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Draw string on a button

I want do draw a custom string on the bottom right of an button with an PlatformEffect. Prefer to use an effect to be more flexible and apply this only to specific buttons and not application wide. The buttons are created dynamically without xaml.
Is this possible or do i need to create a custom button + renderer?
Thanks.

You could create your Custom button and then set the text alignment via custom renderer.
[assembly: ExportRenderer(typeof(Xamarin.Forms.Button), typeof(ButtonCustomRenderer))]//set the Button as your custom button
namespace App3.Droid
{
public class ButtonCustomRenderer : ButtonRenderer
{
public ButtonCustomRenderer(Context context) : base(context)
{
}
protected override void OnElementChanged(ElementChangedEventArgs<Xamarin.Forms.Button> e)
{
base.OnElementChanged(e);
Control.Gravity = GravityFlags.End // Set the horizontal text alignment to right
| GravityFlags.Bottom; // Set the vertical text alignment to bottom
}
}
}

I solved it by creating a renderer which overrides the Draw method.
public class HotkeyButtonRenderer : ButtonRenderer
{
HotkeyButton element;
public HotkeyButtonRenderer(Context ctx) : base(ctx)
{
}
protected override void OnElementChanged(ElementChangedEventArgs<Button> e)
{
base.OnElementChanged(e);
element = Element as HotkeyButton;
SetWillNotDraw(false);
}
protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
base.OnElementPropertyChanged(sender, e);
if (element != null && e.PropertyName == HotkeyButton.HotkeyTextProperty.PropertyName)
{
Invalidate();
}
}
public override void Draw(Canvas canvas)
{
base.Draw(canvas);
if (element != null && !string.IsNullOrEmpty(element.HotkeyText))
{
string textToDraw = string.Format("({0})", element.HotkeyText);
float textSize = Control.TextSize / 1.5f;
SizeF measuredTextSize = GetTextSize(textToDraw, element.FontFamily, textSize);
float x = 5;
float y = Height-measuredTextSize.Height/2;
canvas.DrawText(textToDraw,
x,
y,
new TextPaint
{
Color = element.BorderColor.ToAndroid(),
TextSize = textSize
});
}
}
private SizeF GetTextSize(string text, string fontFamily, float textSize)
{
var textPaint = new SKPaint(new SKFont(SKTypeface.FromFamilyName(fontFamily), textSize));
SKRect textBounds = new SKRect();
textPaint.MeasureText(text, ref textBounds);
return new SizeF(textBounds.Width, textBounds.Height);
}
}
public class HotkeyButton : Button
{
public static readonly BindableProperty HotkeyTextProperty = BindableProperty.Create(
propertyName: nameof(HotkeyText),
returnType: typeof(string),
declaringType: typeof(MobileEntry),
defaultValue: string.Empty);
public string HotkeyText
{
get { return (string)GetValue(HotkeyTextProperty); }
set { SetValue(HotkeyTextProperty, value); }
}
}

How to set Xamarin.Forms Elements BindableProperties from a Custom Renderer?

