using System;
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using Android.Views;
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using Android.Content;
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using Android.Widget;
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using Android.Graphics.Drawables;
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using static ViewFlow;
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namespace Shared
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{
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//已经全面检查了代码
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/// <summary>
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/// 位置布局
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/// </summary>
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public class PageLayout : ViewGroup, ViewSwitchListener
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{
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/// <summary>
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/// 视图高度
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/// </summary>
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/// <value>The height.</value>
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public override int Height {
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get {
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return base.Height;
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}
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set {
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base.Height = value;
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if (!IsCanRefresh) {
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return;
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}
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var layoutParameters = realViewGroup.LayoutParameters;
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layoutParameters.Height = Height;
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realViewGroup.LayoutParameters = layoutParameters;
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}
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}
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/// <summary>
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/// 视图宽度
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/// </summary>
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/// <value>The width.</value>
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public override int Width {
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get {
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return base.Width;
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}
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set {
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base.Width = value;
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if (!IsCanRefresh) {
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return;
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}
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var layoutParameters = realViewGroup.LayoutParameters;
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layoutParameters.Width = Width;
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realViewGroup.LayoutParameters = layoutParameters;
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}
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}
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/// <summary>
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/// 页面变化事件
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/// </summary>
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public Action<PageLayout, int> PageChange;
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AndroidLinearLayout androidLinearLayout;
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/// <summary>
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/// 构造函数
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/// </summary>
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public PageLayout ()
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{
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viewGroup = new AndroidFrameLayout (Application.Activity, null);
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realViewGroup = new ViewFlow (Application.Activity, this) { };
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(realViewGroup as ViewFlow).setOnViewSwitchListener (this);
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viewGroup.AddView (realViewGroup);
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androidLinearLayout = new AndroidLinearLayout (Application.Activity, this);
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androidLinearLayout.SetGravity (GravityFlags.Center);
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viewGroup.AddView (androidLinearLayout, new Android.Widget.FrameLayout.LayoutParams (Android.Widget.FrameLayout.LayoutParams.MatchParent, DensityUtil.Dip2Px (30), GravityFlags.Bottom));
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}
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/// <summary>
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/// 是否显示下面一排的点
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/// </summary>
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/// <value><c>true</c> if is show point; otherwise, <c>false</c>.</value>
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public bool IsShowPoint {
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get {
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return androidLinearLayout.Visibility == ViewStates.Visible;
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}
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set {
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androidLinearLayout.Visibility = value ? ViewStates.Visible : ViewStates.Invisible;
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}
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}
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/// <summary>
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/// 是否允许滑动
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/// </summary>
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/// <value><c>true</c> if scroll enabled; otherwise, <c>false</c>.</value>
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public bool ScrollEnabled {
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get {
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return (realViewGroup as ViewFlow).ScrollEnabled;
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}
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set {
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(realViewGroup as ViewFlow).ScrollEnabled = value;
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}
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}
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int pageIndex;
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/// <summary>
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/// 设置或者获取当前的界面索引
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/// </summary>
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/// <value>The index of the page.</value>
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public int PageIndex {
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get {
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return (realViewGroup as ViewFlow).Position;
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}
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set
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{
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if (value < 0 || ChildrenCount < value)
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{
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return;
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}
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int beforePageIndex = pageIndex;
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pageIndex = value;
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if (!IsCanRefresh)
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{
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return;
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}
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(realViewGroup as ViewFlow).SetSelection(value);
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}
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}
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/// <summary>
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/// 增加子控件
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/// </summary>
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/// <param name="view">View.</param>
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public override void AddChidren (View view)
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{
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view.Parent = this;
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viewList.Add (view);
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var button = new Android.Widget.Button (Application.Activity);
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int roundRadius = DensityUtil.Dip2Px (5); // 圆角半径
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var gd = new GradientDrawable ();//创建drawable
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if(viewList.Count==1){
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gd.SetColor(Android.Graphics.Color.GhostWhite);
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}else{
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gd.SetColor(Android.Graphics.Color.Gray);
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}
