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今天就跟大家聊聊有关使用RecyclerView怎么实现一个拖拽排序效果，可能很多人都不太了解，为了让大家更加了解，小编给大家总结了以下内容，希望大家根据这篇文章可以有所收获。
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RecyclerView给我们提供了一个手势器：
ItemTouchHelper helper = new ItemTouchHelper(new ItemTouchHelper.Callback() {
@Override
public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
int dragFrlg = 0;
if (recyclerView.getLayoutManager() instanceof GridLayoutManager){
dragFrlg = ItemTouchHelper.UP|ItemTouchHelper.DOWN|ItemTouchHelper.LEFT|ItemTouchHelper.RIGHT;
}else if(recyclerView.getLayoutManager() instanceof LinearLayoutManager){
dragFrlg = ItemTouchHelper.UP|ItemTouchHelper.DOWN;
}
return makeMovementFlags(dragFrlg,0);
}
@Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
//滑动事件 下面注释的代码，滑动后数据和条目错乱，被舍弃
// Collections.swap(datas,viewHolder.getAdapterPosition(),target.getAdapterPosition());
// ap.notifyItemMoved(viewHolder.getAdapterPosition(),target.getAdapterPosition());
//得到当拖拽的viewHolder的Position
int fromPosition = viewHolder.getAdapterPosition();
//拿到当前拖拽到的item的viewHolder
int toPosition = target.getAdapterPosition();
if (fromPosition < toPosition) {
for (int i = fromPosition; i < toPosition; i++) {
Collections.swap(datas, i, i + 1);
}
} else {
for (int i = fromPosition; i > toPosition; i--) {
Collections.swap(datas, i, i - 1);
}
}
ap.notifyItemMoved(fromPosition, toPosition);
return true;
}
@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
//侧滑删除可以使用；
}
@Override
public boolean isLongPressDragEnabled() {
return true;
}
/**
* 长按选中Item的时候开始调用
* 长按高亮
* @param viewHolder
* @param actionState
*/
@Override
public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {
if (actionState != ItemTouchHelper.ACTION_STATE_IDLE) {
viewHolder.itemView.setBackgroundColor(Color.RED);
//获取系统震动服务//震动70毫秒
Vibrator vib = (Vibrator) getSystemService(Service.VIBRATOR_SERVICE);
vib.vibrate(70);
}
super.onSelectedChanged(viewHolder, actionState);
}
/**
* 手指松开的时候还原高亮
* @param recyclerView
* @param viewHolder
*/
@Override
public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
super.clearView(recyclerView, viewHolder);
viewHolder.itemView.setBackgroundColor(0);
ap.notifyDataSetChanged(); //完成拖动后刷新适配器，这样拖动后删除就不会错乱
}
});设置给RecyclerView即可：
helper.attachToRecyclerView(rv);
下面是完整的代码和Xml布局文件：
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private final String TAG = this.getClass().getSimpleName();
private List d = Arrays.asList(
"A","B","C","D","E","F","G"
,"H","I","J","K","L","M","N"
,"O","P","Q","R","S","T"
,"U","V","W","X","Y","Z");
private RecyclerView rv ;
private Ap ap;
private List datas;
private EditText edAdd;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initData();
rv = findViewById(R.id.rv);
edAdd =findViewById(R.id.et_add);
rv.setLayoutManager(new GridLayoutManager(this,3));
// rv.setLayoutManager(new LinearLayoutManager(this));
ap = new Ap(this, datas);
rv.setAdapter(ap);
helper.attachToRecyclerView(rv);
findViewById(R.id.tv).setOnClickListener(this);
findViewById(R.id.tv_add).setOnClickListener(this);
}
private void initData() {
datas = new ArrayList<>();
// 直接用d操作集合会崩溃，Arrays.asList集合不可增删改；详细可以看我的博客
for (int i = 0; i < d.size(); i++) {
datas.add(d.get(i));
}
}
@Override
public void onClick(View view) {
switch (view.getId()){
case R.id.tv:
for (int i = 0; i < datas.size(); i++) {
Log.i(TAG, "onClick: ____"+datas.get(i));
}
break;
case R.id.tv_add:
ap.add(edAdd.getText().toString().trim());
