时间戳

首页 > 解决方案 > Xamarin Android：选择recyclerview项目时如何不滑动recyclerview项目

c# - Xamarin Android：选择recyclerview项目时如何不滑动recyclerview项目

问题描述

大家好我叫谷口

我已经创建了一个 recyclerview 并插入了一个滑动回调，当向左滑动一个 recyclerview 项目时，这个项目将从 recyclerview 中删除。

我还完成了在 recyclerview 上选择项目。

不，我想这样做，如果选择了 recyclerview 上的一个项目，就无法滑动任何 recyclerview 项目。

我试图对 recyclerview 进行重新计费，但是在创建 recyclerview 时插入了滑动回调，并且没有何时进行计费

选择 recyclerview 项目时，如何使无法滑动？

我的滑动回调：

public class SwipeToDeleteCallback : ItemTouchHelper.SimpleCallback
{
    private View v;
    private List<Email> mEmails;
    private Context context;
    private RecyclerAdapter mdapter;
    private Android.Graphics.Drawables.Drawable deleteIcon;
    private int intrinsicWidth;
    private int intrinsicHeight;
    private Android.Graphics.Drawables.ColorDrawable background;
    private Color backgroundColor;
    private Paint clearPaint;

    public SwipeToDeleteCallback(int dragDirs, int swipeDirs, Context context) : base(dragDirs, swipeDirs)
    {
        this.context = context;
        deleteIcon = ContextCompat.GetDrawable(context, Resource.Drawable.alter_delete);
        intrinsicWidth = deleteIcon.IntrinsicWidth;
        intrinsicHeight = deleteIcon.IntrinsicHeight;
        background = new Android.Graphics.Drawables.ColorDrawable();
        backgroundColor = Color.ParseColor("#f44336");
        clearPaint = new Paint();
        clearPaint.SetXfermode(new PorterDuffXfermode(PorterDuff.Mode.Clear));
    }

    public SwipeToDeleteCallback(int dragDirs, int swipeDirs, Context context, RecyclerAdapter mRecyclerView, List<Email> mails) : this(dragDirs, swipeDirs, context)
    {
        this.context = context;
        this.mdapter = mRecyclerView;
        deleteIcon = ContextCompat.GetDrawable(context, Resource.Drawable.alter_delete);
        intrinsicWidth = deleteIcon.IntrinsicWidth;
        intrinsicHeight = deleteIcon.IntrinsicHeight;
        background = new Android.Graphics.Drawables.ColorDrawable();
        backgroundColor = Color.ParseColor("#f44336");
        clearPaint = new Paint();
        mEmails = mails;
        clearPaint.SetXfermode(new PorterDuffXfermode(PorterDuff.Mode.Clear));
    }

    public override int GetMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder)
    {
        if (viewHolder.AdapterPosition == 10)
        {
            return 0;
        }
        return base.GetMovementFlags(recyclerView, viewHolder);
    }

    public override void OnChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, bool isCurrentlyActive)
    {
        base.OnChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
    }

    public override bool OnMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target)
    {
        //throw new NotImplementedException();
        return false;
    }

    public override void OnChildDrawOver(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, bool isCurrentlyActive)
    {
        var itemView = viewHolder.ItemView;
        var itemHeight = itemView.Bottom - itemView.Top;
        var isCanceled = dX == 0f && !isCurrentlyActive;

        if (isCanceled)
        {
            clearCanvas(c, itemView.Right + dX, (float)itemView.Top, (float)itemView.Right, (float)itemView.Bottom);
            base.OnChildDrawOver(c, recyclerView
                , viewHolder, dX, dY, actionState, isCurrentlyActive);
            return;
        }
        background.Color = backgroundColor;
        background.SetBounds(itemView.Right + (int)dX, itemView.Top, itemView.Right, itemView.Bottom);
        background.Draw(c);

        var deleteIconTop = itemView.Top + (itemHeight - intrinsicHeight) / 2;
        var deleteIconMargin = (itemHeight - intrinsicHeight) / 2;
        var deleteIconLeft = itemView.Right - deleteIconMargin - intrinsicWidth;
        var deleteIconRight = itemView.Right - deleteIconMargin;
        var deleteIconBottom = deleteIconTop + intrinsicHeight;

        deleteIcon.SetBounds(deleteIconLeft, deleteIconTop, deleteIconRight, deleteIconBottom);
        deleteIcon.Draw(c);

        base.OnChildDrawOver(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
    }

    private void clearCanvas(Canvas c, float v, float top, float right, float bottom)
    {
        c.DrawRect(v, top, right, bottom, clearPaint);
    }

    public override void OnSwiped(RecyclerView.ViewHolder viewHolder, int direction)
    {
        //Invoke Removing Item method from 
        int position = viewHolder.AdapterPosition;
        RecyclerAdapter mAdapter = new RecyclerAdapter(mEmails, this);
        mAdapter.RemoveItem(viewHolder.AdapterPosition);

    }

    public override void ClearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder)
    {
        mdapter.RemoveItem(viewHolder.AdapterPosition);
    }
}

