Windows phone 8 学习笔记(7) 设备-白红宇

Windows phone 8 学习笔记(7) 设备

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发布时间：2019-06-09

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原文:

本节主要涉及到 Windows phone 8 手机支持的各类设备，包括相机、设备状态，振动装置等。还有各类感应器，包括磁力计、加速度器和陀螺仪。通过设备状态可以获取内存、硬件、电源、键盘等状态；通过相机捕获照片和视频；各类感应器帮助我们获取设备的运动状态等。

快速导航：

一、设备状态

通过DeviceStatus 类我们可以确定设备的相关状态信息，比如内存大小啊，固件版本啊，还有是否部署了物理键盘等信息，以及与电源的相关信息，当前是电池还是外部电源等。

我们通过下面的代码展示如何获取这些信息。

[C#]

protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)        {           var timer = new DispatcherTimer();            timer.Interval = new TimeSpan(0, 0, 10);            timer.Tick += new EventHandler((a, b) =>            {                //当前内存使用了多少字节                var x = Microsoft.Phone.Info.DeviceStatus.ApplicationCurrentMemoryUsage;                textblock1.Text = "当前内存：" + convert(x);                //高峰时内存使用了多少字节                var y = Microsoft.Phone.Info.DeviceStatus.ApplicationPeakMemoryUsage;                textblock2.Text = "峰值内存：" + convert(y);            });            timer.Start();            textblock3.Text = "设备制造商名："+ DeviceStatus.DeviceManufacturer;            textblock4.Text = "设备名：" + DeviceStatus.DeviceName;            textblock5.Text = "固件版本："+ DeviceStatus.DeviceFirmwareVersion;            textblock6.Text = "硬件版本："+ DeviceStatus.DeviceHardwareVersion;            textblock7.Text = "物理内存大小："+convert( DeviceStatus.DeviceTotalMemory);            textblock8.Text = "应用进程可分配最大额外内存：" + convert(DeviceStatus.ApplicationMemoryUsageLimit);            textblock9.Text ="是否包含硬件键盘："+ DeviceStatus.IsKeyboardPresent.ToString();            textblock10.Text = "是否部署硬件键盘：" + DeviceStatus.IsKeyboardDeployed.ToString();            textblock11.Text = "电源状态：" + DeviceStatus.PowerSource.ToString();            //关闭或部署键盘时            DeviceStatus.KeyboardDeployedChanged += new EventHandler((a, b) => {                textblock9.Text = "键盘变更，是否包含硬件键盘：" + DeviceStatus.IsKeyboardPresent.ToString();            });            //设备电源变更时            DeviceStatus.PowerSourceChanged += new EventHandler((a, b) =>            {                textblock11.Text = "电源状态变更：" + DeviceStatus.PowerSource.ToString();            });            base.OnNavigatedTo(e);        }        private string convert(long x)        {            return Math.Round(x / (1024.0 * 1024.0), 2) + "M";        }

二、相机

有两个类可以调用相机，分别是PhotoCamera和PhotoCaptureDevice，一般如果要支持WP7以及对相机基本调用则使用前者，后者用于相机的高级捕获。

1.PhotoCamera

我们首先通过PhotoCamera来访问相机，我们可以实现一个具备拍照功能的基本相机，包含自动对焦、闪光灯、分辨率调整等功能，下面代码演示了如何使用。

[XAML]

[C#]

