用WPF圖形解鎖控件ScreenUnLock的方法

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ScreenUnLock 與智能手機上的圖案解鎖功能一樣。通過繪制圖形達到解鎖或記憶圖形的目的。

本人突發(fā)奇想，把手機上的圖形解鎖功能移植到WPF中。也應用到了公司的項目中。

在創(chuàng)建ScreenUnLock之前，先來分析一下圖形解鎖的實現(xiàn)思路。

1.創(chuàng)建九宮格原點(或更多格子)，每個點定義一個坐標值

2.提供圖形解鎖相關擴展屬性和事件，方便調用者定義。比如：點和線的顏色(Color)，操作模式(Check|Remember)，驗證正確的顏色(RightColor), 驗證失敗的顏色(ErrorColor), 解鎖事件 OnCheckedPoint，記憶事件 OnRememberPoint 等;

3.定義MouseMove事件監(jiān)聽畫線行為。 畫線部分也是本文的核心。在畫線過程中。程序需判斷，線條從哪個點開始繪制，經(jīng)過了哪個點(排除已經(jīng)記錄的點)。是否完成了繪制等等。

4.畫線完成，根據(jù)操作模式處理畫線完成行為。并調用相關自定義事件

大致思路如上，下面開始一步一步編寫ScreenUnLock吧

創(chuàng)建ScreenUnLock

public partial class ScreenUnlock : UserControl

定義相關屬性

/// <summary>
  /// 驗證正確的顏色
  /// </summary>
  private SolidColorBrush rightColor;

  /// <summary>
  /// 驗證失敗的顏色
  /// </summary>
  private SolidColorBrush errorColor;

  /// <summary>
  /// 圖案是否在檢查中
  /// </summary>
  private bool isChecking;

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

  /// <summary>
  /// 當前坐標點集合
  /// </summary>
  private IList<string> currentPointArray;

  /// <summary>
  /// 當前線集合
  /// </summary>
  private IList<Line> currentLineList;

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

  /// <summary>
  /// 當前正在繪制的線
  /// </summary>
  private Line currentLine;

  public static readonly DependencyProperty OperationPorperty = DependencyProperty.Register("Operation", typeof(ScreenUnLockOperationType), typeof(ScreenUnlock), new FrameworkPropertyMetadata(ScreenUnLockOperationType.Remember));
  /// <summary>
  /// 操作類型
  /// </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>
  /// 坐標點大小 
  /// </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>
  /// 坐標點及線條顏色
  /// </summary>
  public SolidColorBrush Color
  {
   get { return GetValue(ColorProperty) as SolidColorBrush; }
   set { SetValue(ColorProperty, value); }
  }

 　　　　/// <summary>
 　　　　/// 操作類型
 　　　　/// </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; //監(jiān)聽繪制事件
  }
 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();
  }

創(chuàng)建點

/// <summary>
  /// 創(chuàng)建點
  /// </summary>
  private void CreatePoint()
  {
   canvasRoot.Children.Clear();
   int row = 3, column = 3; //三行三列，九宮格
   double oneColumnWidth = (this.ActualWidth == 0 ? this.Width : this.ActualWidth) / 3; //單列的寬度
   double oneRowHeight = (this.ActualHeight == 0 ? this.Height : this.ActualHeight) / 3; //單列的高度
   double leftDistance = (oneColumnWidth - PointSize) / 2; //單列左邊距
   double topDistance = (oneRowHeight - PointSize) / 2; //單列上邊距
   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);
    }
   }
  }

創(chuàng)建線

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

點和線都創(chuàng)建都定義好了，可以開始監(jiān)聽繪制事件了

private void ScreenUnlock_MouseMove(object sender, System.Windows.Input.MouseEventArgs e)
  {
   if (isChecking) //如果圖形正在檢查中，不響應后續(xù)處理
    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)
     {
      //從頭開始繪制                  
      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
     {
      //遇到下一個點，排除已經(jīng)經(jīng)過的點
      if (currentPointArray.Contains(ellipse.Tag.ToString()))
       return;
      OnAfterByPoint(ellipse);
     }
    }
    else if (currentLine != null)
    {
     //繪制過程中
     currentLine.X2 = point.X;
     currentLine.Y2 = point.Y;

