android Recycleview的侧滑点击删除功能实现

直接上代码:

继承RecyclerView，可侧滑删除

public class SlideRecyclerView extends RecyclerView {
    private static final String TAG = "SlideRecyclerView";
    private static final int INVALID_POSITION = -1; // 触摸到的点不在子View范围内
    private static final int INVALID_CHILD_WIDTH = -1;  // 子ItemView不含两个子View
    private static final int SNAP_VELOCITY = 600;   // 最小滑动速度

    private VelocityTracker mVelocityTracker;   // 速度追踪器
    private int mTouchSlop; // 认为是滑动的最小距离（一般由系统提供）
    private Rect mTouchFrame;   // 子View所在的矩形范围
    private Scroller mScroller;
    private float mLastX;   // 滑动过程中记录上次触碰点X
    private float mFirstX, mFirstY; // 首次触碰范围
    private boolean mIsSlide;   // 是否滑动子View
    private ViewGroup mFlingView;   // 触碰的子View
    private int mPosition;  // 触碰的view的位置
    private int mMenuViewWidth;    // 菜单按钮宽度

    public SlideRecyclerView(Context context) {
        this(context, null);
    }

    public SlideRecyclerView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public SlideRecyclerView(Context context, @Nullable AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();
        mScroller = new Scroller(context);
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent e) {
        int x = (int) e.getX();
        int y = (int) e.getY();
        obtainVelocity(e);
        switch (e.getAction()) {
            case MotionEvent.ACTION_DOWN:
                if (!mScroller.isFinished()) {  // 如果动画还没停止，则立即终止动画
                    mScroller.abortAnimation();
                }
                mFirstX = mLastX = x;
                mFirstY = y;
                mPosition = pointToPosition(x, y);  // 获取触碰点所在的position
                if (mPosition != INVALID_POSITION) {
                    View view = mFlingView;
                    // 获取触碰点所在的view
                    mFlingView = (ViewGroup) getChildAt(mPosition - ((LinearLayoutManager) getLayoutManager()).findFirstVisibleItemPosition());
                    // 这里判断一下如果之前触碰的view已经打开，而当前碰到的view不是那个view则立即关闭之前的view，此处并不需要担动画没完成冲突，因为之前已经abortAnimation
                    if (view != null && mFlingView != view && view.getScrollX() != 0) {
                        view.scrollTo(0, 0);
                    }
                    // 这里进行了强制的要求，RecyclerView的子ViewGroup必须要有2个子view,这样菜单按钮才会有值，
                    // 需要注意的是:如果不定制RecyclerView的子View，则要求子View必须要有固定的width。
                    // 比如使用LinearLayout作为根布局，而content部分width已经是match_parent，此时如果菜单view用的是wrap_content，menu的宽度就会为0。
                    if (mFlingView.getChildCount() == 2) {
                        mMenuViewWidth = mFlingView.getChildAt(1).getWidth();
                    } else {
                        mMenuViewWidth = INVALID_CHILD_WIDTH;
                    }
                }
                break;
            case MotionEvent.ACTION_MOVE:
                mVelocityTracker.computeCurrentVelocity(1000);
                // 此处有俩判断，满足其一则认为是侧滑：
                // 1.如果x方向速度大于y方向速度，且大于最小速度限制；
                // 2.如果x方向的侧滑距离大于y方向滑动距离，且x方向达到最小滑动距离；
                float xVelocity = mVelocityTracker.getXVelocity();
                float yVelocity = mVelocityTracker.getYVelocity();
                if (Math.abs(xVelocity) > SNAP_VELOCITY && Math.abs(xVelocity) > Math.abs(yVelocity)
                        || Math.abs(x - mFirstX) >= mTouchSlop
                        && Math.abs(x - mFirstX) > Math.abs(y - mFirstY)) {
                    mIsSlide = true;
                    return true;
                }
                break;
            case MotionEvent.ACTION_UP:
                releaseVelocity();
                break;
        }
        return super.onInterceptTouchEvent(e);
    }

