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IlyaLavrov97/BLMMX.cs

Last active March 31, 2021 17:42
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better link movement method xamarin android + url span ellipsize feature + url no underline feature
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BLMMX.cs
using Android.Text.Method;
using System;
using Android.Widget;
using Android.Text;
using Android.Views;
using Android.Text.Style;
using Android.Graphics;
using System.Collections.Generic;
using Android.App;
using Java.Lang;
using Android.Text.Util;
using System.Linq;
namespace TestNamespace
{
public class BetterLinkMovementMethod : LinkMovementMethod
{
#region Fields
private static BetterLinkMovementMethod singleInstance;
private const int LINKIFY_NONE = -2;
private const int MAX_LINK_LENGTH = 30;
private IOnLinkClickListener onLinkClickListener;
private IOnLinkLongClickListener onLinkLongClickListener;
private RectF touchedLineBounds = new RectF();
private ClickableSpan clickableSpanUnderTouchOnActionDown;
private int activeTextViewHashcode;
private LongPressTimer ongoingLongPressTimer;
private bool wasLongPressRegistered;
#endregion
#region Interfaces
public interface IOnLinkClickListener
{
bool OnClick(TextView textView, string url);
}
public interface IOnLinkLongClickListener
{
bool OnLongClick(TextView textView, string url);
}
#endregion
#region Constructor
protected BetterLinkMovementMethod()
{
}
#endregion
#region Private
private void CleanupOnTouchUp(TextView textView)
{
wasLongPressRegistered = false;
clickableSpanUnderTouchOnActionDown = null;
RemoveLongPressCallback(textView);
}
private static void AddLinks(MatchOptions linkifyMask, BetterLinkMovementMethod movementMethod, TextView textView, bool removeUnderline = true)
{
textView.MovementMethod = movementMethod;
SpannableStringBuilder ssb = new SpannableStringBuilder(textView.Text);
global::Android.Text.Util.Linkify.AddLinks(ssb, linkifyMask);
URLSpan[] spans = ssb.GetSpans(0, ssb.Length(), Class.FromType(typeof(URLSpan))).Cast<URLSpan>().ToArray();
foreach (var span in spans)
{
int start = ssb.GetSpanStart(span);
int end = ssb.GetSpanEnd(span);
var flags = ssb.GetSpanFlags(span);
string linkText = ssb.SubSequence(start, end);
if (linkText.Length > MAX_LINK_LENGTH)
{
//1 - Remove the https:// or http:// prefix
if (linkText.ToString().ToLower().StartsWith("https://"))
linkText = linkText.Substring("https://".Length, linkText.Length - "https://".Length);
else if (linkText.ToString().ToLower().StartsWith("http://"))
linkText = linkText.Substring("http://".Length, linkText.Length - "http://".Length);
// 2 - Remove the www. prefix
else if (linkText.ToString().ToLower().StartsWith("www."))
linkText = linkText.Substring("www.".Length, linkText.Length - "www.".Length);
// 3 - Truncate if still longer than MAX_LINK_LENGTH
if (linkText.Length > MAX_LINK_LENGTH && linkifyMask.HasFlag(MatchOptions.WebUrls))
linkText = linkText.Substring(0, MAX_LINK_LENGTH) + "...";
}
// 4 - Replace the text preserving the spans
ssb.Replace(start, end, linkText);
ssb.RemoveSpan(span);
if (removeUnderline)
{
URLSpanNoUnderline s = new URLSpanNoUnderline(span.URL);
ssb.SetSpan(s, start, start + linkText.Length, flags);
}
else
ssb.SetSpan(span, start, start + linkText.Length, flags);
}
textView.SetText(ssb, TextView.BufferType.Spannable);
}
private static void RecursivelyAddLinks(MatchOptions linkifyMask, ViewGroup viewGroup, BetterLinkMovementMethod movementMethod)
{
for (int i = 0; i < viewGroup.ChildCount; i++)
{
View child = viewGroup.GetChildAt(i);
if (child is ViewGroup)
{
// Recursively find child TextViews.
RecursivelyAddLinks(linkifyMask, ((ViewGroup)child), movementMethod);
}
else if (child is TextView textView)
{
AddLinks(linkifyMask, movementMethod, textView);
}
}
}
private void StartTimerForRegisteringLongClick(TextView textView, LongPressTimer.IOnTimerReachedListener longClickListener)
{
ongoingLongPressTimer = new LongPressTimer();
ongoingLongPressTimer.SetOnTimerReachedListener(longClickListener);
textView.PostDelayed(ongoingLongPressTimer, ViewConfiguration.LongPressTimeout);
}
#endregion
#region Protected
protected ClickableSpan FindClickableSpanUnderTouch(TextView textView, ISpannable text, MotionEvent e)
{
// So we need to find the location in text where touch was made, regardless of whether the TextView
