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。