    @Override
    public boolean onTouchEvent(MotionEvent e) {
        if (mIsSlide && mPosition != INVALID_POSITION) {
            float x = e.getX();
            obtainVelocity(e);
            switch (e.getAction()) {
                case MotionEvent.ACTION_DOWN:   // 因为没有拦截，所以不会被调用到
                    break;
                case MotionEvent.ACTION_MOVE:
                    // 随手指滑动
                    if (mMenuViewWidth != INVALID_CHILD_WIDTH) {
                        float dx = mLastX - x;
                        if (mFlingView.getScrollX() + dx <= mMenuViewWidth
                                && mFlingView.getScrollX() + dx > 0) {
                            mFlingView.scrollBy((int) dx, 0);
                        }
                        mLastX = x;
                    }
                    break;
                case MotionEvent.ACTION_UP:
                    if (mMenuViewWidth != INVALID_CHILD_WIDTH) {
                        int scrollX = mFlingView.getScrollX();
                        mVelocityTracker.computeCurrentVelocity(1000);
                        // 此处有两个原因决定是否打开菜单：
                        // 1.菜单被拉出宽度大于菜单宽度一半；
                        // 2.横向滑动速度大于最小滑动速度；
                        // 注意：之所以要小于负值，是因为向左滑则速度为负值
                        if (mVelocityTracker.getXVelocity() < -SNAP_VELOCITY) {    // 向左侧滑达到侧滑最低速度，则打开
                            mScroller.startScroll(scrollX, 0, mMenuViewWidth - scrollX, 0, Math.abs(mMenuViewWidth - scrollX));
                        } else if (mVelocityTracker.getXVelocity() >= SNAP_VELOCITY) {  // 向右侧滑达到侧滑最低速度，则关闭
                            mScroller.startScroll(scrollX, 0, -scrollX, 0, Math.abs(scrollX));
                        } else if (scrollX >= mMenuViewWidth / 2) { // 如果超过删除按钮一半，则打开
                            mScroller.startScroll(scrollX, 0, mMenuViewWidth - scrollX, 0, Math.abs(mMenuViewWidth - scrollX));
                        } else {    // 其他情况则关闭
                            mScroller.startScroll(scrollX, 0, -scrollX, 0, Math.abs(scrollX));
                        }
                        invalidate();
                    }
                    mMenuViewWidth = INVALID_CHILD_WIDTH;
                    mIsSlide = false;
                    mPosition = INVALID_POSITION;
                    releaseVelocity();  // 这里之所以会调用，是因为如果前面拦截了，就不会执行ACTION_UP,需要在这里释放追踪
                    break;
            }
            return true;
        } else {
            // 此处防止RecyclerView正常滑动时，还有菜单未关闭
            closeMenu();
            // Velocity，这里的释放是防止RecyclerView正常拦截了，但是在onTouchEvent中却没有被释放；
            // 有三种情况：1.onInterceptTouchEvent并未拦截，在onInterceptTouchEvent方法中，DOWN和UP一对获取和释放；
            // 2.onInterceptTouchEvent拦截，DOWN获取，但事件不是被侧滑处理，需要在这里进行释放；
            // 3.onInterceptTouchEvent拦截，DOWN获取，事件被侧滑处理，则在onTouchEvent的UP中释放。
            releaseVelocity();
        }
        return super.onTouchEvent(e);
    }

    private void releaseVelocity() {
        if (mVelocityTracker != null) {
            mVelocityTracker.clear();
            mVelocityTracker.recycle();
            mVelocityTracker = null;
        }
    }

    private void obtainVelocity(MotionEvent event) {
        if (mVelocityTracker == null) {
            mVelocityTracker = VelocityTracker.obtain();
        }
        mVelocityTracker.addMovement(event);
    }

    public int pointToPosition(int x, int y) {
        int firstPosition = ((LinearLayoutManager) getLayoutManager()).findFirstVisibleItemPosition();
        Rect frame = mTouchFrame;
        if (frame == null) {
            mTouchFrame = new Rect();
            frame = mTouchFrame;
        }

        final int count = getChildCount();
        for (int i = count - 1; i >= 0; i--) {
            final View child = getChildAt(i);
            if (child.getVisibility() == View.VISIBLE) {
                child.getHitRect(frame);
                if (frame.contains(x, y)) {
                    return firstPosition + i;
                }
            }
        }
        return INVALID_POSITION;
    }

    @Override
    public void computeScroll() {
        if (mScroller.computeScrollOffset()) {
            mFlingView.scrollTo(mScroller.getCurrX(), mScroller.getCurrY());
            invalidate();
        }
    }