I have been trying to set a bindable property value in my Element from my native control through a custom renderer. My native control is a view (painview) where you can draw and I am trying to get the drawing and set it, as a base64 string, to a bindable property Signature in my Element.
This is my Native Control
public class PaintView : View
{
Canvas _drawCanvas;
Bitmap _canvasBitmap;
readonly Paint _paint;
readonly Dictionary<int, MotionEvent.PointerCoords> _coords = new Dictionary<int, MotionEvent.PointerCoords>();
public Bitmap CanvasBitmap { get => _canvasBitmap; private set => _canvasBitmap = value; }
private readonly string TAG = nameof(PaintView);
public event EventHandler OnLineDrawn;
public PaintView(Context context) : base(context, null, 0)
{
_paint = new Paint() { Color = Color.Blue, StrokeWidth = 5f, AntiAlias = true };
_paint.SetStyle(Paint.Style.Stroke);
}
public PaintView(Context context, IAttributeSet attrs) : base(context, attrs) { }
public PaintView(Context context, IAttributeSet attrs, int defStyle) : base(context, attrs, defStyle) { }
protected override void OnSizeChanged(int w, int h, int oldw, int oldh)
{
base.OnSizeChanged(w, h, oldw, oldh);
_canvasBitmap = Bitmap.CreateBitmap(w, h, Bitmap.Config.Argb8888); // full-screen bitmap
_drawCanvas = new Canvas(_canvasBitmap); // the canvas will draw into the bitmap
}
public override bool OnTouchEvent(MotionEvent e)
{
switch (e.ActionMasked)
{
case MotionEventActions.Down:
{
int id = e.GetPointerId(0);
var start = new MotionEvent.PointerCoords();
e.GetPointerCoords(id, start);
_coords.Add(id, start);
return true;
}
case MotionEventActions.PointerDown:
{
int id = e.GetPointerId(e.ActionIndex);
var start = new MotionEvent.PointerCoords();
e.GetPointerCoords(id, start);
_coords.Add(id, start);
return true;
}
case MotionEventActions.Move:
{
for (int index = 0; index < e.PointerCount; index++)
{
var id = e.GetPointerId(index);
float x = e.GetX(index);
float y = e.GetY(index);
_drawCanvas.DrawLine(_coords[id].X, _coords[id].Y, x, y, _paint);
_coords[id].X = x;
_coords[id].Y = y;
OnLineDrawn?.Invoke(this, EventArgs.Empty);
}
Invalidate();
return true;
}
case MotionEventActions.PointerUp:
{
int id = e.GetPointerId(e.ActionIndex);
_coords.Remove(id);
return true;
}
case MotionEventActions.Up:
{
int id = e.GetPointerId(0);
_coords.Remove(id);
return true;
}
default:
return false;
}
}
protected override void OnDraw(Canvas canvas)
{
// Copy the off-screen canvas data onto the View from it's associated Bitmap (which stores the actual drawn data)
canvas.DrawBitmap(_canvasBitmap, 0, 0, null);
}
public void Clear()
{
_drawCanvas.DrawColor(Color.Black, PorterDuff.Mode.Clear); // Paint the off-screen buffer black
Invalidate(); // Call Invalidate to redraw the view
}
public void SetInkColor(Color color)
{
_paint.Color = color;
}
}
The property PaintView._canvasBitmap is the one I want to be set in my Xamarin.Form Element through my custom renderer.
This is my Custom Renderer
public class SketchViewRenderer : ViewRenderer<SketchView, PaintView>
{
public SketchViewRenderer(Context context) : base(context) { }
protected override void OnElementChanged(ElementChangedEventArgs<SketchView> e)
{
if (Control == null)
{
var paintView = new PaintView(Context);
paintView.SetInkColor(Element.InkColor.ToAndroid());
SetNativeControl(new PaintView(Context));
MessagingCenter.Subscribe<SketchView>(this, nameof(SketchView.OnClear), OnMessageClear);
Control.OnLineDrawn += PaintViewLineDrawn;
}
}
private void PaintViewLineDrawn(object sender, EventArgs e)
{
var sketchCrl = (ISketchViewController)Element;
if (sketchCrl == null) return;
try
{
Element.SetValueFromRenderer(SketchView.SignatureProperty, Utils.Utils.BitmapToBase64(Control.CanvasBitmap));
sketchCrl.SendSketchUpdated(Utils.Utils.BitmapToBase64(Control.CanvasBitmap));
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
}
protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
base.OnElementPropertyChanged(sender, e);
if (e.PropertyName == SketchView.InkColorProperty.PropertyName)
{
Control.SetInkColor(Element.InkColor.ToAndroid());
}
if (e.PropertyName == SketchView.ClearProperty.PropertyName)
{
if (Element.Clear) OnMessageClear(Element);
}
}
private void OnMessageClear(SketchView sender)
{
if (sender == Element) Control.Clear();
}
protected override void Dispose(bool disposing)
{
if (disposing)
{
MessagingCenter.Unsubscribe<SketchView>(this, nameof(SketchView.OnClear));
Control.OnLineDrawn -= PaintViewLineDrawn;
}
base.Dispose(disposing);
}
}
I have tried changing my Element.Signature property through the SketchViewRenderer.PaintViewLineDrawn(...) method without success. This has been prove when debugging my view model where the property has not been set as expected.
My Xamarin.Forms Element looks as follow
public class SketchView : View, IDoubleTappedController, ISketchViewController
{
public static readonly BindableProperty SignatureProperty = BindableProperty.Create(nameof(Signature), typeof(string), typeof(SketchView), null, defaultBindingMode: BindingMode.TwoWay);
public string Signature
{
get => (string)GetValue(SignatureProperty);
set => SetValue(SignatureProperty, value);
}
public static readonly BindableProperty MultiTouchEnabledProperty = BindableProperty.Create(nameof(MultiTouchEnabled), typeof(bool), typeof(SketchView), false);
public bool MultiTouchEnabled
{
get => (bool)GetValue(MultiTouchEnabledProperty);
set => SetValue(MultiTouchEnabledProperty, value);
}
public static readonly BindableProperty InkColorProperty = BindableProperty.Create(nameof(InkColor), typeof(Xamarin.Forms.Color), typeof(SketchView), Xamarin.Forms.Color.Azure);
public Xamarin.Forms.Color InkColor
{
get => (Xamarin.Forms.Color)GetValue(InkColorProperty);
set => SetValue(InkColorProperty, value);
}
public static readonly BindableProperty ClearProperty = BindableProperty.Create(nameof(Clear), typeof(bool), typeof(SketchView), false, defaultBindingMode: BindingMode.TwoWay);
public bool Clear
{
get => (bool)GetValue(ClearProperty);
set
{
SetValue(ClearProperty, value);
if (value) { OnClear(); }
}
}
public void OnClear()
{
MessagingCenter.Send(this, nameof(OnClear));
}
public void SetSignature(string signature)
{
Signature = signature;
}
void IDoubleTappedController.DoubleTapped()
{
throw new NotImplementedException();
}
void ISketchViewController.SendSketchUpdated(string signature)
{
Clear = false;
Signature = signature;
}
}
I have also tried using the SetValueFromRenderer() method from my Custom renderer, again, without success.
May you suggest to me what is the way to set an Element value from a Custom Renderer?
Thanks and kind regards,
Temo