我的 recyclerview 适配器：

public class RecyclerAdapter : RecyclerView.Adapter
{

    public static RecyclerView.Adapter mAdapter;
    public static bool isActionMode = true;
    public static bool unselect = false;
    private Activity mActivity;
    private List<Email> mEmails;
    private Context context;
    private View p;
    public static bool count = false;
    public static int CountAuxiliar = 0;
    private SwipeToDeleteCallback swipeToDeleteCallback;

    private Boolean isSelected = false;

    public Boolean IsSelected()
    {
        return isSelected;
    }

    public void setSelected(Boolean selected)
    {
        isSelected = selected;
    }

    public RecyclerAdapter(List<Email> emails, Context context)
    {
        mEmails = emails;
        this.context = context;
    }

    public RecyclerAdapter(List<Email> emails, Activity activity)
    {
        mEmails = emails;
        mActivity = activity;
    }

    public RecyclerAdapter(List<Email> mEmails, SwipeToDeleteCallback swipeToDeleteCallback)
    {
        this.mEmails = mEmails;
        this.swipeToDeleteCallback = swipeToDeleteCallback;
    }

    public class MyView : RecyclerView.ViewHolder
    {
        public View mMainView { get; set; }
        public TextView mName { get; set; }
        public TextView mSubject { get; set; }
        public TextView mMessage { get; set; }

        public MyView(View view) : base(view)
        {
            mMainView = view;
        }

    }

    public override int ItemCount
    {
        get { return mEmails.Count; }
    }

    public override RecyclerView.ViewHolder OnCreateViewHolder(ViewGroup parent, int viewType)
    {
        LayoutInflater inflater = LayoutInflater.From(parent.Context);
        View row = LayoutInflater.From(parent.Context).Inflate(Resource.Layout.row, parent, false);
        RecyclerViewHolder vh = new RecyclerViewHolder(row);
        return vh;
    }
    public override void OnBindViewHolder(RecyclerView.ViewHolder holder, int position)
    {
        RecyclerViewHolder myHolder = holder as RecyclerViewHolder;

        myHolder.mName.Text = mEmails[position].Name;
        myHolder.mSubject.Text = mEmails[position].Subject;
        myHolder.mMessage.Text = mEmails[position].Message;
    }

    public void RemoveItem(int position)
    {
        mEmails.RemoveAt(position);
        NotifyDataSetChanged();
        NotifyItemChanged(position);
    }
}

我在哪里调用我的 recyclerview 和滑动回调：

public class MainActivity : AppCompatActivity
{
    public static RecyclerView mRecyclerView;
    public static RecyclerView.LayoutManager mLayoutManager;
    public RecyclerView.ViewHolder holder;
    public static BottomNavigationView bottomnavigationview1;
    public static RecyclerView.Adapter mAdapter;
    public static List<Email> mEmails;


    protected override void OnCreate(Bundle bundle)
    {
        base.OnCreate(bundle);
        Xamarin.Essentials.Platform.Init(this, bundle);
        // Set our view from the "main" layout resource
        SetContentView(Resource.Layout.activity_main);

        mRecyclerView = FindViewById<RecyclerView>(Resource.Id.recyclerViwer);
        mRecyclerView.AddItemDecoration(new DividerItemDecoration(mRecyclerView.Context, DividerItemDecoration.Vertical));
        mRecyclerView.HasFixedSize = true;
        SetupList();

        //Create our layout Manager
        mLayoutManager = new LinearLayoutManager(this);
        mRecyclerView.SetLayoutManager(mLayoutManager);
        RecyclerAdapter mAdapter = new RecyclerAdapter(mEmails, this);
        mRecyclerView.SetAdapter(mAdapter);

        var swipeHandler = new SwipeToDeleteCallback(0, ItemTouchHelper.Left, this, mAdapter, mEmails);
        var itemTouchHelper = new ItemTouchHelper(swipeHandler);
        itemTouchHelper.AttachToRecyclerView(mRecyclerView);


    }

    private void SetupList()
    {
        for (int i = 1; i <= 2; i++)
        {
            mEmails = new List<Email>();
            mEmails.Add(new Email() { Name = "tom", Subject = "Wanna Hang Out?", Message = "I ' ll   be around  tomorrow!!" });
            mEmails.Add(new Email() { Name = "tom", Subject = "Wanna Hang Out?", Message = "I ' ll   be around  tomorrow!!" });
            mEmails.Add(new Email() { Name = "tom", Subject = "Wanna Hang Out?", Message = "I ' ll   be around  tomorrow!!" });
            mEmails.Add(new Email() { Name = "tom", Subject = "Wanna Hang Out?", Message = "I ' ll   be around  tomorrow!!" });
        }
    }

标签： c#xamarin.android

解决方案

选择 recyclerview 项目时，如何使无法滑动？

如果你从 recyclerview 中选择项目，你不想刷这个项目？请看下面的代码。

  1. 在 RecyclerAdapter 类中创建选择位置。为 selectionposition 设置选择项位置。

    public int selectionposition;

  2. 更改 OnBindViewHolder。

    public override void OnBindViewHolder(RecyclerView.ViewHolder holder, int position)
{
    RecyclerViewHolder myHolder = holder as RecyclerViewHolder;

    myHolder.mName.Text = mEmails[position].Name;
    myHolder.mSubject.Text = mEmails[position].Subject;
    myHolder.mMessage.Text = mEmails[position].Message;

    myHolder.ItemView.Click += (sender, e) =>
      {
          selectionposition = position;
          NotifyDataSetChanged();
      };
}

  3. 更改 getMovementFlags 方法，如果选择项位置 = 选择位置，则不要滑动该项。

    public override int GetMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder)
{
    if (viewHolder.AdapterPosition == 10)
    {
        return 0;
    }
    if(viewHolder.AdapterPosition==mdapter.selectionposition)
    {
        return 0;
    }
    return base.GetMovementFlags(recyclerView, viewHolder);
}

推荐阅读