new SwipeRecyclerAdapter(mList);
   RecyclerView.LayoutManager manager= new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false);
   mRecyclerView.setLayoutManager(manager);
   mRecyclerView.setItemAnimator(new DefaultItemAnimator());
   mRecyclerView.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL_LIST));
   mRecyclerView.setAdapter(adapter);
   ItemTouchHelper swipeItemHelper= new ItemTouchHelper(new SwipeCallback<>(adapter,mList));
   swipeItemHelper.attachToRecyclerView(mRecyclerView);
 }
}

来源：https://blog.csdn.net/showdy/article/details/51578150