覆盖xamarin.android中的uri

Question

我正在使用Xamarin.Android中的一些图像，我在下面用来打开文件

 Intent = new Intent();
 Intent.SetType("image/*");
 Intent.PutExtra(Intent.ExtraAllowMultiple,true);
 Intent.SetAction(Intent.ActionGetContent);
 StartActivityForResult(Intent.CreateChooser(Intent, "Select Picture"), code);

我只是使用Bitmap.CompressFormat.Jpeg, 90, fs);压缩文件，其中fs是一个Stream来保存文件。我想覆盖打开的uri（比如用现有的位图替换现有的位图（bmp）。

我想批量做这件事。

我怎样才能做到这一点？

Answer 1

试试这个：

using Android.App;
using Android.Widget;
using Android.OS;
using Android.Content;
using Android.Runtime;
using Java.Lang;
using Android.Net;
using System.Collections.Generic;
using Android.Graphics;
using System.IO;

namespace PictureCopr
{
    [Activity(Label = "PictureCopr", MainLauncher = true)]
    public class MainActivity : Activity
    {
        ImageView miv;
        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);

            // Set our view from the "main" layout resource
            SetContentView(Resource.Layout.Main);
            miv = FindViewById<ImageView>(Resource.Id.iv);
            Intent intent = new Intent();
            intent.SetType("image/*");
            intent.PutExtra(Intent.ExtraAllowMultiple, true);
            intent.SetAction(Intent.ActionGetContent);
            StartActivityForResult(Intent.CreateChooser(intent, "Select Picture"), 1);
        }

        protected override void OnActivityResult(int requestCode, [GeneratedEnum] Result resultCode, Intent data)
        {
            if (resultCode == Result.Ok)
            {
                ClipData clipData = data.ClipData;
                Uri uri = data.Data;
                if (null == uri)//multi
                {
                    List<Uri> list = new List<Uri>(clipData.ItemCount);
                    for (int i = 0; i < clipData.ItemCount; i++)
                    {
                        ClipData.Item itemAt = clipData.GetItemAt(i);
                        list.Add(itemAt.Uri);
                        Android.Util.Log.Error("uri", itemAt.Uri.ToString());

                        try
                        {
                            Bitmap bitmap = BitmapFactory.DecodeStream(ContentResolver.OpenInputStream(itemAt.Uri));

                            var sdCardPath = Android.OS.Environment.ExternalStorageDirectory.AbsolutePath;
                            var filePath = System.IO.Path.Combine(sdCardPath, i+"test.png");

                            var stream = new FileStream(filePath, FileMode.Create);
                            bitmap.Compress(Bitmap.CompressFormat.Png, 90, stream);
                        }
                        catch (Exception e)
                        {
                            Android.Util.Log.Error("Exception", e.Message);
                        }

                    }
                }
                else
                {// single
                    try
                    {
                        Bitmap bitmap = BitmapFactory.DecodeStream(ContentResolver.OpenInputStream(uri));
                        var sdCardPath = Android.OS.Environment.ExternalStorageDirectory.AbsolutePath;
                        var filePath = System.IO.Path.Combine(sdCardPath, "test.png");
                        Android.Util.Log.Error("lv====", filePath);
                        var stream = new FileStream(filePath, FileMode.Create);
                        bitmap.Compress(Bitmap.CompressFormat.Png, 90, stream);
                        stream.Flush();
                        stream.Close();
                    }
                    catch (Exception e)
                    {
                        Android.Util.Log.Error("Exception", e.Message);
                    }
                }

            }
            else
            {
                Android.Util.Log.Error("MainActivtiy", "operation error");
            }
            base.OnActivityResult(requestCode, resultCode, data);

        }
    }
}

更新：

替换它：

var sdCardPath = Android.OS.Environment.ExternalStorageDirectory.AbsolutePath;
var filePath = System.IO.Path.Combine(sdCardPath, i+"test.png");

用这个：

var sdCardPath = Android.OS.Environment.GetExternalStoragePublicDirectory(Environment.DirectoryPictures);
var filePath = System.IO.Path.Combine(sdCardPath.AbsolutePath, i+"test.png");

更新

写入Sd卡演示：

using Android.App;
using Android.Widget;
using Android.OS;
using System.IO;
using Java.IO;

namespace WritToSd
{
    [Activity(Label = "WritToSd", MainLauncher = true)]
    public class MainActivity : Activity
    {
        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);

            // Set our view from the "main" layout resource
            SetContentView(Resource.Layout.Main);
            if (IsSdCardExist())
            {
                Java.IO.File sdCardPath = Environment.GetExternalStoragePublicDirectory(Environment.DirectoryPictures);
                //  destPath: /storage/emulated/0/Pictures/test.png
                string destPath = Path.Combine(sdCardPath.AbsolutePath, "test.png");
                string originPath = Path.Combine(sdCardPath.AbsolutePath, "nULSa.png");
                Android.Util.Log.Error("lv", destPath);
                FileOutputStream fos = new FileOutputStream(destPath , false);
                FileInputStream fis = new FileInputStream(originPath);
                int b;
                byte[] d = new byte[1024 * 1024];
                while ((b = fis.Read(d)) != -1)
                {
                    fos.Write(d, 0, b);
                }
                fos.Flush();
                fos.Close();
                fis.Close();

            }
            else {
                //do something
            }

        }

        public  bool IsSdCardExist()
        {
            return Environment.ExternalStorageState.Equals(
                    Environment.MediaMounted);
        }
    }
}

This is nULSa.png picture.