The problem was that the field in my view model was set to null when comparing it with the value. Then throwing a TargetException letting the source buggy unable to be updated by the target.
public bool SetProperty<T>(ref T field, T value, [CallerMemberName] string propertyName = default)
{
if (value == null) return false;
if (field != null && field.Equals(value)) return false;
field = value;
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
return true;
}
Now, I make sure the field is not null before using the Equals operator.

Android - Turn switch "On" on ListView item click

I have a custom listview in my C# Android app, each row contains a textview, ImageView and a switch. When a Listview item is clicked, I want to turn the row's item switch on.
MainActivity:
List<TableList> list = = new List<TableList>();
list.Add(new TableList("Germany"));
list.Add(new TableList("France"));
list.Add(new TableList("Finland"));
listView.ItemClick += delegate (object sender, AdapterView.ItemClickEventArgs e)
{
string selected = t.Name;
if (selected == "France")
{
// Turn the proper switch for France row ON
}
};
ListAdapter and ListClass for the Listview:
public class ListAdapter : BaseAdapter<TableList>
{
List<TableList> items;
Activity context;
public ListAdapter(Activity context, List<TableList> items)
: base()
{
this.context = context;
this.items = items;
}
public override long GetItemId(int position)
{
return position;
}
public override TableList this[int position]
{
get { return items[position]; }
}
public override int Count
{
get { return items.Count; }
}
public override View GetView(int position, View convertView, ViewGroup parent)
{
var item = items[position];
View view = convertView;
if (view == null) // no view to re-use, create new
view = context.LayoutInflater.Inflate(Resource.Layout.CoinList, null);
view.FindViewById<TextView>(Resource.Id.CoinName).Text = item.Name;
view.FindViewById<ImageView>(Resource.Id.imageView1).SetImageResource(Resource.Drawable.n);
If item is clicked set it on
{
view.FindViewById<Switch>(Resource.Id.switch).SetOn
}
else
{
view.FindViewById<Switch>(Resource.Id.switch).SetOf
}
return view;
}
}
public class TableList
{
public string Name;
public TableList(string Name)
{
this.Name = Name;
}
}
I don't know where I should set the Switch ON (in the listView.ItemClick event or in the ListAdapter) and I don't know how to set it to ON. Please help me to do so.