    /**
     * 将显示子菜单的子view关闭
     * 这里本身是要自己来实现的，但是由于不定制item，因此不好监听器点击事件，因此需要调用者手动的关闭
     */
    public void closeMenu() {
        if (mFlingView != null && mFlingView.getScrollX() != 0) {
            mFlingView.scrollTo(0, 0);
        }
    }
}

RecyclerAdapter:

public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
    private final List<String> mDatas;//数据
    private final int TYPE_ITEM = 0;//正常的Item
    private final int TYPE_FOOT = 1;//尾部刷新

    private final Context mContext;

    private boolean hasMore = true;

    public RecyclerAdapter(List<String> mDatas, Context mContext) {
        this.mDatas = mDatas;
        this.mContext = mContext;
    }

    //第一步 定义接口
    public interface OnItemClickListener {
        void onClick(String str, int position);
        void onClickDelete(String str,int position);
    }

    private OnItemClickListener mListener;

    //第二步， 写一个公共的方法
    public void setOnItemClickListener(OnItemClickListener listener) {
        this.mListener = listener;
    }

    //返回不同布局
    @Override
    public int getItemViewType(int position) {
        if (position == getItemCount() - 1) {
            //尾部刷新
            return TYPE_FOOT;
        }
        return TYPE_ITEM;
    }

    @NonNull
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        if (viewType == TYPE_ITEM) {
            return new ItemHolder(LayoutInflater.from(mContext).inflate(R.layout.item_rv, parent, false));
        } else {
            return new FootHolder(LayoutInflater.from(mContext).inflate(R.layout.item_foot, parent, false));
        }
    }

    @SuppressLint("SetTextI18n")
    @Override
    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, @SuppressLint("RecyclerView") int position) {

        if (holder instanceof ItemHolder) {
            ((ItemHolder) holder).tv_item.setText("测试" + mDatas.get(position));
            ((ItemHolder) holder).item_delete.setOnClickListener(v ->
                    mListener.onClickDelete(mDatas.get(position), position));
            holder.itemView.setOnClickListener(v ->
                    mListener.onClick(mDatas.get(position), position));
        } else {
            if (hasMore) {
                ((FootHolder) holder).tv_foot.setText("正在加载更多。。");
                ((FootHolder) holder).iv_foot.setVisibility(View.VISIBLE);
            } else {
                ((FootHolder) holder).tv_foot.setText("没有更多数据。。");
                ((FootHolder) holder).iv_foot.setVisibility(View.GONE);
            }
        }
    }

    //多出尾部刷新的item
    @Override
    public int getItemCount() {
        return mDatas.size() + 1;
    }

    //item的holder
    static class ItemHolder extends RecyclerView.ViewHolder {
        private final TextView tv_item;
        private final TextView item_delete;

        public ItemHolder(View itemView) {
            super(itemView);
            tv_item = itemView.findViewById(R.id.tv_item);
            item_delete = itemView.findViewById(R.id.item_delete);
        }
    }

    static class FootHolder extends RecyclerView.ViewHolder {
        private final TextView tv_foot;
        private final ImageView iv_foot;

        public FootHolder(View itemView) {
            super(itemView);
            tv_foot = itemView.findViewById(R.id.tv_foot);
            iv_foot = itemView.findViewById(R.id.iv_foot);
        }
    }

    //是否有更多数据
    public void hasMore(boolean more) {
        this.hasMore = more;
    }

    //这里清空数据，避免下拉刷新后，还显示上拉加载的数据
    public void reData() {
        mDatas.clear();
    }
}

MainActivity的实现:

public class MainActivity extends AppCompatActivity implements SwipeRefreshLayout.OnRefreshListener{
    private SlideRecyclerView recyclerView;
    private SwipeRefreshLayout swipeRefreshLayout;
    private List<String> mList;
    private RecyclerAdapter adapter;
    private int reTimes = 0;//更新次数

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
        getData();
        initRecyclerView();
    }

    private void initView() {
        recyclerView = findViewById(R.id.rv_home);
        swipeRefreshLayout = findViewById(R.id.sr_refresh);
        swipeRefreshLayout.setOnRefreshListener(this);
        mList = new ArrayList<>();
    }

