wp7上加速器例子講解（官方demo)

 1.新建項目在 xaml當中添加如下代碼

<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
    <Button Content="Start" Height="72" HorizontalAlignment="Left" Margin="20,10,0,0" Name="startButton" VerticalAlignment="Top" Width="160" Click="startButton_Click"   />
    <Button Content="Stop" Height="72" HorizontalAlignment="Right" Margin="0,10,20,0" Name="stopButton" VerticalAlignment="Top" Width="160" Click="stopButton_Click"    />
    <TextBlock Height="30" HorizontalAlignment="Left"  Margin="20,100,0,0" Name="xTextBlock" Text="X: 1.0" VerticalAlignment="Top" Foreground="Red" FontSize="28" FontWeight="Bold"/>
    <TextBlock Height="30" HorizontalAlignment="Center"  Margin="0,100,0,0" Name="yTextBlock" Text="Y: 1.0" VerticalAlignment="Top" Foreground="Green" FontSize="28" FontWeight="Bold"/>
    <TextBlock Height="30" HorizontalAlignment="Right"  Margin="0,100,20,0" Name="zTextBlock" Text="Z: 1.0" VerticalAlignment="Top"  Foreground="Blue" FontSize="28" FontWeight="Bold"/>
    <Line x:Name="xLine" X1="240" Y1="350" X2="340" Y2="350" Stroke="Red" StrokeThickness="4"></Line>
    <Line x:Name="yLine" X1="240" Y1="350" X2="240" Y2="270" Stroke="Green" StrokeThickness="4"></Line>
    <Line x:Name="zLine" X1="240" Y1="350" X2="190" Y2="400" Stroke="Blue" StrokeThickness="4"></Line>
    <TextBlock Height="30" HorizontalAlignment="Center" Margin="6,571,6,0" Name="statusTextBlock" Text="TextBlock" VerticalAlignment="Top" Width="444" />
</Grid>

打開設計器 會得到如下界面 start 按鈕爲開啓  加速傳感器 , stop 停止加速傳感器

 

3.添加Microsoft.Devices.Sensors 命名空間 到項目

 

4.點擊確定 後打開cs 文件

 

Accelerometer accelerometer; //初始化加速器
      // Constructor
      public MainPage()
      {
          InitializeComponent();
          if (!Accelerometer.IsSupported)   //如果不支持 加速器  界面上的startButton，stopButton 不可用
          {
              statusTextBlock.Text = "device do not support the accelerometer;";
              startButton.IsEnabled = false;
              stopButton.IsEnabled = false;
          }

      }

 

5.添加 startButton 和stopButton 的click事件

 

private void startButton_Click(object sender, RoutedEventArgs e)
    {
        accelerometer = new Accelerometer();
        accelerometer.TimeBetweenUpdates = TimeSpan.FromMilliseconds(20);
        accelerometer.CurrentValueChanged += new EventHandler<SensorReadingEventArgs<AccelerometerReading>>(accelerometer_CurrentValueChanged);
        try
        {
            statusTextBlock.Text = "starting accelerometer";
            accelerometer.Start();
        }
        catch (Exception ex)
        {
            ex.ToString();
            statusTextBlock.Text = "unable start the accelerometer";
        }
    }



    private void stopButton_Click(object sender, RoutedEventArgs e)
    {
        if (accelerometer != null)
        {
            // Stop the accelerometer.
            accelerometer.Stop();
            statusTextBlock.Text = "accelerometer stopped.";
        }
    }
//該方法爲回調方法，通過該方法可以獲取到加速器的x,y,z軸的相關數據
    void accelerometer_CurrentValueChanged(object sender, SensorReadingEventArgs<AccelerometerReading> e)
    {
        // Call UpdateUI on the UI thread and pass the AccelerometerReading.
        Dispatcher.BeginInvoke(() => UpdateUI(e.SensorReading));
    }

6.最後我們把更新UI界面數據的邏輯寫入一個封裝到一個方法裏

 

/// <summary>
       /// 更新ui數據
       /// </summary>
       /// <param name="accelerometerReading"></param>
       private void UpdateUI(AccelerometerReading accelerometerReading)
       {
           statusTextBlock.Text = "getting data";

           Vector3 acceleration = accelerometerReading.Acceleration;

           // Show the numeric values.
           xTextBlock.Text = "X: " + acceleration.X.ToString("0.00");
           yTextBlock.Text = "Y: " + acceleration.Y.ToString("0.00");
           zTextBlock.Text = "Z: " + acceleration.Z.ToString("0.00");

           // Show the values graphically.
           xLinexLine.X2 = xLine.X1 + acceleration.X * 200;
           yLineyLine.Y2 = yLine.Y1 - acceleration.Y * 200;
           zLinezLine.X2 = zLine.X1 - acceleration.Z * 100;
           zLinezLine.Y2 = zLine.Y1 + acceleration.Z * 100;
       }