Android实现RecyclerView侧滑删除和长按拖拽-ItemTouchHelper

转:http://blog.csdn.net/kaifa1321/article/details/51817621http://blog.csdn.net/u010687392/article/details/47950199list_item.xml
<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:background="#F9F9F9"    android:layout_height="40dp">    <TextView        android:id="@+id/iv_item"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_centerVertical="true"        android:gravity="center" />    <ImageView        android:layout_width="match_parent"        android:layout_height="1dp"        android:layout_alignParentBottom="true"        android:background="#88888888" /></RelativeLayout>
adapter
package example.com.itemtouchhelper;import android.content.Context;import android.support.v7.widget.RecyclerView;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.TextView;import java.util.List;/** * Created by Administrator on 2016/12/6. */public class ListAdapter extends RecyclerView.Adapter<ListAdapter.ViewHolder> {    private Context context;    private List<String> datas;    private final LayoutInflater mInflater;    public ListAdapter(Context context, List<String> datas) {        this.context = context;        this.datas = datas;        mInflater = LayoutInflater.from(context);    }    @Override    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {        return new ViewHolder(mInflater.inflate(R.layout.list_item, parent, false));    }    @Override    public void onBindViewHolder(ViewHolder holder, int position) {        System.out.println("======="+position);        holder.iv_item.setText(datas.get(position));    }    @Override    public int getItemCount() {        return datas.size();    }    public static class ViewHolder extends RecyclerView.ViewHolder {        private TextView iv_item;        public ViewHolder(View itemView) {            super(itemView);            iv_item = (TextView) itemView.findViewById(R.id.iv_item);        }    }}

mainActivity
//1.设置适配器        LinearLayoutManager layoutManager = new LinearLayoutManager(this);        final ListAdapter adapter = new ListAdapter(this, datas);        recyclerView.setLayoutManager(layoutManager);        recyclerView.setAdapter(adapter);        //2.设置ItemTouchHelper        //0则不执行拖动或者滑动        ItemTouchHelper.SimpleCallback mCallback = new ItemTouchHelper.SimpleCallback(ItemTouchHelper.UP | ItemTouchHelper.DOWN, ItemTouchHelper.RIGHT | ItemTouchHelper.LEFT) {            @Override            public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {                int fromPosition = viewHolder.getAdapterPosition();                int toPosition = target.getAdapterPosition();                if (fromPosition < toPosition) {                    //分别把中间所有的item的位置重新交换                    for (int i = fromPosition; i < toPosition; i++) {                        Collections.swap(datas, i, i + 1);                    }                } else {                    //分别把中间所有的item的位置重新交换                    for (int i = fromPosition; i > toPosition; i--) {                        Collections.swap(datas, i, i - 1);                    }                }                adapter.notifyItemMoved(fromPosition, toPosition);                //返回true表示执行拖动                return true;            }            @Override            public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {                final int position = viewHolder.getAdapterPosition();                new AlertDialog.Builder(MainActivity.this)                        .setCancelable(false)                        .setMessage("你确定删除该项吗？")                        .setNegativeButton("取消", new DialogInterface.OnClickListener() {                            @Override                            public void onClick(DialogInterface dialogInterface, int i) {                                adapter.notifyDataSetChanged();                            }                        })                        .setPositiveButton("确定", new DialogInterface.OnClickListener() {                            @Override                            public void onClick(DialogInterface dialogInterface, int i) {                                datas.remove(position);                                adapter.notifyDataSetChanged();                                Toast.makeText(MainActivity.this, "删除" + position, Toast.LENGTH_SHORT).show();                            }                        }).show();            }            @Override            public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {                super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);                final float alpha = 1 - Math.abs(dX) / (float) viewHolder.itemView.getWidth();                if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {                    //滑动时改变Item的透明度                    viewHolder.itemView.setAlpha(alpha);                    viewHolder.itemView.setTranslationX(dX);                }                //防止item复用出现问题，如果大家不理解下面这段代码，可以自行注释效果，                if (alpha <= 0) {                    viewHolder.itemView.setAlpha(1);                    viewHolder.itemView.setTranslationX(dX);                }            }            @Override            public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {                super.onSelectedChanged(viewHolder, actionState);                //当选中Item时候会调用该方法，重写此方法可以实现选中时候的一些动画逻辑                Log.v("zxy", "onSelectedChanged");            }            @Override            public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {                super.clearView(recyclerView, viewHolder);                //当动画已经结束的时候调用该方法，重写此方法可以实现恢复Item的初始状态                 Log.v("zxy", "clearView");            }        };        new ItemTouchHelper(mCallback).attachToRecyclerView(recyclerView);    }
SimpleCallback构造方法需要我们传入两个参数：
1、dragDirs - 表示拖拽的方向，有六个类型的值：LEFT、RIGHT、START、END、UP、DOWN 
2、swipeDirs - 表示滑动的方向，有六个类型的值：LEFT、RIGHT、START、END、UP、DOWN 
【注】：如果为0，则表示不触发该操作（滑动or拖拽）
然后onMove和onSwiped分别是拖拽和滑动时回调的方法

