Xamarin 表单在按下时禁用图像按钮，背景不正确

Question

我的 Android 图像按钮背景有问题。我根据按下/释放事件实现了长按图像按钮。第一个问题是当我禁用按钮时发布事件。我通过调用 PropagateUpReleased 解决了这个问题，在 iOS 上这就足够了，但在 Android 上我遇到了问题，当我将按钮设置为再次启用时，我有一个按钮背景，就像它被按下一样：

• ，按钮有深灰色
• 长按向上箭头 ImageButton (XamarinForms) 的最大设置按钮为禁用
• 传播释放按钮
• 释放称为
• 禁用按钮具有浅灰色
• 单击向下箭头，向上箭头设置为启用，背景颜色为深灰色 我的 ImageButtonRenderer 实现：

        public CustomButtonRenderer(Context context) : base(context)
        {
        }

        protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
        {

            base.OnElementPropertyChanged(sender, e);

            if (e.PropertyName == nameof(Button.IsEnabled) && !Element.IsEnabled && Element.IsPressed)
            {
                PropagateRelease();
            }
        }

        public override bool OnTouchEvent(MotionEvent e)
        {
            if (e.Action == MotionEventActions.Cancel)
                PropagateRelease();
            return base.OnTouchEvent(e);
        }

        private void PropagateRelease()
        {
            Element.PropagateUpReleased();
            ((IButtonController)Element).SendReleased();

            Invalidate();
            PostInvalidate();
        }

编辑：

这是我的行为实现：

 public class LongPressBehavior : Behavior<ImageButton>
    {
        private readonly object syncObject = new object();
        private const int DurationStartLongPress = 500;
        private const int DurationNextLongPress = 150;
        private ImageButton button;


        private Timer startTimer;
        private Timer nextTimer;
        private volatile bool isReleased;

        public static readonly BindableProperty CommandProperty = BindableProperty.Create(nameof(Command),
            typeof(ICommand), typeof(LongPressBehavior), default(ICommand));

        public ICommand Command
        {
            get => (ICommand)GetValue(CommandProperty);
            set => SetValue(CommandProperty, value);
        }

        #region Cnt
        public LongPressBehavior()
        {
            isReleased = true;
        }
        #endregion

        #region LifeCycles
        protected override void OnAttachedTo(ImageButton button)
        {
            this.button = button;
            base.OnAttachedTo(button);
            this.BindingContext = button.BindingContext;

            button.Pressed += Button_Pressed;
            button.Released += Button_Released;
        }

        protected override void OnDetachingFrom(ImageButton button)
        {
            base.OnDetachingFrom(button);
            this.BindingContext = null;
            
            button.Pressed -= Button_Pressed;
            button.Released -= Button_Released;
        }
        #endregion

        #region Events
        private void Button_Pressed(object sender, EventArgs e)
        {
            Debug.WriteLine("Pressed...");
            isReleased = false;
            InitializeStartTimer();
        }

        private void Button_Released(object sender, EventArgs e)
        {
            
            Debug.WriteLine("Released...");
            isReleased = true;

            DeInitializeTimer(ref startTimer);
            DeInitializeTimer(ref nextTimer);
        }

        protected virtual void OnLongPressed()
        {
            if (button.Command != null)
            {
                Debug.WriteLine("Longpress execute...");
                button.Command.Execute(null);
            }

            if (nextTimer == null)
                InitializeNextTimer();
        }

        private void Timer_Elapsed(object state)
        {
            if (isReleased)
            {
                return;
            }
            Device.BeginInvokeOnMainThread(OnLongPressed);
        }
        #endregion

        #region Private methods
        private void DeInitializeTimer(ref Timer timer)
        {
            Debug.WriteLine("Dispose timer...");
            lock (syncObject)
            {
                if (timer == null)
                {
                    return;
                }
                timer.Change(Timeout.Infinite, Timeout.Infinite);
                timer.Dispose();
                timer = null;
                Debug.WriteLine("Timer disposed...");
            }
        }

        private void InitializeStartTimer()
        {
            Debug.WriteLine("Initialize start timer...");
            lock (syncObject)
            {
                startTimer = new Timer(Timer_Elapsed, null, DurationStartLongPress, Timeout.Infinite);
            }
        }

        private void InitializeNextTimer()
        {
            Debug.WriteLine("Initialize next timer...");
            lock (syncObject)
            {
                if (startTimer != null)
                    DeInitializeTimer(ref startTimer);
                nextTimer = new Timer(Timer_Elapsed, null, DurationNextLongPress, DurationNextLongPress);
            }
        }
        #endregion
    }

问题场景： 我们有 2 个带有向上和向下箭头的按钮来增加和减少值。我们也有最小值和最大值的限制。按钮为白色。

• 用户触摸按钮
• 按下事件被调用，计时器被初始化
• 我在小于maksimum（执行的命令）时增加值。如果 value 有一个 maxsimum，我将 IsEnabled 设置为 false
• Release 事件不会被调用（即使用户释放按钮），而是我手动调用 PropagateUpReleased Android 上的渲染器
• 按钮是浅灰色
• 触摸向下按钮
• 现在值小于最大值，我将按钮 IsEnabled 设置为 true，按钮背景为深灰色（与我们触摸按钮相同）