WPF图形解锁控件ScreenUnLock使用详解

ScreenUnLock 与智能手机上的图案解锁功能一样。通过绘制图形达到解锁或记忆图形的目的。

本人突发奇想，把手机上的图形解锁功能移植到WPF中。也应用到了公司的项目中。

在创建ScreenUnLock之前，先来分析一下图形解锁的实现思路。

1.创建九宫格原点(或更多格子)，每个点定义一个坐标值

2.提供图形解锁相关扩展属性和事件，方便调用者定义。比如：点和线的颜色(Color)，操作模式(Check|Remember)，验证正确的颜色(RightColor), 验证失败的颜色(ErrorColor), 解锁事件 OnCheckedPoint，记忆事件 OnRememberPoint 等;

3.定义MouseMove事件监听画线行为。 画线部分也是本文的核心。在画线过程中。程序需判断，线条从哪个点开始绘制，经过了哪个点(排除已经记录的点)。是否完成了绘制等等。

4.画线完成，根据操作模式处理画线完成行为。并调用相关自定义事件

大致思路如上，下面开始一步一步编写ScreenUnLock吧

创建ScreenUnLock

public partial class ScreenUnlock : UserControl

定义相关属性

/// <summary>
  /// 验证正确的颜色
  /// </summary>
  private SolidColorBrush rightColor;

  /// <summary>
  /// 验证失败的颜色
  /// </summary>
  private SolidColorBrush errorColor;

  /// <summary>
  /// 图案是否在检查中
  /// </summary>
  private bool isChecking;

  public static readonly DependencyProperty PointArrayProperty = DependencyProperty.Register("PointArray", typeof(IList<string>), typeof(ScreenUnlock));
  /// <summary>
  /// 记忆的坐标点
  /// </summary>
  public IList<string> PointArray
  {
   get { return GetValue(PointArrayProperty) as IList<string>; }
   set { SetValue(PointArrayProperty, value); }
  }

  /// <summary>
  /// 当前坐标点集合
  /// </summary>
  private IList<string> currentPointArray;

  /// <summary>
  /// 当前线集合
  /// </summary>
  private IList<Line> currentLineList;

  /// <summary>
  /// 点集合
  /// </summary>
  private IList<Ellipse> ellipseList;

  /// <summary>
  /// 当前正在绘制的线
  /// </summary>
  private Line currentLine;

  public static readonly DependencyProperty OperationPorperty = DependencyProperty.Register("Operation", typeof(ScreenUnLockOperationType), typeof(ScreenUnlock), new FrameworkPropertyMetadata(ScreenUnLockOperationType.Remember));
  /// <summary>
  /// 操作类型
  /// </summary>
  public ScreenUnLockOperationType Operation
  {
   get { return (ScreenUnLockOperationType)GetValue(OperationPorperty); }
   set { SetValue(OperationPorperty, value); }
  }

  public static readonly DependencyProperty PointSizeProperty = DependencyProperty.Register("PointSize", typeof(double), typeof(ScreenUnlock), new FrameworkPropertyMetadata(15.0));
  /// <summary>
  /// 坐标点大小
  /// </summary>
  public double PointSize
  {
   get { return Convert.ToDouble(GetValue(PointSizeProperty)); }
   set { SetValue(PointSizeProperty, value); }
  }

  public static readonly DependencyProperty ColorProperty = DependencyProperty.Register("Color", typeof(SolidColorBrush), typeof(ScreenUnlock), new FrameworkPropertyMetadata(new SolidColorBrush(Colors.White), new PropertyChangedCallback((s, e) =>
  {
   (s as ScreenUnlock).Refresh();
  })));

  /// <summary>
  /// 坐标点及线条颜色
  /// </summary>
  public SolidColorBrush Color
  {
   get { return GetValue(ColorProperty) as SolidColorBrush; }
   set { SetValue(ColorProperty, value); }
  }

 　　　　/// <summary>
 　　　　/// 操作类型
 　　　　/// </summary>
 　　　　public enum ScreenUnLockOperationType
 　　　　{
  　　　　Remember = 0, Check = 1
 　　　　}

初始化ScreenUnLock

public ScreenUnlock()
  {
   InitializeComponent();
   this.Loaded += ScreenUnlock_Loaded;
   this.Unloaded += ScreenUnlock_Unloaded;
   this.MouseMove += ScreenUnlock_MouseMove; //监听绘制事件
  }
 private void ScreenUnlock_Loaded(object sender, RoutedEventArgs e)
  {
   isChecking = false;
   rightColor = new SolidColorBrush(Colors.Green);
   errorColor = new SolidColorBrush(Colors.Red);
   currentPointArray = new List<string>();
   currentLineList = new List<Line>();
   ellipseList = new List<Ellipse>();
   CreatePoint();
  }

  private void ScreenUnlock_Unloaded(object sender, RoutedEventArgs e)
  {
   rightColor = null;
   errorColor = null;
   if (currentPointArray != null)
    this.currentPointArray.Clear();
   if (currentLineList != null)
    this.currentLineList.Clear();
   if (ellipseList != null)
    ellipseList.Clear();
   this.canvasRoot.Children.Clear();
  }