=====================
temTouchHelper简单使用
要想通过ItemTouchHelper实现交互动画，只需要以下步骤：
定义一个ItemTouchHelper.Callback回调类，用于实现具体交互效果
创建一个ItemTouchHelper对象，并传入Callback对象
调用ItemTouchHelper对象的attachToRecyclerView方法，将ItemTouchHelper对象绑定到指定RecyclerView控件上。
代码如下：
public class MainActivity extends AppCompatActivity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        final List<String> datas = new ArrayList<>();        for (int i = 0; i < 20; i++) {            datas.add(String.valueOf(i));        }        RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recyclerview);                //1.设置适配器        LinearLayoutManager layoutManager = new LinearLayoutManager(this);        RecycleViewAdapter adapter = new RecycleViewAdapter(this, datas);        recyclerView.setLayoutManager(layoutManager);        recyclerView.setAdapter(adapter);                //2.设置ItemTouchHelper        ItemTouchHelper.Callback callback = new MyItemTouchHelperCallback(adapter);        ItemTouchHelper itemTouchHelper = new ItemTouchHelper(callback);        itemTouchHelper.attachToRecyclerView(recyclerView);}}
adpater
package example.com.itemtouchhelper;import android.content.Context;import android.support.v7.widget.RecyclerView;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.TextView;import java.util.Collections;import java.util.List;/** * Created by Administrator on 2016/12/6. */public class RecycleViewAdapter extends RecyclerView.Adapter<RecycleViewAdapter.ViewHolder> implements ItemTouchMoveListener {    private Context context;    private List<String> datas;    private final LayoutInflater mInflater;    public RecycleViewAdapter(Context context, List<String> datas) {        this.context = context;        this.datas = datas;        mInflater = LayoutInflater.from(context);    }    @Override    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {        return new ViewHolder(mInflater.inflate(R.layout.list_item, parent, false));    }    @Override    public void onBindViewHolder(ViewHolder holder, int position) {        System.out.println("=======" + position);        holder.iv_item.setText(datas.get(position));    }    @Override    public int getItemCount() {        return datas.size();    }    public static class ViewHolder extends RecyclerView.ViewHolder {        private TextView iv_item;        public ViewHolder(View itemView) {            super(itemView);            iv_item = (TextView) itemView.findViewById(R.id.iv_item);        }    }    /**     * 当Item上下拖动会调用该方法     *     * @param fromPosition     * @param toPosition     * @return     */    @Override    public boolean onItemMove(int fromPosition, int toPosition) {        Collections.swap(datas, fromPosition, toPosition);        notifyItemMoved(fromPosition, toPosition);        return true;    }    /**     * 当Item左右滑动时调用该方法     *     * @param position     * @return     */    @Override    public boolean onItemRemove(int position) {        datas.remove(position);        notifyItemRemoved(position);        return true;    }}

MyItemTouchHelperCallback
package example.com.itemtouchhelper;import android.graphics.Canvas;import android.graphics.Color;import android.support.v7.widget.RecyclerView;import android.support.v7.widget.helper.ItemTouchHelper;/** * Created by Administrator on 2016/12/6. */public class MyItemTouchHelperCallback extends ItemTouchHelper.Callback {    private ItemTouchMoveListener mItemTouchMoveListener;    public MyItemTouchHelperCallback(ItemTouchMoveListener listener) {        this.mItemTouchMoveListener = listener;    }    /**     * 设置RecyclerView支持拖动和滑动的方向     */    @Override    public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {        //支持上下拖动        int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;        //支持左右滑动        int swipeFlag = ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT;        int flags = makeMovementFlags(dragFlags, swipeFlag);        return flags;    }    /**     * 当上下拖动的时候调用该方法     */    @Override    public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {        if (viewHolder.getItemViewType() != target.getItemViewType()) {            // 当item的类型不一样的时候不能交换            return false;        }        boolean result = mItemTouchMoveListener.onItemMove(viewHolder.getAdapterPosition(), target.getAdapterPosition());//        boolean result = mItemTouchMoveListener.onItemMove(viewHolder.getLayoutPosition(), target.getLayoutPosition());        return result;    }    /**     * 当左右滑动的时候调用该方法     */    @Override    public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {        mItemTouchMoveListener.onItemRemove(viewHolder.getAdapterPosition());    }    /**     * 选中状态改变时监听     */    @Override    public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {        if (actionState != ItemTouchHelper.ACTION_STATE_IDLE) {            //不是空闲状态            viewHolder.itemView.setBackgroundColor(viewHolder.itemView.getContext().getResources().getColor(R.color.colorPrimary));        }        super.onSelectedChanged(viewHolder, actionState);    }    /**     * 恢复item状态     */    @Override    public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {        viewHolder.itemView.setBackgroundColor(Color.parseColor("#F9F9F9"));        super.clearView(recyclerView, viewHolder);    }    /**     * holde ItemView绘制，属性动画     */    @Override    public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {        //在左右滑动时，让item的透明度随着移动而改变，并缩放        float alpha = 1 - Math.abs(dX) / viewHolder.itemView.getWidth();        if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {            viewHolder.itemView.setAlpha(alpha);            viewHolder.itemView.setScaleX(alpha);            viewHolder.itemView.setScaleY(alpha);        }        //防止item复用出现问题，如果大家不理解下面这段代码，可以自行注释效果，        if (alpha <= 0) {            viewHolder.itemView.setAlpha(1);            viewHolder.itemView.setScaleX(1);            viewHolder.itemView.setScaleY(1);        }        super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);    }}

package example.com.itemtouchhelper;/** * Created by Administrator on 2016/12/6. */public interface ItemTouchMoveListener {    /**     * 当Item上下拖动时调用     */    boolean onItemMove(int fromPosition, int toPosition);    /**     * 当item左右滑动时调用     */    boolean onItemRemove(int position);}