edAdd.setText(null);
break;
}
}
class Ap extends RecyclerView.Adapter{
private Context context;
public List stringList;
public Ap(Context context, List stringList) {
this.context = context;
this.stringList = stringList;
}
@Override
public Ap.Vh onCreateViewHolder(ViewGroup parent, int viewType) {
return new Vh(LayoutInflater.from(context).inflate(R.layout.item_rv,null));
}
@Override
public void onBindViewHolder(Ap.Vh holder, final int position) {
holder.tv.setText(stringList.get(position).toString());
holder.iv.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
remove(position);
}
});
}
@Override
public int getItemCount() {
return stringList.size();
}
public void add(T item){
int position = stringList.size();
stringList.add(item);
notifyItemInserted(position);
}
public void add(int position,T item){
stringList.add(position,item);
notifyItemInserted(position);
}
// public void remove(T item) {
// final int position = stringList.indexOf(item);
// if (-1 == position)
// return;
// stringList.remove(item);
// notifyItemRemoved(position);
// }
public void remove(int position) {
stringList.remove(position);
notifyItemRemoved(position);
notifyItemRangeChanged(position,stringList.size());
}
class Vh extends RecyclerView.ViewHolder {
public Vh(View itemView) {
super(itemView);
tv = itemView.findViewById(R.id.tv);
iv = itemView.findViewById(R.id.iv_delete);
}
public TextView tv;
public ImageView iv;
}
}
ItemTouchHelper helper = new ItemTouchHelper(new ItemTouchHelper.Callback() {
@Override
public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
int dragFrlg = 0;
if (recyclerView.getLayoutManager() instanceof GridLayoutManager){
dragFrlg = ItemTouchHelper.UP|ItemTouchHelper.DOWN|ItemTouchHelper.LEFT|ItemTouchHelper.RIGHT;
}else if(recyclerView.getLayoutManager() instanceof LinearLayoutManager){
dragFrlg = ItemTouchHelper.UP|ItemTouchHelper.DOWN;
}
return makeMovementFlags(dragFrlg,0);
}
@Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
//滑动事件 下面注释的代码，滑动后数据和条目错乱，被舍弃
// Collections.swap(datas,viewHolder.getAdapterPosition(),target.getAdapterPosition());
// ap.notifyItemMoved(viewHolder.getAdapterPosition(),target.getAdapterPosition());
//得到当拖拽的viewHolder的Position
int fromPosition = viewHolder.getAdapterPosition();
//拿到当前拖拽到的item的viewHolder
int toPosition = target.getAdapterPosition();
if (fromPosition < toPosition) {
for (int i = fromPosition; i < toPosition; i++) {
Collections.swap(datas, i, i + 1);
}
} else {
for (int i = fromPosition; i > toPosition; i--) {
Collections.swap(datas, i, i - 1);
}
}
ap.notifyItemMoved(fromPosition, toPosition);
return true;
}
@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
//侧滑删除可以使用；
}
@Override
public boolean isLongPressDragEnabled() {
return true;
}
/**
* 长按选中Item的时候开始调用
* 长按高亮
* @param viewHolder
* @param actionState
*/
@Override
public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {
if (actionState != ItemTouchHelper.ACTION_STATE_IDLE) {
viewHolder.itemView.setBackgroundColor(Color.RED);
//获取系统震动服务//震动70毫秒
Vibrator vib = (Vibrator) getSystemService(Service.VIBRATOR_SERVICE);
vib.vibrate(70);
}
super.onSelectedChanged(viewHolder, actionState);
}
/**
* 手指松开的时候还原高亮
* @param recyclerView
* @param viewHolder
*/
@Override
public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
super.clearView(recyclerView, viewHolder);
viewHolder.itemView.setBackgroundColor(0);
ap.notifyDataSetChanged(); //完成拖动后刷新适配器，这样拖动后删除就不会错乱
}
});
} Xml布局文件：