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gd.SetCornerRadius (roundRadius);
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button.Background = gd;
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var layoutParams = new Android.Widget.LinearLayout.LayoutParams (DensityUtil.Dip2Px (10), DensityUtil.Dip2Px (10));
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layoutParams.RightMargin = DensityUtil.Dip2Px (10);
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androidLinearLayout.AddView (button, layoutParams);
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|
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realViewGroup.AddView (view.AndroidView);
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if (!IsCanRefresh) {
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return;
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}
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if (2 <= viewList.Count) {
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view.X = viewList [viewList.Count - 2].Right;
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}
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view.Refresh ();
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//如果父控件是这种，就在最后补上一个控件
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if (GetType () == typeof (VerticalScrolViewLayout)) {
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int tempHeight = -10;
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foreach (var temp in viewList) {
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tempHeight += temp.Height;
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}
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realViewGroup.AddView (new Android.Widget.LinearLayout (Application.Activity) { Tag = "填充" }, new Android.Views.ViewGroup.LayoutParams (Android.Views.ViewGroup.LayoutParams.MatchParent, tempHeight < realViewGroup.LayoutParameters.Height ? realViewGroup.LayoutParameters.Height - tempHeight : 0));
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}
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if (view is ViewGroup) {
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var tempViewGroup = (ViewGroup)view;
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for (int i = 0; i < tempViewGroup.ChildrenCount; i++) {
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tempViewGroup.GetChildren (i).Refresh ();
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}
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}
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}
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/// <summary>
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/// 移除当前控件
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/// </summary>
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/// <param name="view">View.</param>
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internal override void Remove(View view)
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{
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if (view == null)
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{
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return;
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}
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int index = viewList.FindIndex(obj => obj == view);
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if (index < 0)
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{
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return;
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}
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viewList.Remove(view);
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androidLinearLayout.RemoveViewAt(index);
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realViewGroup.RemoveView(view.AndroidView);
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view.Parent = null;
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//new System.Threading.Thread(() =>
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//{
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// Application.RunOnMainThread(() =>
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// {
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(realViewGroup as ViewFlow).SetSelection(PageIndex);
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// });
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//})
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//{ IsBackground = true }.Start();
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}
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/// <summary>
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/// 移除所有的控件
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/// </summary>
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public override void RemoveAll ()
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{
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while (0 < viewList.Count) {
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GetChildren(0)?.RemoveFromParent();
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}
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androidLinearLayout.RemoveAllViews ();
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(realViewGroup as ViewFlow).SetSelection(0);
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}
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/// <summary>
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/// 根据索引移除控件
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/// </summary>
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/// <param name="index">Index.</param>
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public override void RemoveAt (int index)
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{
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if (viewList.Count - 1 < index || index < 0) {
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return;
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}
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androidLinearLayout.RemoveViewAt (index);
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GetChildren(index)?.RemoveFromParent();
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}
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public void onSwitched (Android.Views.View realView, int pageIndex)
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{
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for (int i = 0; i < androidLinearLayout.ChildCount; i++) {
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var view = androidLinearLayout.GetChildAt (i);
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var gradientDrawable = (GradientDrawable)view.Background;//创建drawable
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if (i == pageIndex) {
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gradientDrawable.SetColor (Android.Graphics.Color.GhostWhite);
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} else {
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gradientDrawable.SetColor (Android.Graphics.Color.Gray);
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}
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view.Background = gradientDrawable;
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}
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if (PageChange != null && 0 <= pageIndex) {
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PageChange (this, pageIndex);
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}
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}
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}
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}
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public class ViewFlow : Android.Widget.FrameLayout
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{
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public bool ScrollEnabled = true;
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static int snapVelocity = 1000;
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static int invalidScreen = -1;
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static int touchStateRest = 0;
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static int touchStateScrolling = 1;
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public int Position
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{
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get
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{
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return position;
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}
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}
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int position;
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Scroller scroller;
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VelocityTracker mVelocityTracker;
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int touchState = touchStateRest;
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float lastMotionX;
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float lastMotionY;
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int mTouchSlop;
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int mMaximumVelocity;
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int mCurrentScreen;
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ViewSwitchListener mViewSwitchListener;
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int mLastScrollDirection;
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int mNextScreen;
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/**
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* Receives call backs when a new {@link View} has been scrolled to.
