Add swipe-to-delete for notes

Mårten Åsberg committed on 2026-08-01 at 22:21

Swiping a row in the note list either direction reveals a red
delete background via a shared ItemTouchHelper.SimpleCallback, then
prompts for confirmation before anything happens - cancelling (button
or dismissal) snaps the row back with NotifyItemChanged, confirming
deletes the file from OneDrive (GraphService.DeleteNoteAsync) and
removes it from the cache and adapter.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Browse files at this commit

src/Activities/NoteListActivity.cs +52 -0

diff --git a/src/Activities/NoteListActivity.cs b/src/Activities/NoteListActivity.cs
index 84d5011..5c1c5f3 100644
@@ -9,6 +9,7 @@ using NotesApp.Graph;
using NotesApp.Models;
using NotesApp.Storage;
using NotesApp.Views;
using AlertDialog = AndroidX.AppCompat.App.AlertDialog;
using Toolbar = AndroidX.AppCompat.Widget.Toolbar;
namespace NotesApp.Activities;
@@ -45,6 +46,10 @@ public class NoteListActivity : AppCompatActivity
        FindViewById<FloatingActionButton>(Resource.Id.new_note_fab)!.Click += (_, _) =>
            OnNewNoteClicked();
        new ItemTouchHelper(new SwipeToDeleteCallback(OnNoteSwiped, this)).AttachToRecyclerView(
            _recyclerView
        );
        _graphService = new GraphService(this);
        // Cache renders immediately, scrolled to the bottom, before any network call.
@@ -159,6 +164,53 @@ public class NoteListActivity : AppCompatActivity
        StartActivityForResult(intent, EditNoteRequestCode);
    }
    private void OnNoteSwiped(int position)
    {
        var entry = _adapter.GetItem(position);
        var dialog = new AlertDialog.Builder(this)!
            .SetTitle(Resource.String.delete_note_title)!
            .SetMessage(string.Format(GetString(Resource.String.delete_note_message), entry.Name))!
            .SetPositiveButton(
                Resource.String.delete,
                (_, _) => _ = DeleteNoteAsync(entry, position)
            )!
            .SetNegativeButton(
                Resource.String.cancel,
                (_, _) => _adapter.NotifyItemChanged(position)
            )!
            .Create()!;
        // Covers dismissal via back press or tapping outside the dialog - button clicks
        // dismiss without cancelling, so this doesn't double-fire alongside SetNegativeButton.
        dialog.CancelEvent += (_, _) => _adapter.NotifyItemChanged(position);
        dialog.Show();
    }
    private async Task DeleteNoteAsync(NoteCacheEntry entry, int position)
    {
        _progressBar.Visibility = ViewStates.Visible;
        try
        {
            await _graphService.DeleteNoteAsync(entry.Id);
            var list = NoteCacheStore.Load();
            list.RemoveAll(e => e.Id == entry.Id);
            NoteCacheStore.Save(list);
            _adapter.RemoveAt(position);
        }
        catch (Exception ex)
        {
            var message = string.Format(GetString(Resource.String.delete_failed), ex.Message);
            Toast.MakeText(this, message, ToastLength.Long)?.Show();
            _adapter.NotifyItemChanged(position);
        }
        finally
        {
            _progressBar.Visibility = ViewStates.Invisible;
        }
    }
    private void BindItems(List<NoteCacheEntry> entries)
    {
        _adapter.SetItems(entries);

src/Adapters/NoteListAdapter.cs +8 -0

diff --git a/src/Adapters/NoteListAdapter.cs b/src/Adapters/NoteListAdapter.cs
index 7809e7b..cda08f3 100644
@@ -16,6 +16,14 @@ public class NoteListAdapter(Action<NoteCacheEntry> onNoteTapped) : RecyclerView
        NotifyDataSetChanged();
    }
    public NoteCacheEntry GetItem(int position) => _items[position];
    public void RemoveAt(int position)
    {
        _items.RemoveAt(position);
        NotifyItemRemoved(position);
    }
    public override RecyclerView.ViewHolder OnCreateViewHolder(ViewGroup parent, int viewType)
    {
        var view = LayoutInflater

src/Graph/GraphService.cs +6 -0

diff --git a/src/Graph/GraphService.cs b/src/Graph/GraphService.cs
index 5f4625d..b2fd760 100644
@@ -245,4 +245,10 @@ public class GraphService
        var (eTag, lastModified, size) = await PutContentAsync(newId, content, ct);
        return new NoteCacheEntry(newId, fileName, eTag, lastModified, preview, size);
    }
    public async Task DeleteNoteAsync(string itemId, CancellationToken ct = default)
    {
        var driveId = await GetDriveIdAsync(ct);
        await _client.Drives[driveId].Items[itemId].DeleteAsync(cancellationToken: ct);
    }
}