public partial class MainPage : PhoneApplicationPage    {        // 构造函数        public MainPage()        {            InitializeComponent();        }        PhotoCamera photoCamera;        MediaLibrary library = new MediaLibrary();        protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)        {            //判断是否支持相机            if (PhotoCamera.IsCameraTypeSupported(CameraType.Primary))            {                textblock1.Text = "当前取景：后置摄像头";                photoCamera = new PhotoCamera(CameraType.Primary);            }            else if (PhotoCamera.IsCameraTypeSupported(CameraType.FrontFacing))            {                textblock1.Text = "当前取景：前置摄像头";                photoCamera = new PhotoCamera(CameraType.FrontFacing);            }            else            {                textblock1.Text = "设备不支持相机";                return;            }            textblock2.Text = "相机正在初始化中.";            viewfinderBrush.SetSource(photoCamera);            //相机初始化完成时            photoCamera.Initialized += (a, b) =>            {                if (b.Succeeded)                {                    this.Dispatcher.BeginInvoke(() =>                    {                        SupportedFlashModesInit();                        AvailableResolutionsInit();                        textblock2.Text = "相机初始化完成.";                    });                }            };            //有图像可用时（拍摄完成）            photoCamera.CaptureImageAvailable += (a, b) =>            {                this.Dispatcher.BeginInvoke(() => { textblock2.Text = "正在保存照片."; });                library.SavePictureToCameraRoll(Guid.NewGuid().ToString() + ".jpg", b.ImageStream);                this.Dispatcher.BeginInvoke(() => { textblock2.Text = "照片保存成功."; });            };            //对焦完成时            photoCamera.AutoFocusCompleted += (a, b) =>            {                this.Dispatcher.BeginInvoke(() =>                {                    textblock2.Text = "自动对焦完成.";                    focusBrackets.Visibility = Visibility.Collapsed;                });            };            base.OnNavigatedTo(e);        }        ///         /// 显示支持的闪光模式        /// 
        private void SupportedFlashModesInit()        {            List
         
           flashModes = new List
          
           () { "关" };            if (photoCamera.IsFlashModeSupported(FlashMode.On)) flashModes.Add("开");            if (photoCamera.IsFlashModeSupported(FlashMode.Auto)) flashModes.Add("自动");            if (photoCamera.IsFlashModeSupported(FlashMode.RedEyeReduction)) flashModes.Add("红眼");            listbox1.ItemsSource = flashModes;        }        /// 
                   /// 显示支持的分辨率        /// 
        private void AvailableResolutionsInit()        {            listbox2.ItemsSource = photoCamera.AvailableResolutions;        }        //对焦        private void Button_Click_1(object sender, RoutedEventArgs e)        {            //是否支持自动对焦            if (photoCamera.IsFocusSupported == true)            {                try                {                    photoCamera.Focus();                }                catch(Exception ex)                {                    this.Dispatcher.BeginInvoke(() => { textblock2.Text = "对焦错误：" + ex.Message; });                }            }            else            {                this.Dispatcher.BeginInvoke(() => { textblock2.Text = "相机不支持自动对焦."; });            }        }        //拍照        private void Button_Click_2(object sender, RoutedEventArgs e)        {            if (photoCamera != null)            {                try                {                    photoCamera.CaptureImage();                }                catch (Exception ex)                {                    this.Dispatcher.BeginInvoke(() => { textblock2.Text = "拍照错误：" + ex.Message; });                }            }        }        //特定点对焦        private void canvas1_Tap(object sender, GestureEventArgs e)        {            if (photoCamera == null) return;            if (!photoCamera.IsFocusAtPointSupported)            {                textblock2.Text = "不支持特定点对焦";                return;            }            try            {                Point tapLocation = e.GetPosition(canvas1);                focusBrackets.SetValue(Canvas.LeftProperty, tapLocation.X - 30);                focusBrackets.SetValue(Canvas.TopProperty, tapLocation.Y - 28);                double focusXPercentage = tapLocation.X / canvas1.Width;                double focusYPercentage = tapLocation.Y / canvas1.Height;                focusBrackets.Visibility = Visibility.Visible;                photoCamera.FocusAtPoint(focusXPercentage, focusYPercentage);                this.Dispatcher.BeginInvoke(delegate()                {                    textblock2.Text = String.Format("针对位置 [{0:N2} , {1:N2}] 开始对焦", focusXPercentage, focusYPercentage);                });            }            catch (Exception focusError)            {                this.Dispatcher.BeginInvoke(delegate()                {                    textblock2.Text ="对焦错误："+ focusError.Message;                    focusBrackets.Visibility = Visibility.Collapsed;                });            }        }        //切换闪光灯模式        private void listbox1_SelectionChanged(object sender, SelectionChangedEventArgs e)        {            if (e.AddedItems.Count == 0) return;            switch (e.AddedItems[0].ToString())            {                case "关":                    photoCamera.FlashMode = FlashMode.Off;                    break;                case "自动":                    photoCamera.FlashMode = FlashMode.Auto;                    break;                case "红眼":                    photoCamera.FlashMode = FlashMode.RedEyeReduction;                    break;                case "开":                    photoCamera.FlashMode = FlashMode.On;                    break;            }            textblock2.Text = "已将闪光模式设置为：" + e.AddedItems[0].ToString();        }        //切换分辨率        private void listbox2_SelectionChanged(object sender, SelectionChangedEventArgs e)        {            if (e.AddedItems.Count == 0) return;            photoCamera.Resolution = (Size)e.AddedItems[0];            textblock2.Text = "已将分辨率设置为：" + photoCamera.Resolution.ToString();        }    }