// has scrollable text. That is, not the entire text is currently visible.
int touchX = (int)e.GetX();
int touchY = (int)e.GetY();
// Ignore padding.
touchX -= textView.TotalPaddingLeft;
touchY -= textView.TotalPaddingTop;
// Account for scrollable text.
touchX += textView.ScrollX;
touchY += textView.ScrollY;
Layout layout = textView.Layout;
int touchedLine = layout.GetLineForVertical(touchY);
int touchOffset = layout.GetOffsetForHorizontal(touchedLine, touchX);
touchedLineBounds.Left = layout.GetLineLeft(touchedLine);
touchedLineBounds.Top = layout.GetLineTop(touchedLine);
touchedLineBounds.Right = layout.GetLineWidth(touchedLine) + touchedLineBounds.Left;
touchedLineBounds.Bottom = layout.GetLineBottom(touchedLine);
if (touchedLineBounds.Contains(touchX, touchY))
{
// Find a ClickableSpan that lies under the touched area.
Java.Lang.Object[] spans = text.GetSpans(touchOffset, touchOffset, Class.FromType(typeof(ClickableSpan)));
foreach (Java.Lang.Object span in spans)
{
if (span is ClickableSpan)
{
return (ClickableSpan)span;
}
}
// No ClickableSpan found under the touched location.
return null;
}
else
{
// Touch lies outside the line's horizontal bounds where no spans should exist.
return null;
}
}
//Remove the long-press detection timer.
protected void RemoveLongPressCallback(TextView textView)
{
if (ongoingLongPressTimer != null)
{
textView.RemoveCallbacks(ongoingLongPressTimer);
ongoingLongPressTimer = null;
}
}
protected void DispatchUrlClick(TextView textView, ClickableSpan clickableSpan)
{
ClickableSpanWithText clickableSpanWithText = ClickableSpanWithText.OfSpan(textView, clickableSpan);
bool handled = onLinkClickListener != null && onLinkClickListener.OnClick(textView, clickableSpanWithText.Text);
if (!handled)
{
// Let Android handle this click.
clickableSpanWithText.Span.OnClick(textView);
}
}
protected void DispatchUrlLongClick(TextView textView, ClickableSpan clickableSpan)
{
ClickableSpanWithText clickableSpanWithText = ClickableSpanWithText.OfSpan(textView, clickableSpan);
bool handled = onLinkLongClickListener != null && onLinkLongClickListener.OnLongClick(textView, clickableSpanWithText.Text);
if (!handled)
{
// Let Android handle this long click as a short-click.
clickableSpanWithText.Span.OnClick(textView);
}
}
#endregion
#region Public
//Get a static instance of BetterLinkMovementMethod. Do note that registering a click listener on the returned
//instance is not supported because it will potentially be shared on multiple TextViews.
public static BetterLinkMovementMethod GetInstance()
{
if (singleInstance == null)
{
singleInstance = new BetterLinkMovementMethod();
}
return singleInstance;
}
public static BetterLinkMovementMethod NewInstance()
{
return new BetterLinkMovementMethod();
}
public static BetterLinkMovementMethod Linkify(MatchOptions linkifyMask, List<TextView> textViews)
{
BetterLinkMovementMethod movementMethod = NewInstance();
foreach (var textView in textViews)
{
AddLinks(linkifyMask, movementMethod, textView);
}
return movementMethod;
}
public static BetterLinkMovementMethod Linkify(MatchOptions linkifyMask, ViewGroup viewGroup)
{
BetterLinkMovementMethod movementMethod = NewInstance();
RecursivelyAddLinks(linkifyMask, viewGroup, movementMethod);
return movementMethod;
}
public static BetterLinkMovementMethod Linkify(MatchOptions linkifyMask, Activity activity)
{
// Find the layout passed to setContentView().
ViewGroup activityLayout = ((ViewGroup)((ViewGroup)activity.FindViewById(Window.IdAndroidContent)).GetChildAt(0));
BetterLinkMovementMethod movementMethod = NewInstance();
RecursivelyAddLinks(linkifyMask, activityLayout, movementMethod);
return movementMethod;
}
//Set a listener that will get called whenever any link is clicked on the TextView.
public BetterLinkMovementMethod SetOnLinkClickListener(IOnLinkClickListener clickListener)
{
if (this == singleInstance)
{
throw new UnsupportedOperationException("Setting a click listener on the instance returned by getInstance() is not supported to avoid memory " +
"leaks. Please use newInstance() or any of the linkify() methods instead.");
}
this.onLinkClickListener = clickListener;
return this;
}
//Set a listener that will get called whenever any link is clicked on the TextView.
public BetterLinkMovementMethod SetOnLinkLongClickListener(IOnLinkLongClickListener longClickListener)
