Android recyclerview实现拖拽排序和侧滑删除
Recyclerview现在基本已经替代Listview了，RecyclerView也越来越好用了 当我们有实现条目的拖拽排序和侧滑删除时 可以直接时候Recyclerview提供的API就可以直接实现了
先贴上主要代码
privatevoidinitveiw(){
ArrayList<String>items=newArrayList<>(Arrays.asList("itme1","item2","itme3","item4","item5","item6","item7","item8","itme9","item10","itme11","item12","item13","item14","item15","item16"));
recyclerView.setLayoutManager(newLinearLayoutManager(this,LinearLayoutManager.VERTICAL,false));
SimpleAdapteradapter=newSimpleAdapter(items);
recyclerView.setAdapter(adapter);
ItemTouchHelperhelper=newItemTouchHelper(newMyItemTouchCallback(adapter));
helper.attachToRecyclerView(recyclerView);
}
publicclassMyItemTouchCallbackextendsItemTouchHelper.Callback{
privateSimpleAdapteradapter;
publicMyItemTouchCallback(SimpleAdapteradapter){
this.adapter=adapter;
}
@Override
publicintgetMovementFlags(RecyclerViewrecyclerView,RecyclerView.ViewHolderviewHolder){
intdragFlag;
intswipeFlag;
RecyclerView.LayoutManagermanager=recyclerView.getLayoutManager();
if(managerinstanceofGridLayoutManager){
dragFlag=ItemTouchHelper.DOWN|ItemTouchHelper.UP|ItemTouchHelper.LEFT|ItemTouchHelper.RIGHT;
swipeFlag=0;
}else{
dragFlag=ItemTouchHelper.DOWN|ItemTouchHelper.UP;
swipeFlag=ItemTouchHelper.END|ItemTouchHelper.START;
}
returnmakeMovementFlags(dragFlag,swipeFlag);
}
@Override
publicbooleanonMove(RecyclerViewrecyclerView,RecyclerView.ViewHolderviewHolder,RecyclerView.ViewHoldertarget){
intfromPosition=viewHolder.getAdapterPosition();
inttoPosition=target.getAdapterPosition();
if(fromPosition<toPosition){
for(inti=fromPosition;i<toPosition;i++){
Collections.swap(adapter.getDataList(),i,i+1);
}
}else{
for(inti=fromPosition;i>toPosition;i--){
Collections.swap(adapter.getDataList(),i,i-1);
}
}
recyclerView.getAdapter().notifyItemMoved(fromPosition,toPosition);
returntrue;
}
@Override
publicvoidonSwiped(RecyclerView.ViewHolderviewHolder,intdirection){
intposition=viewHolder.getAdapterPosition();
if(direction==ItemTouchHelper.END|direction==ItemTouchHelper.START){
adapter.getDataList().remove(position);
adapter.notifyItemRemoved(position);
}
}
@Override
publicvoidonSelectedChanged(RecyclerView.ViewHolderviewHolder,intactionState){
super.onSelectedChanged(viewHolder,actionState);
if(actionState==ItemTouchHelper.ACTION_STATE_DRAG){
viewHolder.itemView.setBackgroundColor(Color.BLUE);
}
}
@Override
publicvoidclearView(RecyclerViewrecyclerView,RecyclerView.ViewHolderviewHolder){
super.clearView(recyclerView,viewHolder);
viewHolder.itemView.setBackgroundColor(0);
}
}
步骤：
创建ItemTouchHelper对象时候，需要我们传入一个实现了ItemTouchHelper.Callback接口的对象。而排序和删除的逻辑都封装在了这个ItemTouchHelper.Callback的对象里面了。
privatevoidinitveiw(){
ArrayList<String>items=newArrayList<>(Arrays.asList("itme1","item2","itme3","item4","item5","item6","item7","item8","itme9","item10","itme11","item12","item13","item14","item15","item16"));
recyclerView.setLayoutManager(newLinearLayoutManager(this,LinearLayoutManager.VERTICAL,false));
SimpleAdapteradapter=newSimpleAdapter(items);