2.PhotoCaptureDevice

PhotoCaptureDevice对相机的高级捕获很多都是用于支持后续版本的，下面我们简单演示下通过PhotoCaptureDevice捕获照片并显示出来的方法。

[XAML]

[C#]

public partial class MainPage : PhoneApplicationPage    {        // 构造函数        public MainPage()        {            InitializeComponent();        }        PhotoCaptureDevice photoCaptureDevice;        CameraCaptureSequence cameraCaptureSequence;        MemoryStream captureStream = new MemoryStream();        protected async override void OnNavigatedTo(NavigationEventArgs e)        {            if (PhotoCaptureDevice.AvailableSensorLocations.Contains(CameraSensorLocation.Back))            {                var SupportedResolutions = PhotoCaptureDevice.GetAvailableCaptureResolutions(CameraSensorLocation.Back);                photoCaptureDevice = await PhotoCaptureDevice.OpenAsync(CameraSensorLocation.Back, SupportedResolutions[0]);            }            else if (PhotoCaptureDevice.AvailableSensorLocations.Contains(CameraSensorLocation.Front))            {                var SupportedResolutions = PhotoCaptureDevice.GetAvailableCaptureResolutions(CameraSensorLocation.Front);                photoCaptureDevice = await PhotoCaptureDevice.OpenAsync(CameraSensorLocation.Front, SupportedResolutions[0]);            }            else            {                return;            }            viewfinderBrush.SetSource(photoCaptureDevice);                        cameraCaptureSequence = photoCaptureDevice.CreateCaptureSequence(1);            // Set camera properties.            photoCaptureDevice.SetProperty(KnownCameraPhotoProperties.FlashMode, FlashState.On);            photoCaptureDevice.SetProperty(KnownCameraGeneralProperties.PlayShutterSoundOnCapture, true);            photoCaptureDevice.SetProperty(KnownCameraGeneralProperties.AutoFocusRange, AutoFocusRange.Infinity);            cameraCaptureSequence.Frames[0].DesiredProperties[KnownCameraPhotoProperties.SceneMode] = CameraSceneMode.Portrait;            cameraCaptureSequence.Frames[0].CaptureStream = captureStream.AsOutputStream();            await photoCaptureDevice.PrepareCaptureSequenceAsync(cameraCaptureSequence);            base.OnNavigatedTo(e);        }        public async void Capture()        {            await cameraCaptureSequence.StartCaptureAsync();            var b = new BitmapImage();            b.SetSource(captureStream);            img1.Source = b;        }        private void Button_Click_1(object sender, RoutedEventArgs e)        {            Capture();        }    }

三、罗盘传感器

罗盘传感器用于感知地球磁场，功能主要是用于确定方向，有了它，我们可以开发类似指南针的应用。

不是每个设备都必须支持罗盘传感器的，所以我们需要在使用前判断设备是否支持。

[C#]

if (!Compass.IsSupported) {     MessageBox.Show("设备不支持罗盘");     return; }

如果设备支持，我们还需要判断罗盘的精度，如果精度不高，需要提醒用户校对精度。当罗盘获取数据时，通过CurrentValueChanged事件处理获取的数据。

[XAML]