    /**
     * 初始化RecyclerView
     */
    private void initRecyclerView() {
        adapter = new RecyclerAdapter(mList, this);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        recyclerView.setItemAnimator(new DefaultItemAnimator());
        recyclerView.setAdapter(adapter);

        adapter.setOnItemClickListener(new RecyclerAdapter.OnItemClickListener() {
            @Override
            public void onClick(String str, int position) {
                //点击条目
                Toast.makeText(MainActivity.this,"点击："+position,Toast.LENGTH_SHORT).show();
            }

            @SuppressLint("NotifyDataSetChanged")
            @Override
            public void onClickDelete(String str, int position) {
                int indexOf = mList.indexOf(str);
                if (-1 != indexOf){
                    mList.remove(indexOf);
                }
                adapter.notifyItemRemoved(position);
                if (position != mList.size()) {
                    //防止数据错乱
                    adapter.notifyItemRangeChanged(position, mList.size() - position);
                }

            }
        });

        recyclerView.setOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
                super.onScrollStateChanged(recyclerView, newState);
                //滑动到底部
                if (newState == RecyclerView.SCROLL_STATE_IDLE) {
                    //recyclerview滑动到底部,更新数据
                    //加载更多数据
                    new Handler().postDelayed(new Runnable() {
                        @SuppressLint("NotifyDataSetChanged")
                        @Override
                        public void run() {
                            if (reTimes < 1) {
                                getMoreData();
                                //告诉他有更多数据
                                adapter.hasMore(true);
                                adapter.notifyDataSetChanged();
                            } else {
                                //没有数据了
                                adapter.hasMore(false);
                                adapter.notifyDataSetChanged();
                            }
                        }
                    }, 2000);
                } else {//滑上去了
                    adapter.hasMore(true);
//                    adapter.notifyDataSetChanged();
                }
            }
        });

    }

    //刷新事件
    @Override
    public void onRefresh() {
        //显示刷新动画效果
        swipeRefreshLayout.setRefreshing(true);
        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                //清空数据
                adapter.reData();
                //重新获取数据
                getData();
                //更新的数据
                upData();
                //重新设置有更多数据
                adapter.hasMore(true);
                reTimes = 0;
                adapter.notifyDataSetChanged();
                //隐藏刷新效果
                swipeRefreshLayout.setRefreshing(false);
            }
        }, 1000);
    }

    //获取数据
    public void getData() {
        for (int i = 0; i < 20; i++) {
            mList.add(i + "");
        }
    }

    //加载更多数据
    public void getMoreData() {
        reTimes++;
        List<String> moreList = new ArrayList<>();
        for (int i = 0; i < 20; i++) {
            moreList.add("加载的数据" + i);
        }
        mList.addAll(moreList);
    }

    //更新数据
    private void upData() {
        for (int i = 0; i < 5; i++) {
            mList.add(0, "更新的数据" + i);
        }
    }

}

activity_main:

<?xml version="1.0" encoding="utf-8"?>
<androidx.swiperefreshlayout.widget.SwipeRefreshLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/sr_refresh"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.yichen.recycvewdemostand.SlideRecyclerView
        android:id="@+id/rv_home"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</androidx.swiperefreshlayout.widget.SwipeRefreshLayout>

item_foot:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">
    <ImageView
        android:id="@+id/iv_foot"
        android:layout_width="50dp"
        android:layout_height="30dp"
        android:background="@mipmap/ic_launcher"/>
    <TextView
        android:id="@+id/tv_foot"
        android:layout_toRightOf="@id/iv_foot"
        android:layout_width="match_parent"
        android:layout_height="30dp"
        android:gravity="center"/>
</RelativeLayout>

item_delete:也是条目的布局文件

<?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="50dp"
    android:orientation="horizontal">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <TextView
            android:id="@+id/tv_item"
            android:layout_width="match_parent"
            android:layout_height="50dp"
            android:gravity="center"/>

    </LinearLayout>


    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="64dp"
        android:layout_height="50dp">
        <TextView
            android:id="@+id/jianyi_zhiding"
            android:text="编辑"
            android:visibility="gone"
            android:background="#eaeaea"
            android:textColor="#222222"
            android:gravity="center"
            android:textAlignment="center"
            android:layout_width="64dp"
            android:layout_height="match_parent" />
        <TextView
            android:id="@+id/item_delete"
            android:text="删除"
            android:background="#D52619"
            android:gravity="center"
            android:textColor="#FFFFFF"
            android:textAlignment="center"
            android:layout_width="64dp"
            android:layout_height="match_parent" />

    </LinearLayout>
</LinearLayout>

以上!