Here is my demo.
You can choose one to achieve your goal. I will show you how to do this by ItemClick event:
When a Listview item is clicked, I want to turn the row's item switch on.
Because, Switch will grab the focus from ViewGroup. So, I remove the focus from Switch in the MyAdapter:
holder.ms.Focusable = false;//ms is Switch
Now, this is my ItemClick event( turn switch on while click the item):
private void MListView_ItemClick(object sender, AdapterView.ItemClickEventArgs e)
{
var ll = e.View as LinearLayout;
var sw = ll.GetChildAt(1) as Switch;
if (sw.Checked)
{
sw.Checked = false;
adapter.changeState((int)sw.Tag,false);
}
else
{
sw.Checked = true;
adapter.changeState((int)sw.Tag, true);
}
}
As we all know, ListView has reuse problem, so, I add a bool property to control the Switch's state:
public class MyData:Java.Lang.Object {
public MyData(string p,bool b) {
this.position = p;
this.isCheck = b;
}
public string position { get; set; }
public bool isCheck { get; set; }
}
Below is changeState method:
internal void changeState(int position, bool v)
{
mitems[position].isCheck = v;
this.NotifyDataSetChanged();
}
And this is CheckedChange event:
private void Ms_CheckedChange(object sender, CompoundButton.CheckedChangeEventArgs e)
{
var sm = sender as Switch;
Log.Error("Ms_CheckedChange", (int)sm.Tag+"");
if (e.IsChecked&&!mitems[(int)sm.Tag].isCheck)
{
mitems[(int)sm.Tag].isCheck = true;
this.NotifyDataSetChanged();
}
else if(!e.IsChecked&& mitems[(int)sm.Tag].isCheck)
{
mitems[(int)sm.Tag].isCheck = false;
this.NotifyDataSetChanged();
}
}