{
if (this == singleInstance)
{
throw new UnsupportedOperationException("Setting a long-click listener on the instance returned by getInstance() is not supported to avoid " +
"memory leaks. Please use newInstance() or any of the linkify() methods instead.");
}
this.onLinkLongClickListener = longClickListener;
return this;
}
public override bool OnTouchEvent(TextView textView, ISpannable text, MotionEvent e)
{
if (activeTextViewHashcode != textView.GetHashCode())
{
// Bug workaround: TextView stops calling onTouchEvent() once any URL is highlighted.
// A hacky solution is to reset any "autoLink" property set in XML. But we also want
// to do this once per TextView.
activeTextViewHashcode = textView.GetHashCode();
textView.AutoLinkMask = 0;
}
ClickableSpan clickableSpanUnderTouch = FindClickableSpanUnderTouch(textView, text, e);
if (e.Action == MotionEventActions.Down)
{
clickableSpanUnderTouchOnActionDown = clickableSpanUnderTouch;
}
bool touchStartedOverAClickableSpan = clickableSpanUnderTouchOnActionDown != null;
switch (e.Action)
{
case MotionEventActions.Down:
if (touchStartedOverAClickableSpan && onLinkLongClickListener != null)
{
LongPressTimer.IOnTimerReachedListener longClickListener = new CustomTimerReachedListener(() =>
{
wasLongPressRegistered = true;
textView.PerformHapticFeedback(FeedbackConstants.LongPress);
DispatchUrlLongClick(textView, clickableSpanUnderTouch);
});
StartTimerForRegisteringLongClick(textView, longClickListener);
}
return touchStartedOverAClickableSpan;
case MotionEventActions.Up:
// Register a click only if the touch started and ended on the same URL.
if (!wasLongPressRegistered && touchStartedOverAClickableSpan && clickableSpanUnderTouch == clickableSpanUnderTouchOnActionDown)
{
DispatchUrlClick(textView, clickableSpanUnderTouch);
}
CleanupOnTouchUp(textView);
// Consume this event even if we could not find any spans to avoid letting Android handle this event.
// Android's TextView implementation has a bug where links get clicked even when there is no more text
// next to the link and the touch lies outside its bounds in the same direction.
return touchStartedOverAClickableSpan;
case MotionEventActions.Cancel:
CleanupOnTouchUp(textView);
return false;
case MotionEventActions.Move:
// Stop listening for a long-press as soon as the user wanders off to unknown lands.
if (clickableSpanUnderTouch != clickableSpanUnderTouchOnActionDown)
{
RemoveLongPressCallback(textView);
}
return touchStartedOverAClickableSpan;
default:
return false;
}
}
#endregion
#region Support classes
private class LongPressTimer : Java.Lang.Object, IRunnable
{
private IOnTimerReachedListener onTimerReachedListener;
public LongPressTimer()
{
}
public interface IOnTimerReachedListener
{
void OnTimerReached();
}
public void Run()
{
onTimerReachedListener.OnTimerReached();
}
public void SetOnTimerReachedListener(IOnTimerReachedListener listener)
{
onTimerReachedListener = listener;
}
}
private class CustomTimerReachedListener : LongPressTimer.IOnTimerReachedListener
{
public Action Action { get; set; }
public CustomTimerReachedListener(Action action)
{
Action = action;
}
public void OnTimerReached()
{
Action();
}
}
// A wrapper to support all {@link ClickableSpan}s that may or may not provide URLs.
private class ClickableSpanWithText
{
public ClickableSpan Span { get; set; }
public string Text { get; set; }
public ClickableSpanWithText(ClickableSpan span, string text)
{
Span = span;
Text = text;
}
public static ClickableSpanWithText OfSpan(TextView textView, ClickableSpan span)
{
SpannedString s = new SpannedString(textView.Text);
string text;
if (span is URLSpan)
{
text = ((URLSpan)span).URL;
}
else
{
int start = s.GetSpanStart(span);
int end = s.GetSpanEnd(span);
text = s.SubSequence(start, end).ToString();
}
return new ClickableSpanWithText(span, text);
}
}
#endregion
}
}
Raw
BLMMX_ex.cs
namespace TestNamespace
{
public class Example
{
BetterLinkMovementMethod
.Linkify(MatchOptions.All, new List<TextView> { MyTextView })
.SetOnLinkClickListener(new MyClickListener());
BetterLinkMovementMethod
.Linkify(MatchOptions.All, MyView)
.SetOnLinkClickListener(new MyClickListener());
BetterLinkMovementMethod
.Linkify(MatchOptions.All, MyActivity)
.SetOnLinkClickListener(new MyClickListener());
}
}
@DmitriyKirakosyan
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The line