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*/
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public interface ViewSwitchListener
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{
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/**
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* This method is called when a new View has been scrolled to.
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*
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* @param view
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* the {@link View} currently in focus.
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* @param position
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* The position in the adapter of the {@link View} currently in focus.
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*/
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void onSwitched(View view, int position);
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}
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Shared.PageLayout pageLayout;
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public ViewFlow(Context context, Shared.PageLayout view) : base(context)
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{
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pageLayout = view;
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init();
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}
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void init()
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{
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scroller = new Scroller(Context);
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var configuration = ViewConfiguration.Get(Context);
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//最小的滑动距离
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mTouchSlop = configuration.ScaledTouchSlop;
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mMaximumVelocity = configuration.ScaledMaximumFlingVelocity;
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}
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ViewFlow childViewFlow
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{
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get
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{
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if (0 < ChildCount)
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{
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var viewGroup = GetChildAt(ChildCount - 1);
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}
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return null;
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}
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}
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public override void RequestDisallowInterceptTouchEvent(bool disallowIntercept)
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{
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base.RequestDisallowInterceptTouchEvent(disallowIntercept);
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disallowInterceptTouchEvent = disallowIntercept;
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}
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bool disallowInterceptTouchEvent;
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bool isFirst;
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public override bool OnInterceptTouchEvent(MotionEvent ev)
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{
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if (disallowInterceptTouchEvent||IsDelay)
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{
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return false;
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}
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Shared.HDLUtils.WriteLine($"PageLayout->OnInterceptTouchEvent:{Height} {ev.Action}");
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//如果没有子控件或者不允许滑动就返回，不处理当前事件
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if (ChildCount == 0 || !ScrollEnabled)
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return false;
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if (mVelocityTracker == null)
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{
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//初始化速度检测类
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mVelocityTracker = VelocityTracker.Obtain();
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}
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mVelocityTracker.AddMovement(ev);
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float x = ev.GetX();
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float y = ev.GetY();
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switch (ev.Action)
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{
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//每次点击都执行这里
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case MotionEventActions.Down:
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if (!scroller.IsFinished)
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{
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scroller.AbortAnimation();
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snapToDestination(false);
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}
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//记录点击的最新X坐标
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lastMotionX = x;
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lastMotionY = y;
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touchState = scroller.IsFinished ? touchStateRest : touchStateScrolling;
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break;
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//有子控件时执行这里
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case MotionEventActions.Move:
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var deltaX = (int)(lastMotionX - x);
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var deltaY = (int)(lastMotionY - y);
