【Android】20.3 拍照和视频录制

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <Button
        android:id="@+id/ch2003_btn1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="拍照" />
  <Button
      android:id="@+id/ch2003_btn2"
      android:layout_width="fill_parent"
      android:layout_height="wrap_content"
      android:text="视频录制" />
  <TextView
        android:text=""
        android:textAppearance="?android:attr/textAppearanceSmall"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/ch2003_textView1" />
  <ImageView
        android:src="@android:drawable/ic_menu_gallery"
        android:layout_width="fill_parent"
        android:layout_height="300dp"
        android:id="@+id/ch2003_imageView1"
        android:adjustViewBounds="true" />
  <VideoView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/ch2003_videoView1" />
</LinearLayout>

using Android.Widget;
using Android.Graphics.Drawables;
using Android.Graphics;

namespace MyDemos.SrcDemos
{
    public static class ch2003BitmapHelpers
    {
        public static void RecycleBitmap(ImageView imageView)
        {
            if (imageView == null)
            {
                return;
            }

            Drawable toRecycle = imageView.Drawable;
            if (toRecycle != null)
            {
                ((BitmapDrawable)toRecycle).Bitmap.Recycle();
            }
        }

        public static Bitmap LoadAndResizeBitmap(string fileName, int width, int height)
        {
            BitmapFactory.Options options = new BitmapFactory.Options
            {
                InPurgeable = true,
                InJustDecodeBounds = true
            };
            BitmapFactory.DecodeFile(fileName, options);
            int outHeight = options.OutHeight;
            int outWidth = options.OutWidth;
            int inSampleSize = 1;
            if (outHeight > height || outWidth > width)
            {
                if(outWidth > outHeight)
                {
                    inSampleSize = outHeight / height;
                }
                else
                {
                    inSampleSize = outWidth / width;
                }
            }
            options.InSampleSize = inSampleSize;
            options.InJustDecodeBounds = false;
            Bitmap resizedBitmap = BitmapFactory.DecodeFile(fileName, options);
            return resizedBitmap;
        }
    }
}

using System.Collections.Generic;
using Android.App;
using Android.Content;
using Android.OS;
using Android.Runtime;
using Android.Widget;
using Android.Provider;
using Android.Content.PM;
using Android.Graphics;

using Android.Net;
using Java.IO;

namespace MyDemos.SrcDemos
{
    [Activity(Label = "ch2003MainActivity")]
    [IntentFilter(new[] { Intent.ActionMain },
        Categories = new[] { Intent.CategoryDefault, ch.MyDemosCategory })]
    public class ch2003MainActivity : Activity
    {
        private File file;
        string dirPath;
        string filePath;
        private ImageView imageView1;
        private VideoView videoView1;
        private TextView textView1;
        private MediaType mediaType;

        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);

            SetContentView(Resource.Layout.ch2003Main);
            textView1 = FindViewById<TextView>(Resource.Id.ch2003_textView1);
            imageView1 = FindViewById<ImageView>(Resource.Id.ch2003_imageView1);
            videoView1 = FindViewById<VideoView>(Resource.Id.ch2003_videoView1);
            Button btn1 = FindViewById<Button>(Resource.Id.ch2003_btn1);
            Button btn2 = FindViewById<Button>(Resource.Id.ch2003_btn2);

            //判断相机是否可用（是否有一个App正在准备拍照）
            if (IsThereAnAppToTakePictures())
            {
                dirPath = $"{Environment.ExternalStorageDirectory.Path}/{Environment.DirectoryPictures}/MyDemosPictures";
                if (!System.IO.Directory.Exists(dirPath))
                {
                    System.IO.Directory.CreateDirectory(dirPath);
                }
                btn1.Click += delegate
                {
                    //拍照
                    mediaType = MediaType.Image;
                    Intent imageIntent = new Intent(MediaStore.ActionImageCapture);
                    filePath = dirPath + $"/PP{System.DateTime.Now:yyyyMMdd_hhmmss}.jpg";
                    file = new File(filePath);
                    imageIntent.PutExtra(MediaStore.ExtraOutput, Uri.FromFile(file));
                    StartActivityForResult(imageIntent, 100);
                };
                btn2.Click += delegate
                {
                    //视频录制
                    mediaType = MediaType.Video;
                    Intent videoIntent = new Intent(MediaStore.ActionVideoCapture);
                    filePath = dirPath + $"/PP{System.DateTime.Now:yyyyMMdd_hhmmss}.mp4";
                    file = new File(filePath);
                    videoIntent.PutExtra(MediaStore.ExtraOutput, Uri.FromFile(file));
                    videoIntent.PutExtra(MediaStore.ExtraVideoQuality, 1);
                    StartActivityForResult(videoIntent, 200);
                };
            }
            else
            {
                //如果相机不可用，禁用按钮
                btn1.Text = "相机不可用，无法拍照";
                btn2.Text = "相机不可用，无法录制视频";
                btn1.Enabled = btn2.Enabled = false;
            }
        }

        /// <summary>
        /// 判断相机是否可用（是否有一个App正在准备拍照）
        /// </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;
        }

        protected override void OnActivityResult(int requestCode, [GeneratedEnum] Result resultCode, Intent data)
        {
            base.OnActivityResult(requestCode, resultCode, data);

            // 使其可以在图库中可用，即浏览图库时能看到相机拍摄的照片
            Intent mediaScanIntent = new Intent(Intent.ActionMediaScannerScanFile);
            Uri contentUri = Uri.FromFile(file);
            mediaScanIntent.SetData(contentUri);
            SendBroadcast(mediaScanIntent);

            if(mediaType== MediaType.Image)
            {
                imageView1.Visibility = Android.Views.ViewStates.Visible;
                videoView1.Visibility = Android.Views.ViewStates.Gone;
                //辅助程序（ch2003BitmapHelpers.cs）会自动缩放该图片以适应屏幕大小。
                int width = Resources.DisplayMetrics.WidthPixels;
                int height = imageView1.Height;
                using (Bitmap bitmap = ch2003BitmapHelpers.LoadAndResizeBitmap(filePath, width, height))
                {
                    ch2003BitmapHelpers.RecycleBitmap(imageView1);
                    imageView1.SetImageBitmap(bitmap);
                    imageView1.RefreshDrawableState();
                }
                textView1.Text = "拍照结果：\n" + filePath;
            }
            else
            {
                imageView1.Visibility = Android.Views.ViewStates.Gone;
                videoView1.Visibility = Android.Views.ViewStates.Visible;
                videoView1.SetVideoURI(Uri.Parse(filePath));
                videoView1.SetMediaController(new MediaController(this));
                videoView1.Start();
                textView1.Text = "视频录制结果：\n" + filePath;
            }
        }
    }
}