Xamarin.Android 调用手机拍照功能
最近开发Android遇到了调用本地拍照功能，于是在网上搜了一些方法，加上自己理解的注释，在这儿记录下来省的下次用时候找不到，同事也给正在寻找调用本地拍照功能的小伙伴一些帮助~ 实现思路：首先加载-->判断是否具备拍照功能-->创建图片目录（文件夹）-->点击拍照事件-->返回图片并绑定在控件上显示。 引用命名空间： using System; using System.Collections.Generic; using Android.App; using Android.Content; using Android.Content.PM; using Android.Graphics; using Android.OS; using Android.Provider; using Android.Widget; using Java.IO; using Environment = Android.OS.Environment; using Uri = Android.Net.Uri; 加载： protected override void OnCreate(Bundle bundle) { base.OnCreate(bundle); SetContentView(Resource.Layout.Main); if (IsThereAnAppToTakePictures()) //判断本设备是否存在拍照功能 { CreateDirectoryForPictures(); Button button = FindViewById<Button>(Resource.Id.myButton); _imageView = FindViewById<ImageView>(Resource.Id.imageView1); button.Click += TakeAPicture; } } 判断是否具备拍照功能： /// <summary> /// 判断是否具备拍照功能 /// </summary> /// <returns></returns> private bool IsThereAnAppToTakePictures() { Intent intent = new Intent(MediaStore.ActionImageCapture); IList<ResolveInfo> availableActivities = PackageManager.QueryIntentActivities(intent, PackageInfoFlags.MatchDefaultOnly); return availableActivities != null && availableActivities.Count > 0; } 创建图片目录（文件夹）： /// <summary> /// 创建目录图片 /// </summary> private void CreateDirectoryForPictures() { App._dir = new File( Environment.GetExternalStoragePublicDirectory( Environment.DirectoryPictures), "CameraAppDemo"); //CameraAppDemo if (!App._dir.Exists()) { App._dir.Mkdirs(); } } 点击拍照事件： /// <summary> /// 拍照 /// </summary> /// <param name="sender"></param> /// <param name="eventArgs"></param> private void TakeAPicture(object sender, EventArgs eventArgs) { Intent intent = new Intent(MediaStore.ActionImageCapture); App._file = new File(App._dir, String.Format("myPhoto_{0}.jpg", Guid.NewGuid())); //保存路径 intent.PutExtra(MediaStore.ExtraOutput, Uri.FromFile(App._file)); StartActivityForResult(intent, 0); } 返回图片并绑定在控件上显示： /// <summary> /// 拍照结束执行 /// </summary> /// <param name="requestCode"></param> /// <param name="resultCode"></param> /// <param name="data"></param> protected override void OnActivityResult(int requestCode, Result resultCode, Intent data) { base.OnActivityResult(requestCode, resultCode, data); Intent mediaScanIntent = new Intent(Intent.ActionMediaScannerScanFile); Uri contentUri = Uri.FromFile(App._file); mediaScanIntent.SetData(contentUri); SendBroadcast(mediaScanIntent); // Display in ImageView. We will resize the bitmap to fit the display // Loading the full sized image will consume to much memory // and cause the application to crash. int height = Resources.DisplayMetrics.HeightPixels; int width = _imageView.Height; //获取拍照的位图 App.bitmap = App._file.Path.LoadAndResizeBitmap(width, height); if (App.bitmap != null) { //将图片绑定到控件上 _imageView.SetImageBitmap(App.bitmap); //清空bitmap 否则会出现oom问题 App.bitmap = null; } // Dispose of the Java side bitmap. GC.Collect(); } LoadAndResizeBitmap方法： public static Bitmap LoadAndResizeBitmap(this string fileName, int width, int height) { // First we get the the dimensions of the file on disk BitmapFactory.Options options = new BitmapFactory.Options { InJustDecodeBounds = true }; BitmapFactory.DecodeFile(fileName, options); // Next we calculate the ratio that we need to resize the image by // in order to fit the requested dimensions. int outHeight = options.OutHeight; int outWidth = options.OutWidth; int inSampleSize = 1; if (outHeight > height || outWidth > width) { inSampleSize = outWidth > outHeight ? outHeight / height : outWidth / width; } // Now we will load the image and have BitmapFactory resize it for us. options.InSampleSize = inSampleSize; options.InJustDecodeBounds = false; Bitmap resizedBitmap = BitmapFactory.DecodeFile(fileName, options); return resizedBitmap; } App类： public static class App { public static File _file; public static File _dir; public static Bitmap bitmap; } 最后再附上下载地址： 链接: https://pan.baidu.com/s/1h0Zg1jkCyKrZKN6N5eIB8Q 密码: wgdm