using TORMobile.Droid.Android.Helpers;

is not needed.

@IlyaLavrov97
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Author

The line

using TORMobile.Droid.Android.Helpers;

is not needed.

fixed

@DmitriyKirakosyan
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Here is also an MVVMCross binding:

using System.Collections.Generic;
using Android.Text.Util;
using Android.Widget;
using MvvmCross.Binding;
using MvvmCross.Platforms.Android.Binding.Target;

namespace Epyks.Client.Mobile.Android.Bindings
{
    public class TextWithLinksBinding : MvxAndroidTargetBinding<TextView, string>
    {
        public TextWithLinksBinding(TextView textView) : base(textView)
        {
        }

        public override MvxBindingMode DefaultMode => MvxBindingMode.OneWay;

        protected override void SetValueImpl(TextView target, string value)
        {
            if (!string.IsNullOrWhiteSpace(value))
            {
                target.Text = value;
                BetterLinkMovementMethod.Linkify(MatchOptions.All, new List<TextView> { target });
            }
        }
    }
}

Creating a binding is required because you can't simply apply BetterLinkMovementMethod.Linkify to a TextView which is bound to a ViewModel's property, because the links will be cleared once the text is changed, which is frequently happening with MvxRecyclerView.

@giuseppenovielli
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Thanks you very much!

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