recyclerView.setAdapter(adapter);
ItemTouchHelperhelper=newItemTouchHelper(newMyItemTouchCallback(adapter));
helper.attachToRecyclerView(recyclerView);
}
实现ItemTouchHelper.Callback接口后有三个方法需要重写：
getMovementFlags(RecyclerViewrecyclerView,RecyclerView.ViewHolderviewHolder)：设置滑动类型的标记。需要设置两种类型的flag，即dragFlags和swipeFlags，分别代表着拖拽标记和滑动标记。最后需要调用makeMovementFlags(dragFlags,
swipeFlags)方法来合成返回。
onMove(RecyclerViewrecyclerView,RecyclerView.ViewHolderviewHolder,RecyclerView.ViewHoldertarget)：当用户拖拽列表某个item时会回调。很明显，拖拽排序的代码应该在这个方法中实现。
onSwiped(RecyclerView.ViewHolderviewHolder,intdirection)：当用户滑动列表某个item时会回调。所以侧滑删除的代码应该在这个方法中实现。
下面是重写的几个方法：
第一个，getMovementFlags方法
@Override
publicintgetMovementFlags(RecyclerViewrecyclerView,RecyclerView.ViewHolderviewHolder){
intdragFlag;
intswipeFlag;
RecyclerView.LayoutManagermanager=recyclerView.getLayoutManager();
if(managerinstanceofGridLayoutManager){
dragFlag=ItemTouchHelper.DOWN|ItemTouchHelper.UP|ItemTouchHelper.LEFT|ItemTouchHelper.RIGHT;
swipeFlag=0;
}else{
dragFlag=ItemTouchHelper.DOWN|ItemTouchHelper.UP;
swipeFlag=ItemTouchHelper.END|ItemTouchHelper.START;
}
returnmakeMovementFlags(dragFlag,swipeFlag);
}
这个方法里面根据LayoutManager分了两种情况，根据自己的情况去分
在GridLayoutManager中只能上下左右拖拽但是不能侧滑删除，所以swipFlag=0；swipeFlag的值ItemTouchHelper.END是右滑删除，ItemTouchHelper.START是左滑删除
最后调用makeMovementFlags方法合成返回
第二个，onMove方法
@Override
publicbooleanonMove(RecyclerViewrecyclerView,RecyclerView.ViewHolderviewHolder,RecyclerView.ViewHoldertarget){
intfromPosition=viewHolder.getAdapterPosition();
inttoPosition=target.getAdapterPosition();
if(fromPosition<toPosition){
for(inti=fromPosition;i<toPosition;i++){
Collections.swap(adapter.getDataList(),i,i+1);
}
}else{
for(inti=fromPosition;i>toPosition;i--){
Collections.swap(adapter.getDataList(),i,i-1);
}
}
recyclerView.getAdapter().notifyItemMoved(fromPosition,toPosition);
returntrue;
}
这个方法是用户在拖拽item的时候调用。所以关于列表排序的代码应该写在这里。方法参数中的viewHolder代表的是用户当前拖拽的item，而target代表的是被用户拖拽所覆盖的那个item。所以在onMove(RecyclerViewrecyclerView,RecyclerView.ViewHolderviewHolder,RecyclerView.ViewHoldertarget)方法中的逻辑就是把fromPosition至toPosition为止改变它们的位置。
第三个，onSwiped方法
@Override
publicvoidonSwiped(RecyclerView.ViewHolderviewHolder,intdirection){
intposition=viewHolder.getAdapterPosition();
if(direction==ItemTouchHelper.END|direction==ItemTouchHelper.START){
adapter.getDataList().remove(position);
adapter.notifyItemRemoved(position);
}
}
这个方法是在用户侧滑的时候调用的，在里面对adapter的数据进行删除就可以了
最后两个方法
@Override
publicvoidonSelectedChanged(RecyclerView.ViewHolderviewHolder,intactionState){
super.onSelectedChanged(viewHolder,actionState);
if(actionState==ItemTouchHelper.ACTION_STATE_DRAG){
viewHolder.itemView.setBackgroundColor(Color.BLUE);
}
}
@Override
publicvoidclearView(RecyclerViewrecyclerView,RecyclerView.ViewHolderviewHolder){
super.clearView(recyclerView,viewHolder);
viewHolder.itemView.setBackgroundColor(0);
}
}
就是优化的方法，第一个是选择条目改变状态，第二个是手指抬起之后恢复条目状态
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持毛票票。