OnScrollChanged doesn't get the RecyclerView parameters

I'm trying to implement this code here in my project:
The differences are that instead of a ScrollView I'm using a RecyclerView and that instead of having my RecyclerView directly in the Activity I have inside a fragment that sets the listener I need.
The problem is that while the OnScrollChanged(int l, int t, int oldl, int oldt) gets actually called everytime I scroll, the parameters it obtains are always 0 and I don't understand why, so ScrollChangedTarget doesn't work as intended.
This is the custom RecyclerView:
public class NotifyingScrollRecyclerView : RecyclerView
{
private Activity activity;
private View headerView;
private View footerView;
public delegate void ScrollChangedHandler(int l, int t, int oldl, int oldt, EventArgs e);
public event ScrollChangedHandler scrollChanged;
public EventArgs e = null;
//Enabling all required constructors
public NotifyingScrollRecyclerView(Context context) : base(context)
{
}
public NotifyingScrollRecyclerView(Context context, IAttributeSet attrs) : base(context, attrs)
{
}
public NotifyingScrollRecyclerView(IntPtr ptr, JniHandleOwnership ownership) : base(ptr, ownership)
{
}
public NotifyingScrollRecyclerView(Context context, IAttributeSet attrs, int defStyle) : base(context, attrs, defStyle)
{
}
//This method attribute allows us to register the inbuilt OnScrollChanged event that fires when scrolling a ScrollView
[Android.Runtime.Register("onScrollChanged", "(IIII)V", "GetOnScrollChanged_IIIIHandler")]
protected override void OnScrollChanged(int l, int t, int oldl, int oldt)
{
base.OnScrollChanged(l, t, oldl, oldt);
scrollChanged(l, t, oldl, oldt, e);
}
}
//Set an event listener
public class ScrollViewChangedListener
{
private Activity activity;
private NotifyingScrollRecyclerView scrollView;
private Android.Support.V7.App.ActionBar actionBar;
private Drawable actionBarDrawable;
be changed
public ScrollViewChangedListener(Activity a, NotifyingScrollRecyclerView n)
{
n.scrollChanged += ScrollChangedTarget;
this.activity = a;
this.scrollView = n;
this.actionBar = ((UserPageActivity)a).SupportActionBar;
this.actionBarDrawable = a.GetDrawable(Resource.Drawable.actionbar_background);
this.actionBarDrawable.SetAlpha(0);
}
//Handle the changing of the scroll
public void ScrollChangedTarget(int l, int t, int oldl, int oldt, EventArgs e)
{
//You set the View you want to be your header as a header height, and then get it's height
int headerHeight = activity.FindViewById<ImageView>(Resource.Id.profilebanner).Height -
this.actionBar.Height;
float ratio = (float)Math.Min(Math.Max(t, 0), headerHeight) / headerHeight;
int newAlpha = (int)(ratio * 255);
this.actionBarDrawable.SetAlpha(newAlpha);
this.actionBar.SetBackgroundDrawable(this.actionBarDrawable);
}
}
This is the Activity which calls the fragment (it doesn't do anything in particular aside calling the fragment in this case):
[Activity(Label = "UserPageActivity")]
public class UserPageActivity : BaseActivity
{
protected override int LayoutResource => Resource.Layout.activity_user_page;
UserViewModel viewModel;
TextView username;
TextView usernameToolbar;
Button followButton;
ViewPager pager;
UserTabsAdapter adapter;
bool IsLoggedUser;
protected override void OnCreate(Bundle savedInstanceState)
{
IsLoggedUser = Intent.GetStringExtra("userId").Equals(LoginController.GetInstance().CurrentUser.Email);
base.OnCreate(savedInstanceState);
viewModel = new UserViewModel();
viewModel.UserLoaded += new UserViewModel.UserLoadedHandler(OnUserLoaded);
viewModel.LoadUserCommand.Execute(Intent.GetStringExtra("userId"));
username = FindViewById<TextView>(Resource.Id.profilename);
usernameToolbar = FindViewById<TextView>(Resource.Id.usernamePage);
followButton = FindViewById<Button>(Resource.Id.followButton);
username.Text = Intent.GetStringExtra("username");
usernameToolbar.Text = Intent.GetStringExtra("username");
adapter = new UserTabsAdapter(this, SupportFragmentManager);
pager = FindViewById<ViewPager>(Resource.Id.user_viewpager);
var tabs = FindViewById<TabLayout>(Resource.Id.tabs);
pager.Adapter = adapter;
tabs.SetupWithViewPager(pager);
pager.OffscreenPageLimit = 5;
pager.PageSelected += (sender, args) =>
{
var fragment = adapter.InstantiateItem(pager, args.Position) as IFragmentVisible;
fragment?.BecameVisible();
};
}
private void OnUserLoaded(bool loaded)
{
}
protected override void OnStart()
{
base.OnStart();
if (IsLoggedUser)
{
followButton.Visibility = ViewStates.Gone;
}
else
{
bool following;
if (LoginController.GetInstance().CurrentUser.FollowsUsers.ContainsKey(Intent.GetStringExtra("userId")))
{
followButton.Text = "Unfollow";
following = true;
}
else
{
followButton.Text = "Follow";
following = false;
}
followButton.Click += (object sender, EventArgs e) =>
{
followButton.Enabled = false;
if (following)
{
UserService service = ServiceLocator.Instance.Get<UserService>();
service.SetUser(LoginController.GetInstance().CurrentUser);
service.RemoveFollowsUserCommand.Execute(viewModel.LoadedUser.Email);
service.SetUser(viewModel.LoadedUser);
service.RemoveFollowedByUserCommand.Execute(LoginController.GetInstance().CurrentUser.Email);
followButton.Text = "Follow";
following = false;
}
else
{
UserService service = ServiceLocator.Instance.Get<UserService>();
service.SetUser(LoginController.GetInstance().CurrentUser);
service.AddFollowsUserCommand.Execute(viewModel.LoadedUser);
service.SetUser(viewModel.LoadedUser);
service.AddFollowedByUserCommand.Execute(LoginController.GetInstance().CurrentUser);
followButton.Text = "Unfollow";
following = true;
}
followButton.Enabled = true;
};
}
}
}
class UserTabsAdapter : FragmentStatePagerAdapter
{
string[] titles;
public override int Count => titles.Length;
public UserTabsAdapter(Context context, Android.Support.V4.App.FragmentManager fm) : base(fm)
{
titles = context.Resources.GetTextArray(Resource.Array.user_sections);
}
public override Java.Lang.ICharSequence GetPageTitleFormatted(int position) =>
new Java.Lang.String(titles[position]);
public override Android.Support.V4.App.Fragment GetItem(int position)
{
switch (position)
{
case 0: return UserContestsFragment.NewInstance();
case 1: return UserPartecipationsFragment.NewInstance();
case 2: return GlobalContestFragment.NewInstance();
case 3: return MessagesFragment.NewInstance();
}
return null;
}
public override int GetItemPosition(Java.Lang.Object frag) => PositionNone;
}
This is the fragment which setups the listener for the recyclerview:
public class UserContestsFragment : AbstractRefresherFadingToolbarFragment<Contest>
{
public static UserContestsFragment NewInstance() =>
new UserContestsFragment { Arguments = new Bundle() };
public override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
}
public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
ContestViewModel viewModel = new ContestViewModel();
base.ViewModel = viewModel;
base.LoadItemsCommand = viewModel.LoadAllByCreatorUserCommand;
base.param = Activity.Intent.GetStringExtra("userId");
base.adapter = new ContestsAdapter(Activity, viewModel);
var view = base.OnCreateView(inflater, container, savedInstanceState);
ScrollViewChangedListener listener = new ScrollViewChangedListener(Activity, recyclerView);
return view;
}
And this is the abstract fragment needed by that fragment which is in charge of setting up the layout:
public abstract class AbstractRefresherFadingToolbarFragment<T> : Android.Support.V4.App.Fragment, IFragmentVisible
{
public ICollectionViewModel<T> ViewModel;
public ICommand LoadItemsCommand;
public object param; //parametro per il LoadItemsCommand
public ItemsAdapter<T> adapter;
public SwipeRefreshLayout refresher;
public ProgressBar progress;
public NotifyingScrollRecyclerView recyclerView;
//LruCache cache = new LruCache((int)(Runtime.GetRuntime().MaxMemory() / 4));
public override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
}
public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
View view = inflater.Inflate(Resource.Layout.fragment_fading_toolbar, container, false);
recyclerView = view.FindViewById<NotifyingScrollRecyclerView>(Resource.Id.recyclerView);
//ScrollViewChangedListener listener = new ScrollViewChangedListener((UserPageActivity)Activity, recyclerView);
//adapter.cache = cache;
recyclerView.HasFixedSize = true;
recyclerView.SetAdapter(adapter);
recyclerView.SetItemViewCacheSize(4);
//recyclerView.ChildViewAttachedToWindow += new EventHandler<RecyclerView.ChildViewAttachedToWindowEventArgs>(OnChildViewAttached);
//recyclerView.ChildViewDetachedFromWindow += new EventHandler<RecyclerView.ChildViewDetachedFromWindowEventArgs>(OnChildViewDetached);
refresher = view.FindViewById<SwipeRefreshLayout>(Resource.Id.refresher);
refresher.SetColorSchemeColors(Resource.Color.accent);
progress = view.FindViewById<ProgressBar>(Resource.Id.progressbar_loading);
progress.Visibility = ViewStates.Gone;
return view;
}
}