[C#]

compass = new Compass();//指定数据更新时间间隔.compass.TimeBetweenUpdates = TimeSpan.FromMilliseconds(20);//从罗盘传感器获取数据时发生compass.CurrentValueChanged += new EventHandler
         
          
           >(compass_CurrentValueChanged);//罗盘需要校验时发生compass.Calibrate += new EventHandler
           
            (compass_Calibrate); compass.Start();//从传感器获取新数据时发生void compass_CurrentValueChanged(object sender, SensorReadingEventArgs
            
              e){    //获取到地球地理北极顺时值偏移角度    trueHeading = e.SensorReading.TrueHeading;}//罗盘需要校验时发生void compass_Calibrate(object sender, CalibrationEventArgs e){    Dispatcher.BeginInvoke(() =>    {        //罗盘需要校验，canvas1指示用户校验        canvas1.Visibility = Visibility.Visible;    });}

四、加速度计

加速度计用于测试某个时刻设备在空间中的姿态。它与重力相关。它的取值在分为x、y、z三个方向取值，下面我们理解下这些取值含义。我们假设设备正面向上平躺在水平桌面为参照标准：

x：设备左倾的趋势越大，值越小，左倾90度时，值为-1；相反，右倾时值越大，最大为1。

y：设备后倾的趋势越大，值越小，后倾90度时，值为-1；相反，前倾时值越大，最大为1。

z：设备下倾的趋势越大，值越大，下倾180度（翻面了）时，值为1；正面朝上（不动）时，最为-1。

总的说来，x控制左右，y控制前后，z控制上下。下面我们在看看如何使用。

[C#]

//校验设备是否支持if (!Accelerometer.IsSupported){    MessageBox.Show("设备不支持重力感应");}var accelerometer = new Accelerometer();accelerometer.TimeBetweenUpdates = TimeSpan.FromMilliseconds(20);//从加速度传感器获取数据时发生accelerometer.CurrentValueChanged += new EventHandler
         
          
           >(accelerometer_CurrentValueChanged);accelerometer.Start();//从加速度传感器获取数据时发生void accelerometer_CurrentValueChanged(object sender, SensorReadingEventArgs
           
             e){    //获取到设备加速度矢量    vector3 = e.SensorReading.Acceleration;}

五、陀螺仪

陀螺仪用于检测设备在空间中的旋转趋势。它的三个取值即为设备绕三个坐标轴的旋转速度。

x：水平左右向轴的旋转速度。

y：水平前后向轴的旋转速度。

z：垂直上下向轴的旋转速度。

然后我们看看如何调用陀螺仪。

[C#]

//判断设备是否支持陀螺仪if (!Gyroscope.IsSupported){    MessageBox.Show("设备不支持陀螺仪");}gyroscope = new Gyroscope();gyroscope.TimeBetweenUpdates = TimeSpan.FromMilliseconds(20);//从陀螺仪获取数据时发生gyroscope.CurrentValueChanged += new EventHandler
         
          
           >(gyroscope_CurrentValueChanged);//启动陀螺仪，实际使用可能启动失败需要捕获异常gyroscope.Start();//从陀螺仪获取数据是发生void gyroscope_CurrentValueChanged(object sender, SensorReadingEventArgs
           
             e){    //获取设备绕每个轴的旋转速度    var rotationRate = e.SensorReading.RotationRate;}

六、如何振动手机

手机的振动可以通过一句简单的API完成，在某些情况下可能还需要设置振动的世界，以及提前结束振动。下面代码演示了如何操作。

[C#]

VibrateController testVibrateController = VibrateController.Default;            //定义振动时间            testVibrateController.Start(TimeSpan.FromSeconds(3));            //在振动时间达到前停止振动            testVibrateController.Stop();

作者：[ ]

出处：[ ]