创建点

/// <summary>
  /// 创建点
  /// </summary>
  private void CreatePoint()
  {
   canvasRoot.Children.Clear();
   int row = 3, column = 3; //三行三列，九宫格
   double oneColumnWidth = (this.ActualWidth == 0 ? this.Width : this.ActualWidth) / 3; //单列的宽度
   double oneRowHeight = (this.ActualHeight == 0 ? this.Height : this.ActualHeight) / 3; //单列的高度
   double leftDistance = (oneColumnWidth - PointSize) / 2; //单列左边距
   double topDistance = (oneRowHeight - PointSize) / 2; //单列上边距
   for (var i = 0; i < row; i++)
   {
    for (var j = 0; j < column; j++)
    {
     Ellipse ellipse = new Ellipse()
     {
      Width = PointSize,
      Height = PointSize,
      Fill = Color,
      Tag = string.Format("{0}{1}", i, j)
     };
     Canvas.SetLeft(ellipse, j * oneColumnWidth + leftDistance);
     Canvas.SetTop(ellipse, i * oneRowHeight + topDistance);
     canvasRoot.Children.Add(ellipse);
     ellipseList.Add(ellipse);
    }
   }
  }

创建线

private Line CreateLine()
  {
   Line line = new Line()
   {
    Stroke = Color,
    StrokeThickness = 2
   };
   return line;
  }

点和线都创建都定义好了，可以开始监听绘制事件了

private void ScreenUnlock_MouseMove(object sender, System.Windows.Input.MouseEventArgs e)
  {
   if (isChecking) //如果图形正在检查中，不响应后续处理
    return;
   if (e.LeftButton == System.Windows.Input.MouseButtonState.Pressed)
   {
    var point = e.GetPosition(this);
    HitTestResult result = VisualTreeHelper.HitTest(this, point);
    Ellipse ellipse = result.VisualHit as Ellipse;
    if (ellipse != null)
    {
     if (currentLine == null)
     {
      //从头开始绘制
      currentLine = CreateLine();
      var ellipseCenterPoint = GetCenterPoint(ellipse);
      currentLine.X1 = currentLine.X2 = ellipseCenterPoint.X;
      currentLine.Y1 = currentLine.Y2 = ellipseCenterPoint.Y;

      currentPointArray.Add(ellipse.Tag.ToString());
      Console.WriteLine(string.Join(",", currentPointArray));
      currentLineList.Add(currentLine);
      canvasRoot.Children.Add(currentLine);
     }
     else
     {
      //遇到下一个点，排除已经经过的点
      if (currentPointArray.Contains(ellipse.Tag.ToString()))
       return;
      OnAfterByPoint(ellipse);
     }
    }
    else if (currentLine != null)
    {
     //绘制过程中
     currentLine.X2 = point.X;
     currentLine.Y2 = point.Y;

     //判断当前Line是否经过点
     ellipse = IsOnLine();
     if (ellipse != null)
      OnAfterByPoint(ellipse);
    }
   }
   else
   {
    if (currentPointArray.Count == 0)
     return;
    isChecking = true;
    if (currentLineList.Count + 1 != currentPointArray.Count)
    {
     //最后一条线的终点不在点上
     //两点一线，点的个数-1等于线的条数
     currentLineList.Remove(currentLine); //从已记录的线集合中删除最后一条多余的线
     canvasRoot.Children.Remove(currentLine); //从界面上删除最后一条多余的线
     currentLine = null;
    }

    if (Operation == ScreenUnLockOperationType.Check)
    {
     Console.WriteLine("playAnimation Check");
     var result = CheckPoint(); //执行图形检查
　　　　　　　　　　　　　 //执行完成动画并触发检查事件
     PlayAnimation(result, () =>
     {
      if (OnCheckedPoint != null)
      {
       this.Dispatcher.BeginInvoke(OnCheckedPoint, this, new CheckPointArgs() { Result = result }); //触发检查完成事件
      }
     });

    }
    else if (Operation == ScreenUnLockOperationType.Remember)
    {
     Console.WriteLine("playAnimation Remember");
     RememberPoint(); //记忆绘制的坐标
     var args = new RememberPointArgs() { PointArray = this.PointArray };
　　　　　　　　　　　　　//执行完成动画并触发记忆事件
     PlayAnimation(true, () =>
     {
      if (OnRememberPoint != null)
      {
       this.Dispatcher.BeginInvoke(OnRememberPoint, this, args); //触发图形记忆事件
      }
     });
    }
   }
  }

判断线是否经过了附近的某个点

/// <summary>
  /// 两点计算一线的长度
  /// </summary>
  /// <param name="pt1"></param>
  /// <param name="pt2"></param>
  /// <returns></returns>
  private double GetLineLength(double x1, double y1, double x2, double y2)
  {
   return Math.Sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2)); //根据两点计算线段长度公式 √((x1-x2)²x(y1-y2)²)
  }