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//当前滑动是否已经超出了设定值
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var xMoved = Math.Abs(deltaX) > mTouchSlop ;
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if (xMoved && Math.Abs(deltaY) < Math.Abs(deltaX))
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{
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if (!isFirst)
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{
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touchState = touchStateScrolling;
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}
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isFirst = false;
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}
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if (touchState == touchStateScrolling)
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{
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//记录最新的坐标，因为接下来控件已经滑动了
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lastMotionX = x;
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int scrollX = ScrollX;
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//向右滑动
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if (deltaX < 0)
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{
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//之前已经滑动的X轴
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if (scrollX > 0)
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{
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//向右滑动时显示出左边的界面，最低的长度为之前已经滑动的距离
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ScrollBy(Math.Max(-scrollX, deltaX), 0);
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}
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}
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//向左滑动
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else if (deltaX > 0)
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{
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//最小的右边需要滑动的距离
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int availableToScroll = GetChildAt(
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ChildCount - 1).Right
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- PaddingRight - HorizontalFadingEdgeLength
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- scrollX - Width;
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if (availableToScroll > 0)
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{
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ScrollBy(Math.Min(availableToScroll, deltaX), 0);
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}
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}
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//当前事件自己处理了，子控制不需要处理当前这事件
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return true;
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}
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break;
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case MotionEventActions.Up:
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if (touchState == touchStateScrolling)
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{
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mVelocityTracker.ComputeCurrentVelocity(1000, mMaximumVelocity);
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var velocityX = mVelocityTracker.XVelocity;
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if (velocityX > snapVelocity && mCurrentScreen > 0)
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{
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// Fling hard enough to move left
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snapToScreen(mCurrentScreen - 1);
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}
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else if (velocityX < -snapVelocity
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&& mCurrentScreen < ChildCount - 1)
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{
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// Fling hard enough to move right
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snapToScreen(mCurrentScreen + 1);
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}
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else
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{
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snapToDestination();
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}
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if (mVelocityTracker != null)
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{
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mVelocityTracker.Recycle();
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mVelocityTracker = null;
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}
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}
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touchState = touchStateRest;
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break;
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case MotionEventActions.Cancel:
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touchState = touchStateRest;
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break;
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}
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return false;
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}
|
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public bool IsDelay;
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public override bool OnTouchEvent(MotionEvent e)
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{
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if (IsDelay || disallowInterceptTouchEvent)
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{
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return false;
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}
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Shared.HDLUtils.WriteLine($"PageLayout->OnTouchEvent:{Height} {e.Action}");
|
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if (ChildCount == 0 || !ScrollEnabled)
