Xamarin Android: Create Your Own Android Camera App

Step 1- Open Visual Studio->New Project->Templates->Visual C#->Android->Blank app.

Select Blank app. Give project name and project location.



Step 2- Open Solution Explorer-> Project Name->Resources->Layout->Main.axml. Click Open Design View.

Step 3- Go to Tool bar, select button and ImageView. Drag and drop Main.xaml design view.


Step 4- Go to Solution Explorer-> Project Name. Right click to Add->Class, followed by opening new Dialog box. This dialog box is required to select the class and give name for BitmapHelpers.cs.



Step 5- Open Solution Explorer-> Project Name->Resources-> BitmapHelpers.cs. This class is reducing the image size and recycling the memory. It will be used to calculate an image ratio.



C# Code

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Android.App;
using Android.Content;
using Android.OS;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.Graphics;
using Android.Graphics.Drawables;
namespace Camera {
    public static class BitmapHelpers {
        /// This method will recyle the memory help by a bitmap in an ImageView
        public static void RecycleBitmap(this ImageView imageView) {
                if (imageView == null) {
                    return;
                }
                Drawable toRecycle = imageView.Drawable;
                if (toRecycle != null) {
                    ((BitmapDrawable) toRecycle).Bitmap.Recycle();
                }
            }
            /// Load the image from the device, and resize it to the specified dimensions.
        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 {
                InPurgeable = true,
                    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;
        }
    }
}

Step 6- Open Solution Explorer-> Project Name->Resources-> MainActicity.cs. Add NameSpace, given below-

using Android.Provider;
using Java.IO;
using Android.Graphics;
using Android.Content.PM;
using Uri = Android.Net.Uri;
using System.Collections.Generic;

Step 7- First, declare the button, image variables and open Oncreate(). The code is given below-


C# Code

Button BtnTakeImg;
ImageView ImgView;
public static File _file;
public static File _dir;
protected override void OnCreate(Bundle bundle)
{
    base.OnCreate(bundle);
    // Set our view from the "main" layout resource
    SetContentView(Resource.Layout.Main);
    if (IsThereAnAppToTakePictures()) {
        CreateDirectoryForPictures();
        BtnTakeImg = FindViewById < Button > (Resource.Id.btntakepicture);
        ImgView = FindViewById < ImageView > (Resource.Id.ImgTakeimg);
        BtnTakeImg.Click += TakeAPicture;
    }
}

Step 8- We create IsThereAnAppToTakePictures() and CreateDirectoryForPictures().

Step 9- Here, CreateDirectoryForPictures () is to be used to create separate folder for our image. IsThereAnAppToTakePictures() is redirecting to Android Camera path.




C# Code

private void CreateDirectoryForPictures() {
    _dir = new File(Android.OS.Environment.GetExternalStoragePublicDirectory(Android.OS.Environment.DirectoryPictures), "C#Corner");
    if (!_dir.Exists()) {
        _dir.Mkdirs();
    }
}
private bool IsThereAnAppToTakePictures() {
    Intent intent = new Intent(MediaStore.ActionImageCapture);
    IList < ResolveInfo > availableActivities = PackageManager.QueryIntentActivities(intent, PackageInfoFlags.MatchDefaultOnly);
    return availableActivities != null && availableActivities.Count > 0;
}
private void TakeAPicture(object sender, EventArgs eventArgs) {
    Intent intent = new Intent(MediaStore.ActionImageCapture);
    _file = new File(_dir, string.Format("Image_{0}.jpg", Guid.NewGuid()));
    intent.PutExtra(MediaStore.ExtraOutput, Uri.FromFile(_file));
    StartActivityForResult(intent, 102);
}
protected override void OnActivityResult(int requestCode, Result resultCode, Intent data) {
    if (requestCode == 102 && resultCode == Result.Ok) {
        // make it available in the gallery
        Intent mediaScanIntent = new Intent(Intent.ActionMediaScannerScanFile);
        Uri contentUri = Uri.FromFile(_file);
        mediaScanIntent.SetData(contentUri);
        SendBroadcast(mediaScanIntent);
        //Converstion Image Size
        int height = ImgView.Height;
        int width = Resources.DisplayMetrics.WidthPixels;
        using(Bitmap bitmap = _file.Path.LoadAndResizeBitmap(width, height)) {
            //View ImageView
            ImgView.RecycleBitmap();
            ImgView.SetImageBitmap(bitmap);
            //Upload Image in Database
        }
    }
}

Step 10-Finally, give the permission AndroidManifest.XML, stated below- 

<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

Step 11- Press F5 or build and run the Application.

 

Step 12- After running the Application, go and check gallery. See the last captured picture. Finally, we successfully created Xamarin Android, using our own camera app and showing Imageview last captured image.