src/Resources/drawable/ic_delete_24.xml +13 -0

diff --git a/src/Resources/drawable/ic_delete_24.xml b/src/Resources/drawable/ic_delete_24.xml
new file mode 100644
index 0000000..ddd506b
@@ -0,0 +1,13 @@
<?xml version="1.0" encoding="utf-8"?>
<vector
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:width="24dp"
  android:height="24dp"
  android:viewportWidth="24"
  android:viewportHeight="24"
>
  <path
    android:fillColor="#FFFFFFFF"
    android:pathData="M6,19c0,1.1 0.9,2 2,2h8c1.1,0 2,-0.9 2,-2L18,7L6,7L6,19zM19,4h-3.5l-1,-1h-5l-1,1L5,4v2h14L19,4z"
  />
</vector>

src/Resources/values/strings.xml +5 -0

diff --git a/src/Resources/values/strings.xml b/src/Resources/values/strings.xml
index 53c38ae..3a50b9f 100644
@@ -24,4 +24,9 @@
  <string name="discard">Discard</string>
  <string name="cancel">Cancel</string>
  <string name="save_failed">Save failed: {0}</string>
  <string name="delete_note_title">Delete note?</string>
  <string name="delete_note_message">{0} will be permanently deleted.</string>
  <string name="delete">Delete</string>
  <string name="delete_failed">Delete failed: {0}</string>
</resources>

src/Views/SwipeToDeleteCallback.cs +91 -0

diff --git a/src/Views/SwipeToDeleteCallback.cs b/src/Views/SwipeToDeleteCallback.cs
new file mode 100644
index 0000000..48afac7
@@ -0,0 +1,91 @@
using Android.Content;
using Android.Graphics;
using Android.Graphics.Drawables;
using AndroidX.Core.Content;
using AndroidX.RecyclerView.Widget;
namespace NotesApp.Views;
// Renders the red delete background + trash icon behind a row as it's swiped. OnSwiped only
// reports the position - the caller decides whether to actually delete (after confirmation)
// or snap the row back via NotifyItemChanged.
public class SwipeToDeleteCallback(Action<int> onSwiped, Context context)
    : ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.Left | ItemTouchHelper.Right)
{
    private const int IconMarginDp = 16;
    private readonly ColorDrawable _background = new(Color.ParseColor("#D32F2F"));
    private readonly Drawable? _icon = ContextCompat.GetDrawable(
        context,
        Resource.Drawable.ic_delete_24
    );
    private readonly float _density = context.Resources!.DisplayMetrics!.Density;
    public override bool OnMove(
        RecyclerView recyclerView,
        RecyclerView.ViewHolder viewHolder,
        RecyclerView.ViewHolder target
    ) => false;
    public override void OnSwiped(RecyclerView.ViewHolder viewHolder, int direction) =>
        onSwiped(viewHolder.BindingAdapterPosition);
    public override void OnChildDraw(
        Canvas c,
        RecyclerView recyclerView,
        RecyclerView.ViewHolder viewHolder,
        float dX,
        float dY,
        int actionState,
        bool isCurrentlyActive
    )
    {
        var itemView = viewHolder.ItemView;
        var iconMargin = (int)(IconMarginDp * _density);
        var iconWidth = _icon?.IntrinsicWidth ?? 0;
        var iconHeight = _icon?.IntrinsicHeight ?? 0;
        var iconTop = itemView.Top + (itemView.Height - iconHeight) / 2;
        var iconBottom = iconTop + iconHeight;
        if (dX > 0)
        {
            _background.SetBounds(
                itemView.Left,
                itemView.Top,
                itemView.Left + (int)dX,
                itemView.Bottom
            );
            _icon?.SetBounds(
                itemView.Left + iconMargin,
                iconTop,
                itemView.Left + iconMargin + iconWidth,
                iconBottom
            );
        }
        else if (dX < 0)
        {
            _background.SetBounds(
                itemView.Right + (int)dX,
                itemView.Top,
                itemView.Right,
                itemView.Bottom
            );
            _icon?.SetBounds(
                itemView.Right - iconMargin - iconWidth,
                iconTop,
                itemView.Right - iconMargin,
                iconBottom
            );
        }
        else
        {
            _background.SetBounds(0, 0, 0, 0);
        }
        _background.Draw(c);
        if (dX != 0)
            _icon?.Draw(c);
        base.OnChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
    }
}