如何使用我制作的应用程序将图像保存到图库？

Question

我有这个Xamarin Android 应用程序（不是 Forms），它可以打开相机并让我拍照并随拍或拍一张新照片。之后，ImageView使用位图向我展示应用程序上的图片。我无法使用位图保存到画廊（我不知道该怎么做，或者是否有更简单的方法）。我需要应用程序获取应用程序拍摄的最后一张照片（为什么需要保存它）并通过单击按钮将其发送到服务器（我也需要一些帮助）。这就是我需要做的。这是代码MainActivity.cs：using Android.App;using Android.Widget;using Android.OS;using Android.Content;using Android.Provider;using Android.Runtime;using Android.Graphics;namespace CameraApp{    [Activity(Label = "@string/app_name", Theme = "@style/AppTheme", MainLauncher = true)]    public class MainActivity : Activity    {        ImageView imageView;        protected override void OnCreate(Bundle bundle)        {            base.OnCreate(bundle);            SetContentView(Resource.Layout.activity_main);            Button btnCamera = FindViewById<Button>(Resource.Id.btnCamera);            imageView = FindViewById<ImageView>(Resource.Id.imageView);            btnCamera.Click += BtnCamera_Click;        }        protected override void OnActivityResult(int requestCode, [GeneratedEnum] Result resultCode, Intent data)        {            base.OnActivityResult(requestCode, resultCode, data);            Bitmap bitmap = (Bitmap)data.Extras.Get("data");            imageView.SetImageBitmap(bitmap);        }        private void BtnCamera_Click(object sender, System.EventArgs e)        {            Intent intent = new Intent(MediaStore.ActionImageCapture);            StartActivityForResult(intent, 0);        }    }}

Answer 1

我写了一个关于你的需求的演示。我添加了相机和外部存储权限并将图像存储到画廊，这里正在运行 GIF。

https://i.stack.imgur.com/FPLUY.gif

有运行demo的代码。我添加了运行时权限（相机和WriteExternalStorage）请求。并判断用户没有拍照的情况，然后返回应用程序。

[Activity(Label = "@string/app_name", Theme = "@style/AppTheme", MainLauncher = true)]

public class MainActivity : AppCompatActivity, ActivityCompat.IOnRequestPermissionsResultCallback

{

    Button button1;

    ImageView imageView1;

    View layout;

    static readonly int REQUEST_CAMERA_WriteExternalStorage = 0;

    protected override void OnCreate(Bundle savedInstanceState)

    {

        base.OnCreate(savedInstanceState);

        // Set our view from the "main" layout resource

        SetContentView(Resource.Layout.activity_main);

        layout = FindViewById<RelativeLayout>(Resource.Id.sample_main_layout);

        button1 = FindViewById<Button>(Resource.Id.button1);

        imageView1 = FindViewById<ImageView>(Resource.Id.imageView1);

        button1.Click += (o, e) =>

        {

            CheckPermission();

        };

    }

    public  void CheckPermission()

    {

        if ((ContextCompat.CheckSelfPermission(this, Manifest.Permission.Camera) == (int)Permission.Granted)&& (ContextCompat.CheckSelfPermission(this, Manifest.Permission.WriteExternalStorage) == (int)Permission.Granted))

        {

            // Camera and store permission has  been granted

            ShowCamera();

        }

        else

        {

            // Camera and store permission has not been granted

            RequestPermission();

        }

    }

    private void RequestPermission()

    {

        ActivityCompat.RequestPermissions(this, new String[] { Manifest.Permission.Camera, Manifest.Permission.WriteExternalStorage }, REQUEST_CAMERA_WriteExternalStorage);

    }

    //get result of persmissions

    public override void OnRequestPermissionsResult(int requestCode, string[] permissions, [GeneratedEnum] Permission[] grantResults)

    {

        if (requestCode == REQUEST_CAMERA_WriteExternalStorage)

        {

            if ( PermissionUtil.VerifyPermissions(grantResults))

            {

                // All required permissions have been granted, display Camera.

                ShowCamera();

            }

            else

            {

                // permissions did not grant, push up a snackbar to notificate USERS

                Snackbar.Make(layout, Resource.String.permissions_not_granted, Snackbar.LengthShort).Show();

            }

        }

        else

        {

            base.OnRequestPermissionsResult(requestCode, permissions, grantResults);

        }

    }

    private void ShowCamera()

    {

        Intent intent = new Intent(MediaStore.ActionImageCapture);

        StartActivityForResult(intent, 0);

    }

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

    {

        base.OnActivityResult(requestCode, resultCode, data);

        Bitmap bitmap=null;

        //If user did not take a photeo , he will get result of bitmap, it is null

        try {

             bitmap = (Bitmap)data.Extras.Get("data");

        } catch(Exception e)

        {

            Log.Error("TakePhotoDemo1", e.Message);

            Toast.MakeText(this, "You did not take a photo", ToastLength.Short).Show();

        }

        if (bitmap != null)

        {

            MediaStore.Images.Media.InsertImage(ContentResolver, bitmap, "screen", "shot");

            imageView1.SetImageBitmap(bitmap);

        }

        else

        {

            Toast.MakeText(this, "You did not take a photo", ToastLength.Short).Show();

        }

    }

}

PermissionUtil.cs通过验证给定数组中的每个条目是否具有值 Permission.Granted，检查是否已授予所有给定权限。

   public abstract class PermissionUtil

{

    public static bool VerifyPermissions(Permission[] grantResults)

    {

        // At least one result must be checked.

        if (grantResults.Length < 1)

            return false;

        // Verify that each required permission has been granted, otherwise return false.

        foreach (Permission result in grantResults)

        {

            if (result != Permission.Granted)

            {

                return false;

            }

        }

        return true;

    }

}

有我的代码。

https://github.com/851265601/TakePhotoDemo1

MediaStore.Images.Media.InsertImage前面的代码将在 gallery( )的末尾添加图像。如果您想修改日期以使其出现在开头或任何其他元数据中，请参阅此链接。 https://gist.github.com/samkirton/0242ba81d7ca00b475b9

Answer 2

您可以通过 MediaStore 插入图像

MediaStore.Images.Media.InsertImage(this, yourBitmap, yourTitle, yourDescription);

注意：您可能想为此添加写入外部存储权限。