从存储中导入文件时出现 FileNotFoundException (Android Studio)

Question

在过去的几天里，我一直在试图找出我做错了什么。每当用户上传文件（非图像）时，我尝试将 URI 对象转换为文件，然后转换为字节数组，我会收到此错误：

java.io.FileNotFoundException: /document/2301（没有这样的文件或目录）

我显然上传了一些东西，因为它向我展示了某种路径。这是我的代码：

主要活动-

import android.Manifest;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.media.MediaFormat;
import android.net.Uri;
import android.provider.MediaStore;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.ImageView;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        if (checkSelfPermission(Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {

            requestPermissions(new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, 1);

        } else {

            getFile();

        }
    }

    public void getFile() {

        Intent intent = new Intent();
        intent.setType("application/pdf");
        intent.setAction(Intent.ACTION_GET_CONTENT);

        startActivityForResult(intent, 1);

    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);

        if (requestCode == 1) {

            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                getFile();

            }


        }

    }


    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode == 1 && resultCode == RESULT_OK && data != null) {

            Uri selectedFile = data.getData();

            Log.i("Path", selectedFile.getPath());

            File file = new File(selectedFile.getPath());

            byte[] b = new byte[(int) file.length()];
            try {
                FileInputStream fileInputStream = new FileInputStream(file);
                fileInputStream.read(b);
                for (int i = 0; i < b.length; i++) {
                    System.out.print((char)b[i]);
                }
            } catch (FileNotFoundException e) {
                System.out.println("File Not Found.");
                e.printStackTrace();
            }
            catch (IOException e1) {
                System.out.println("Error Reading The File.");
                e1.printStackTrace();
            }

        }

    }
}

感谢任何形式的帮助！

Answer 1

文件在内部存储中不存在。使用以下代码解决问题。

 public static String getPath(Context context, Uri uri) {
    final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;

    // DocumentProvider
    if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {
        // ExternalStorageProvider
        if (isExternalStorageDocument(uri)) {
            final String docId = DocumentsContract.getDocumentId(uri);
            final String[] split = docId.split(":");
            final String type = split[0];

            if ("primary".equalsIgnoreCase(type)) {
                return Environment.getExternalStorageDirectory() + "/" + split[1];
            }
            // TODO handle non-primary volumes
        }
        // DownloadsProvider
        else if (isDownloadsDocument(uri)) {
            final String id = DocumentsContract.getDocumentId(uri);
            final Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), Long.valueOf(id));
            return getDataColumn(context, contentUri, null, null);
        }
        // MediaProvider
        else
        if (isMediaDocument(uri)) {
            final String docId = DocumentsContract.getDocumentId(uri);
            final String[] split = docId.split(":");
            final String type = split[0];
            Uri contentUri = null;
            if ("image".equals(type)) {
                contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
            } else if ("video".equals(type)) {
                contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
            } else if ("audio".equals(type)) {
                contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
            }
            final String selection = "_id=?";
            final String[] selectionArgs = new String[] {split[1]};
            return getDataColumn(context, contentUri, selection, selectionArgs);
        }
    }
    // MediaStore (and general)
    else if ("content".equalsIgnoreCase(uri.getScheme())) {
        // Return the remote address
        if (isGooglePhotosUri(uri))
            return uri.getLastPathSegment();
        return getDataColumn(context, uri, null, null);
    }
    // File
    else if ("file".equalsIgnoreCase(uri.getScheme())) {
        return uri.getPath();
    }
    return null;
}

public static String getDataColumn(Context context, Uri uri, String selection, String[] selectionArgs) {
    Cursor cursor = null;
    final String column = "_data";
    final String[] projection = { column };
    try {
        cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs, null);
        if (cursor != null && cursor.moveToFirst()) {
            final int index = cursor.getColumnIndexOrThrow(column);
            return cursor.getString(index);
        }
    } finally {
        if (cursor != null)
            cursor.close();
    }
    return null;
}

public static boolean isExternalStorageDocument(Uri uri) {
    return "com.android.externalstorage.documents".equals(uri.getAuthority());
}