I didn't read your entire code but I looked at the site you linked in your question. The functionality of the hidden action bar you want to use is handled by CollapsingToolbarLayout in the support library. To know how to use it, go to Cheesesquare. It is a complete example of the support library widgets and can be built and run without any changes.
Edit:
RecyclerView has a method named AddOnScrollListener. Use it instead of the OnScrollChanged. If you use an inherited class from RecyclerView, you can call it in all of the constructors of that class.

OnClickListeners for Recyclerviews -Xamarin.Droid

I have tried to look out for an answer to the behavior of my views but I seem not find any question or solution related to it. My recycler views seemed to be set up well. I just realized that my app is not responding in the right way to the OnClickListeners.
I have set up toasts in my adapter for the recycler view click events. When i have 10 views. When i click on a view, it gives a text of another view. It seems it randomly gives me the text of another view amongst the 9 remaining views. What could be the cause of this?
Activity
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
FrameLayout content = (FrameLayout)FindViewById(Resource.Id.content_frame);
LayoutInflater.Inflate(Resource.Layout.Main, content);
setUpRecyclerView();
}
public void setUpRecyclerView(){
rv = FindViewById<RecyclerView>(Resource.Id.recyclerView);
LinearLayoutManager layoutManager = new LinearLayoutManager(this);
layoutManager.Orientation = LinearLayoutManager.Vertical;
layoutManager.ReverseLayout = true;
layoutManager.StackFromEnd = true;
rv.HasFixedSize = true;
rv.SetLayoutManager(layoutManager);
}
Adapter
public class FeedViewHolder : RecyclerView.ViewHolder, View.IOnClickListener, View.IOnLongClickListener
{
public FeedViewHolder(View itemView):base(itemView)
{
//binding of variables here
itemView.SetOnClickListener(this);
itemView.SetOnLongClickListener(this);
}
public void OnClick(View v)
{
itemClickListener.OnClick(v, AdapterPosition, false);
}
public bool OnLongClick(View v)
{
itemClickListener.OnClick(v, AdapterPosition, true);
return true;
}
public class FeedAdapter : RecyclerView.Adapter, ItemClickListener
{
public FeedAdapter(RssObject rssObject, Context mContext)
{
this.mContext = mContext;
this.inflater = LayoutInflater.From(mContext);
activity = (MainActivity)mContext;
}
public override void OnBindViewHolder(RecyclerView.ViewHolder holder, int position)
{
hold = holder as FeedViewHolder;
//binding
hold.itemClickListener = this;
}
public void OnClick(View view, int position, bool isLongClick)
{
Toast.MakeText(activity, "Main text : " + hold.txtContent.Text, ToastLength.Long).Show();
}
public override int ItemCount
{
get { return rssObject.items.Count; }
}
}
}
}