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return false;
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if (mVelocityTracker == null)
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{
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mVelocityTracker = VelocityTracker.Obtain();
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}
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mVelocityTracker.AddMovement(e);
|
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var x = e.GetX();
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var y = e.GetY();
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switch (e.Action)
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{
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case MotionEventActions.Down:
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if (!scroller.IsFinished)
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{
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scroller.AbortAnimation();
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snapToDestination(false);
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}
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lastMotionX = x;
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lastMotionY = y;
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touchState = scroller.IsFinished ? touchStateRest
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: touchStateScrolling;
|
|
break;
|
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case MotionEventActions.Move:
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var deltaX = (int)(lastMotionX - x);
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var deltaY = (int)(lastMotionY - y);
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//当前滑动是否已经超出了设定值
|
var xMoved = Math.Abs(deltaX) > mTouchSlop;
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if (xMoved && Math.Abs(deltaY) < Math.Abs(deltaX))
|
{
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if (!isFirst)
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{
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touchState = touchStateScrolling;
|
}
|
isFirst = false;
|
}
|
|
if (touchState == touchStateScrolling)
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{
|
lastMotionX = x;
|
|
int scrollX = ScrollX;
|
if (deltaX < 0)
|
{
|
if (scrollX > 0)
|
{
|
ScrollBy(Math.Max(-scrollX, deltaX), 0);
|
}
|
}
|
else if (deltaX > 0)
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{
|
int availableToScroll = GetChildAt(
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ChildCount - 1).Right
|
- PaddingRight - HorizontalFadingEdgeLength
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- scrollX - screenWidth;
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if (availableToScroll > 0)
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{
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ScrollBy(Math.Min(availableToScroll, deltaX), 0);
|
}
|
}
|
return true;
|
}
|
break;
|
|
case MotionEventActions.Up:
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if (touchState == touchStateScrolling)
|
{
|
mVelocityTracker.ComputeCurrentVelocity(1000, mMaximumVelocity);
|
var velocityX = mVelocityTracker.XVelocity;
|
|
if (velocityX > snapVelocity && mCurrentScreen > 0)
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{
|
// Fling hard enough to move left
|
snapToScreen(mCurrentScreen - 1);
|
}
|
else if (velocityX < -snapVelocity
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&& mCurrentScreen < ChildCount - 1)
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{
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// Fling hard enough to move right
|
snapToScreen(mCurrentScreen + 1);
|
}
|
else
|
{
|
snapToDestination();
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}
|
|
if (mVelocityTracker != null)
|
{
|
mVelocityTracker.Recycle();
|
mVelocityTracker = null;
|
}
|
}
|
|
touchState = touchStateRest;
|
break;
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case MotionEventActions.Cancel:
|
snapToDestination();
|
touchState = touchStateRest;
|
break;
|
}
|
return true;
|
}
|
|
/// <summary>
|
/// 子控件的宽度
|
/// </summary>
|
/// <value>The width of the child.</value>
|
int screenWidth
|
{
|
get
|
{
|
return MeasuredWidth;
|
}
|
}
|
/// <summary>
|
/// 滑动到指定的界面
|
/// </summary>
|
void snapToDestination(bool isDelay=true)
|
{
|
int whichScreen = (ScrollX + (screenWidth / 2)) / screenWidth;
|
|
snapToScreen(whichScreen,isDelay);
|
}
|
/// <summary>
|
/// 滑动到指定界面
|
/// </summary>
|
/// <param name="whichScreen">Which screen.</param>
|
void snapToScreen(int whichScreen,bool isDelay=true)
|
{
|
mLastScrollDirection = whichScreen - mCurrentScreen;
|
if (!scroller.IsFinished)
|
return;
|
|
whichScreen = Math.Max(0, Math.Min(whichScreen, ChildCount - 1));
|
Shared.HDLUtils.WriteLine($"snapToScreen:{whichScreen}");
|
mNextScreen = whichScreen;
|
|
int newX = whichScreen * screenWidth;
|
int delta = newX - ScrollX;
|
scroller.StartScroll(ScrollX, 0, delta, 0, isDelay ? Math.Abs(delta) * 2 : 0);
|
Invalidate();
|
}
|
|
public override void ComputeScroll()
|
{
|
if (scroller.ComputeScrollOffset())
|
{
|
ScrollTo(scroller.CurrX, scroller.CurrY);
|
PostInvalidate();
|
}
|
else if (mNextScreen != invalidScreen)
|
{
|
mCurrentScreen = Math.Max(0, Math.Min(mNextScreen, ChildCount - 1));
|
mNextScreen = invalidScreen;
|
postViewSwitched(mLastScrollDirection);
|
}
|
}
|
|
|
|
|
/**
|
* Scroll to the {@link View} in the view buffer specified by the index.
|
*
|
* @param indexInBuffer
|
* Index of the view in the view buffer.
|
*/
|
void setVisibleView(int indexInBuffer, bool uiThread)
|
{
|
mCurrentScreen = Math.Max(0, Math.Min(indexInBuffer, ChildCount - 1));
|
int dx = (mCurrentScreen * screenWidth) - scroller.CurrX;
|
scroller.StartScroll(scroller.CurrX, scroller.CurrY, dx,0, 0);
|
|
if (dx == 0)
|
OnScrollChanged(scroller.CurrX + dx, scroller.CurrY, scroller.CurrX + dx, scroller.CurrY);
|
|
if (uiThread)
|
Invalidate();
|
else
|
PostInvalidate();
|
}
|
|
/**
|
* Set the listener that will receive notifications every time the {code
|
* ViewFlow} scrolls.
