RecyclerView 實現側滑刪除和拖動排序
在使用ListView的時候實現拖動排序，主要靠繼承別人第三方的，在網上有很多例子，
這裡不介紹，主要是介紹一下recycleview的拖動排序和滑動刪除
一、主要知識點：
1、 ItemTouchHelper.Callback的使用
2、介面傳值
ItemTouchHelper.Callback
getMovementFlags：回撥監聽時先呼叫的，用來判斷當前是什麼動作，比如判斷方向
isLongPressDragEnabled 是否允許長按拖拽效果
onMove 當移動的時候回撥的方法 拖拽
onSelectedChanged 當前選中的條目拖拽或滑動時執行
clearView 當用戶與itemview互動完且動畫執行完，呼叫
onSwiped 側滑的時候回撥
onChildDraw 在RecyclerView呼叫onDraw方法的時候，呼叫此方法
二、流程
1、建立adapter繫結在RecyclerView上
2、給RecyclerView繫結ItemTouchHelper
ItemTouchHelper itemTouchHelper = new ItemTouchHelper(new ItemTouchHelperCallback(myAdapter));
itemTouchHelper.attachToRecyclerView(recyclerView);
3、在構造ItemTouchHelper物件時候，需要實現它的Callback，可以直接建立，也可以建立Class實現
4、繫結startDrag方法
5、然後再ItemTouchHelper.Callback完成相應的操作
三、以下是程式碼：
建立一個這樣的item代
<?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="wrap_content"
android:orientation="vertical">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="80dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
<ImageView
android:id="@+id/item_test_imageview_icon"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:src="@mipmap/logo_1" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center_vertical"
android:orientation="vertical">
<TextView
android:id="@+id/item_test_textView_name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="我是測試"
android:textColor="#000000"
android:textSize="16sp" />
<TextView
android:id="@+id/item_test_textView_descirption"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:text="我是測試"
android:textColor="#858585"
android:textSize="14sp" />
</LinearLayout>
</LinearLayout>
<TextView
android:layout_width="100dp"
android:layout_height="80dp"
android:layout_alignParentRight="true"
android:background="#f33213"
android:gravity="center"
android:text="刪除"
android:textColor="#ffffff"
android:textSize="16sp"
android:visibility="gone" />
</RelativeLayout>
<TextView
android:layout_width="match_parent"
android:layout_height="1px"
android:background="#585858" />
</LinearLayout>
建立ItemTouchHelperCallback類 public class ItemTouchHelperCallback extends ItemTouchHelper.Callback {private ItemTouchMoveListener moveListener;
public ItemTouchHelperCallback(ItemTouchMoveListener moveListener) {
this.moveListener = moveListener;
}
//Callback 回撥監聽時先呼叫的，用來判斷當前是什麼動作，比如判斷方向
@Override
public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
//up down ，left，right
//拖拽方向是那兩個
int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;
//0不監聽，側滑方向
int swipeFlags = ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT;
int flags = makeMovementFlags(dragFlags, swipeFlags);
return flags;
}
@Override
public boolean isLongPressDragEnabled() {
//是否允許長按拖拽效果
return super.isLongPressDragEnabled();
}
//當移動的時候回撥的方法 拖拽
@Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
if (viewHolder.getItemViewType() != target.getItemViewType()) {
return false;
}
//拖拽時，不斷地呼叫adapter.notifyItemMoved(from,to)
return moveListener.onItemMove(viewHolder.getAdapterPosition(), target.getAdapterPosition());
}
@Override
public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {
if (actionState != ItemTouchHelper.ACTION_STATE_IDLE) {
viewHolder.itemView.setBackgroundColor(viewHolder.itemView.getContext().getResources().getColor(R.color.colorPrimary));
}
super.onSelectedChanged(viewHolder, actionState);
}
@Override
public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
//恢復
viewHolder.itemView.setBackgroundColor(Color.WHITE);
// viewHolder.itemView.setAlpha(1);//1~0
// viewHolder.itemView.setScaleX(1);
// viewHolder.itemView.setScaleY(1);
super.clearView(recyclerView, viewHolder);
}
//側滑的時候回撥
@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
//側滑監聽，呼叫notifyItemRemoved(position)
moveListener.onItemRemove(viewHolder.getAdapterPosition());
}
@Override
public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
//dX水平方向移動的增量（負，左。正，右）0-view,getWidth
float alpha=1-Math.abs(dX)/viewHolder.itemView.getWidth();