     //判斷當前Line是否經(jīng)過點
     ellipse = IsOnLine();
     if (ellipse != null)
      OnAfterByPoint(ellipse);
    }
   }
   else
   {
    if (currentPointArray.Count == 0)
     return;
    isChecking = true;
    if (currentLineList.Count + 1 != currentPointArray.Count)
    {
     //最后一條線的終點不在點上
     //兩點一線，點的個數(shù)-1等于線的條數(shù)
     currentLineList.Remove(currentLine); //從已記錄的線集合中刪除最后一條多余的線
     canvasRoot.Children.Remove(currentLine); //從界面上刪除最后一條多余的線
     currentLine = null;
    }

    if (Operation == ScreenUnLockOperationType.Check)
    {
     Console.WriteLine("playAnimation Check");
     var result = CheckPoint(); //執(zhí)行圖形檢查
　　　　　　　　　　　　　 //執(zhí)行完成動畫并觸發(fā)檢查事件
     PlayAnimation(result, () =>
     {
      if (OnCheckedPoint != null)
      {
       this.Dispatcher.BeginInvoke(OnCheckedPoint, this, new CheckPointArgs() { Result = result }); //觸發(fā)檢查完成事件
      }
     });

    }
    else if (Operation == ScreenUnLockOperationType.Remember)
    {
     Console.WriteLine("playAnimation Remember");
     RememberPoint(); //記憶繪制的坐標
     var args = new RememberPointArgs() { PointArray = this.PointArray };
　　　　　　　　　　　　　//執(zhí)行完成動畫并觸發(fā)記憶事件
     PlayAnimation(true, () =>
     {
      if (OnRememberPoint != null)
      {
       this.Dispatcher.BeginInvoke(OnRememberPoint, this, args); //觸發(fā)圖形記憶事件
      }
     });
    }
   }
  }

判斷線是否經(jīng)過了附近的某個點

/// <summary>
  /// 兩點計算一線的長度
  /// </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)); //根據(jù)兩點計算線段長度公式 √((x1-x2)2x(y1-y2)2)
  }

  /// <summary>
  /// 判斷線是否經(jīng)過了某個點
  /// </summary>
  /// <param name="ellipse"></param>
  /// <returns></returns>
  private Ellipse IsOnLine()
  {
   double lineAB = 0; //當前畫線的長度
   double lineCA = 0; //當前點和A點的距離 
   double lineCB = 0; //當前點和B點的距離
   double dis = 0;
   double deciation = 1; //允許的偏差距離
   lineAB = GetLineLength(currentLine.X1, currentLine.Y1, currentLine.X2, currentLine.Y2); //計算當前畫線的長度

   foreach (Ellipse ellipse in ellipseList)
   {
    if (currentPointArray.Contains(ellipse.Tag.ToString())) //排除已經(jīng)經(jīng)過的點
     continue;
    var ellipseCenterPoint = GetCenterPoint(ellipse); //取當前點的中心點
    lineCA = GetLineLength(currentLine.X1, currentLine.Y1, ellipseCenterPoint.X, ellipseCenterPoint.Y); //計算當前點到線A端的長度
    lineCB = GetLineLength(currentLine.X2, currentLine.Y2, ellipseCenterPoint.X, ellipseCenterPoint.Y); //計算當前點到線B端的長度
    dis = Math.Abs(lineAB - (lineCA + lineCB)); //線CA的長度+線CB的長度>當前線AB的長度 說明點不在線上
    if (dis <= deciation) //因為繪制的點具有一個寬度和高度，所以需設定一個允許的偏差范圍，讓線靠近點就命中之（吸附效果）
    {
     return ellipse;
    }
   }
   return null;
  }

檢查點是否正確，按數(shù)組順序逐個匹配之

/// <summary>
  /// 檢查坐標點是否正確
  /// </summary>
  /// <returns></returns>
  private bool CheckPoint()
  { 
　　　　　　　　　//PointArray:正確的坐標值數(shù)組
 　　　　　　　 //currentPointArray:當前繪制的坐標值數(shù)組
   if (currentPointArray.Count != PointArray.Count)
    return false;
   for (var i = 0; i < currentPointArray.Count; i++)
   {
    if (currentPointArray[i] != PointArray[i])
     return false;
   }
   return true;
  }

記錄經(jīng)過點，并創(chuàng)建一條新的線

/// <summary>
  /// 記錄經(jīng)過的點
  /// </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>
  /// 獲取原點的中心點坐標
  /// </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;
  }

當繪制完成時，執(zhí)行完成動畫并觸發(fā)響應模式的事件

/// <summary>
  /// 執(zhí)行動畫
  /// </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();
    }
   });
  }

圖形解鎖的調用

<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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