|
*
|
* @param l
|
* the scroll listener
|
*/
|
public void setOnViewSwitchListener(ViewSwitchListener l)
|
{
|
mViewSwitchListener = l;
|
}
|
|
public void SetSelection(int position)
|
{
|
mNextScreen = invalidScreen;
|
scroller.ForceFinished(true);
|
var beforePosition = this.position;
|
position = Math.Max(position, 0);
|
position = Math.Min(position, ChildCount - 1);
|
if (position < 0)
|
{
|
return;
|
}
|
|
var currentView = GetChildAt(position);
|
this.position = position;
|
|
setVisibleView(this.position, true);
|
RequestLayout();
|
|
if (mViewSwitchListener != null && beforePosition != this.position)
|
{
|
mViewSwitchListener.onSwitched(currentView, this.position);
|
}
|
}
|
|
void postViewSwitched(int direction)
|
{
|
if (direction == 0)
|
return;
|
|
var beforePosition = position;
|
|
if (direction > 0)
|
{ // to the right
|
position++;
|
position = Math.Min(position, ChildCount - 1);
|
|
}
|
else
|
{ // to the left
|
position--;
|
position = Math.Max(position, 0);
|
}
|
|
setVisibleView(position, true);
|
RequestLayout();
|
|
if (mViewSwitchListener != null && beforePosition != position)
|
{
|
mViewSwitchListener.onSwitched(GetChildAt(position),position);
|
}
|
}
|
|
bool isHaveSameTypeParent
|
{
|
get
|
{
|
var parent = Parent;
|
while (parent != null)
|
{
|
if (parent is ViewFlow)
|
{
|
return true;
|
}
|
parent = parent.Parent;
|
}
|
return false;
|
}
|
|
}
|
|
public override bool DispatchTouchEvent(MotionEvent e)
|
{
|
//Shared.HDLUtils.WriteLine($"PageLayout->DispatchTouchEvent:{Height} {e.Action}");
|
if(e.Action== MotionEventActions.Down) {
|
//还原中断
|
RequestDisallowInterceptTouchEvent(false);
|
isFirst = true;
|
IsDelay = false;
|
}
|
if (isHaveSameTypeParent && !isScrolledToBottom)
|
{
|
//如果父控件和当前控件一样，并且没有滑动到底也没有da
|
Parent.RequestDisallowInterceptTouchEvent(true);
|
}
|
else
|
{
|
isScrolledToBottom = false;
|
Parent.RequestDisallowInterceptTouchEvent(false);
|
}
|
return base.DispatchTouchEvent(e);
|
}
|
|
private bool isScrolledToTop = true; // 初始化的时候设置一下值
|
private bool isScrolledToBottom;
|
|
protected override void OnOverScrolled(int scrollX, int scrollY, bool clampedX, bool clampedY)
|
{
|
base.OnOverScrolled(scrollX, scrollY, clampedX, clampedY);
|
if (scrollY == 0)
|
{
|
isScrolledToTop = clampedY;
|
isScrolledToBottom = false;
|
}
|
else
|
{
|
isScrolledToTop = false;
|
isScrolledToBottom = clampedY;
|
}
|
|
}
|
|
|
protected override void OnScrollChanged(int l, int t, int oldl, int oldt)
|
{
|
base.OnScrollChanged(l, t, oldl, oldt);
|
if ((int)Android.OS.Build.VERSION.SdkInt < 9)
|
{ // API 9及之后走onOverScrolled方法监听
|
if (ScrollY == 0)
|
{ // 小心踩坑1: 这里不能是getScrollY() <= 0
|
isScrolledToTop = true;
|
isScrolledToBottom = false;
|
}
|
else if (ScrollY + Height - PaddingTop - PaddingBottom == (0 < ChildCount ? GetChildAt(0).Height : Height))
|
{
|
// 小心踩坑2: 这里不能是 >=
|
// 小心踩坑3（可能忽视的细节2）：这里最容易忽视的就是ScrollView上下的padding
|
isScrolledToBottom = true;
|
isScrolledToTop = false;
|
}
|
else
|
{
|
isScrolledToTop = false;
|
isScrolledToBottom = false;
|
}
|
}
|
// 有时候写代码习惯了，为了兼容一些边界奇葩情况，上面的代码就会写成<=,>=的情况，结果就出bug了
|
// 我写的时候写成这样：getScrollY() + getHeight() >= getChildAt(0).getHeight()
|
// 结果发现快滑动到底部但是还没到时，会发现上面的条件成立了，导致判断错误
|
// 原因：getScrollY()值不是绝对靠谱的，它会超过边界值，但是它自己会恢复正确，导致上面的计算条件不成立
|
// 仔细想想也感觉想得通，系统的ScrollView在处理滚动的时候动态计算那个scrollY的时候也会出现超过边界再修正的情况
|
}
|
}
|