if(actionState==ItemTouchHelper.ACTION_STATE_SWIPE){
//透明度變化
viewHolder.itemView.setAlpha(alpha);//1~0
viewHolder.itemView.setScaleX(alpha);
viewHolder.itemView.setScaleY(alpha);
}
if(alpha==0){
viewHolder.itemView.setAlpha(1);//1~0
viewHolder.itemView.setScaleX(1);
viewHolder.itemView.setScaleY(1);
}
super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
}
}
public class MyAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> implements ItemTouchMoveListener {
private List<MessageEntity> list;
private StartDragInterface dragInterface;
public MyAdapter(List<MessageEntity> list, StartDragInterface dragInterface) {
this.list = list;
this.dragInterface = dragInterface;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
return new MyViewHolder(LayoutInflater.from(parent.getContext()).inflate(R.layout.item_test, parent, false));
}
@Override
public void onBindViewHolder(final RecyclerView.ViewHolder holder, int position) {
if (holder instanceof MyViewHolder) {
((MyViewHolder) holder).textView_name.setText(list.get(position).getName());
((MyViewHolder) holder).text_description.setText(list.get(position).getDescription());
((MyViewHolder) holder).imageView.setImageResource(list.get(position).getIcon());
((MyViewHolder) holder).imageView.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
//按下
if (dragInterface != null) {
dragInterface.onStartDrag(holder);
}
}
return false;
}
});
}
}
@Override
public int getItemCount() {
return list.size();
}
@Override
public boolean onItemMove(int formPosition, int toPosition) {
Collections.swap(list, formPosition, toPosition);
notifyItemMoved(formPosition, toPosition);
return true;
}
@Override
public boolean onItemRemove(int position) {
list.remove(position);
notifyItemRemoved(position);
return true;
}
private class MyViewHolder extends RecyclerView.ViewHolder {
public ImageView imageView;
public TextView textView_name, text_description;
public MyViewHolder(View itemView) {
super(itemView);
imageView = (ImageView) itemView.findViewById(R.id.item_test_imageview_icon);
textView_name = (TextView) itemView.findViewById(R.id.item_test_textView_name);
text_description = (TextView) itemView.findViewById(R.id.item_test_textView_descirption);
}
}
public interface ItemTouchMoveListener {
boolean onItemMove(int formPosition, int toPosition);
boolean onItemRemove(int position);
}
public interface StartDragInterface {
void onStartDrag(RecyclerView.ViewHolder viewHolder);
}
public class MessageEntity {
private int icon;
private String name;
private String description;
public MessageEntity(int icon, String name, String description) {
this.icon = icon;
this.name = name;
this.description = description;
}
public int getIcon() {
return icon;
}
public void setIcon(int icon) {
this.icon = icon;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
}
public class MainActivity extends AppCompatActivity implements StartDragInterface {
private RecyclerView recyclerView;
private MyAdapter myAdapter;
private List<MessageEntity> listData = new ArrayList<>();
private ItemTouchHelper itemTouchHelper;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
recyclerView = (RecyclerView) findViewById(R.id.activity_main_recyclerView);
initData();
myAdapter = new MyAdapter(listData,this);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
recyclerView.setAdapter(myAdapter);
//條目觸控幫助類
itemTouchHelper = new ItemTouchHelper(new ItemTouchHelperCallback(myAdapter));
itemTouchHelper.attachToRecyclerView(recyclerView);
// itemTouchHelper.startDrag();
// itemTouchHelper.startSwipe();
}
@Override
public void onStartDrag(RecyclerView.ViewHolder viewHolder) {
itemTouchHelper.startDrag(viewHolder);
}
private void initData() {
for (int i = 0; i < 20; i++) {
MessageEntity entity = new MessageEntity(R.mipmap.logo_1, "Test" + i, "我是描述我是描述" + i);
listData.add(entity);
}
}
程式碼在我的資源中可以免費下載