  /// <summary>
  /// 判断线是否经过了某个点
  /// </summary>
  /// <param name="ellipse"></param>
  /// <returns></returns>
  private Ellipse IsOnLine()
  {
   double lineAB = 0; //当前画线的长度
   double lineCA = 0; //当前点和A点的距离
   double lineCB = 0; //当前点和B点的距离
   double dis = 0;
   double deciation = 1; //允许的偏差距离
   lineAB = GetLineLength(currentLine.X1, currentLine.Y1, currentLine.X2, currentLine.Y2); //计算当前画线的长度

   foreach (Ellipse ellipse in ellipseList)
   {
    if (currentPointArray.Contains(ellipse.Tag.ToString())) //排除已经经过的点
     continue;
    var ellipseCenterPoint = GetCenterPoint(ellipse); //取当前点的中心点
    lineCA = GetLineLength(currentLine.X1, currentLine.Y1, ellipseCenterPoint.X, ellipseCenterPoint.Y); //计算当前点到线A端的长度
    lineCB = GetLineLength(currentLine.X2, currentLine.Y2, ellipseCenterPoint.X, ellipseCenterPoint.Y); //计算当前点到线B端的长度
    dis = Math.Abs(lineAB - (lineCA + lineCB)); //线CA的长度+线CB的长度>当前线AB的长度 说明点不在线上
    if (dis <= deciation) //因为绘制的点具有一个宽度和高度，所以需设定一个允许的偏差范围，让线靠近点就命中之（吸附效果）
    {
     return ellipse;
    }
   }
   return null;
  }

检查点是否正确，按数组顺序逐个匹配之

/// <summary>
  /// 检查坐标点是否正确
  /// </summary>
  /// <returns></returns>
  private bool CheckPoint()
  {
　　　　　　　　　//PointArray:正确的坐标值数组
 　　　　　　　 //currentPointArray:当前绘制的坐标值数组
   if (currentPointArray.Count != PointArray.Count)
    return false;
   for (var i = 0; i < currentPointArray.Count; i++)
   {
    if (currentPointArray[i] != PointArray[i])
     return false;
   }
   return true;
  }

记录经过点，并创建一条新的线

/// <summary>
  /// 记录经过的点
  /// </summary>
  /// <param name="ellipse"></param>
  private void OnAfterByPoint(Ellipse ellipse)
  {
   var ellipseCenterPoint = GetCenterPoint(ellipse);
   currentLine.X2 = ellipseCenterPoint.X;
   currentLine.Y2 = ellipseCenterPoint.Y;
   currentLine = CreateLine();
   currentLine.X1 = currentLine.X2 = ellipseCenterPoint.X;
   currentLine.Y1 = currentLine.Y2 = ellipseCenterPoint.Y;
   currentPointArray.Add(ellipse.Tag.ToString());
   Console.WriteLine(string.Join(",", currentPointArray));
   currentLineList.Add(currentLine);
   canvasRoot.Children.Add(currentLine);
  }

/// <summary>
  /// 获取原点的中心点坐标
  /// </summary>
  /// <param name="ellipse"></param>
  /// <returns></returns>
  private Point GetCenterPoint(Ellipse ellipse)
  {
   Point p = new Point(Canvas.GetLeft(ellipse) + ellipse.Width / 2, Canvas.GetTop(ellipse) + ellipse.Height / 2);
   return p;
  }

当绘制完成时，执行完成动画并触发响应模式的事件

/// <summary>
  /// 执行动画
  /// </summary>
  /// <param name="result"></param>
  private void PlayAnimation(bool result, Action callback = null)
  {
   Task.Factory.StartNew(() =>
   {
    this.Dispatcher.Invoke((Action)delegate
    {
     foreach (Line l in currentLineList)
      l.Stroke = result ? rightColor : errorColor;
     foreach (Ellipse e in ellipseList)
      if (currentPointArray.Contains(e.Tag.ToString()))
       e.Fill = result ? rightColor : errorColor;
    });
    Thread.Sleep(1500);
    this.Dispatcher.Invoke((Action)delegate
    {
     foreach (Line l in currentLineList)
      this.canvasRoot.Children.Remove(l);
     foreach (Ellipse e in ellipseList)
      e.Fill = Color;
    });
    currentLine = null;
    this.currentPointArray.Clear();
    this.currentLineList.Clear();
    isChecking = false;
   }).ContinueWith(t =>
   {
    try
    {
     if (callback != null)
      callback();
    }
    catch (Exception ex)
    {
     Console.WriteLine(ex.Message);
    }
    finally
    {
     t.Dispose();
    }
   });
  }

图形解锁的调用

<local:ScreenUnlock Width="500" Height="500"
      PointArray="{Binding PointArray, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
      Operation="Check"> <!--或Remember-->
      <i:Interaction.Triggers>
       <i:EventTrigger EventName="OnCheckedPoint">
        <Custom:EventToCommand Command="{Binding OnCheckedPoint}" PassEventArgsToCommand="True"/>
       </i:EventTrigger>
       <i:EventTrigger EventName="OnRememberPoint">
        <Custom:EventToCommand Command="{Binding OnRememberPoint}" PassEventArgsToCommand="True"/>
       </i:EventTrigger>
      </i:Interaction.Triggers>
     </local:ScreenUnlock>

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