/**
 * @param uri The Uri to check.
 * @return Whether the Uri authority is DownloadsProvider.
 */
public static boolean isDownloadsDocument(Uri uri) {
    return "com.android.providers.downloads.documents".equals(uri.getAuthority());
}

/**
 * @param uri The Uri to check.
 * @return Whether the Uri authority is MediaProvider.
 */
public static boolean isMediaDocument(Uri uri) {
    return "com.android.providers.media.documents".equals(uri.getAuthority());
}

/**
 * @param uri The Uri to check.
 * @return Whether the Uri authority is Google Photos.
 */
public static boolean isGooglePhotosUri(Uri uri) {
    return "com.google.android.apps.photos.content".equals(uri.getAuthority());
}

使用以下代码浏览任何格式的文件。

    public void browseClick() {

    Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
    intent.setType("*/*");
    intent.addCategory(Intent.CATEGORY_OPENABLE);
    //intent.putExtra("browseCoa", itemToBrowse);
    //Intent chooser = Intent.createChooser(intent, "Select a File to Upload");
    try {
        //startActivityForResult(chooser, FILE_SELECT_CODE);
        startActivityForResult(Intent.createChooser(intent, "Select a File to Upload"),FILE_SELECT_CODE);
    } catch (Exception ex) {
        System.out.println("browseClick :"+ex);//android.content.ActivityNotFoundException ex
    }
}

然后在 onActivityResult 中获取该文件路径，如下所示。

    @Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == FILE_SELECT_CODE) {
        if (resultCode == RESULT_OK) {
            try {
              Uri uri = data.getData();

                if (filesize >= FILE_SIZE_LIMIT) {
                    Toast.makeText(this,"The selected file is too large. Selet a new file with size less than 2mb",Toast.LENGTH_LONG).show();
                } else {
                    String mimeType = getContentResolver().getType(uri);
                    if (mimeType == null) {
                        String path = getPath(this, uri);
                        if (path == null) {
                            filename = FilenameUtils.getName(uri.toString());
                        } else {
                            File file = new File(path);
                            filename = file.getName();
                        }
                    } else {
                        Uri returnUri = data.getData();
                        Cursor returnCursor = getContentResolver().query(returnUri, null, null, null, null);
                        int nameIndex = returnCursor.getColumnIndex(OpenableColumns.DISPLAY_NAME);
                        int sizeIndex = returnCursor.getColumnIndex(OpenableColumns.SIZE);
                        returnCursor.moveToFirst();
                        filename = returnCursor.getString(nameIndex);
                        String size = Long.toString(returnCursor.getLong(sizeIndex));
                    }
   File fileSave = getExternalFilesDir(null);
    String sourcePath = getExternalFilesDir(null).toString();
    try {
                        copyFileStream(new File(sourcePath + "/" + filename), uri,this);

                    } catch (Exception e) {
                        e.printStackTrace();
                    }
  }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
}
private void copyFileStream(File dest, Uri uri, Context context)
        throws IOException {
    InputStream is = null;
    OutputStream os = null;
    try {
        is = context.getContentResolver().openInputStream(uri);
        os = new FileOutputStream(dest);
        byte[] buffer = new byte[1024];
        int length;

        while ((length = is.read(buffer)) > 0) {
            os.write(buffer, 0, length);

        }
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        is.close();
        os.close();
    }
}

在此之后，您可以通过适当的操作从您保存文件的应用程序外部存储中打开此文件。

礼貌：https://stackoverflow.com/a/36129285/6050536

Answer 2

private String fileToBase64Conversion(Uri file) {
        InputStream inputStream = null;//You can get an inputStream using any IO API
        ByteArrayOutputStream output = new ByteArrayOutputStream();
        try {
            inputStream = context.getContentResolver().openInputStream(file);
            byte[] buffer = new byte[8192];
            int bytesRead;
            Base64OutputStream outputBase64 = new Base64OutputStream(output, Base64.DEFAULT);
            try {
                while ((bytesRead = inputStream.read(buffer)) != -1) {
                    outputBase64.write(buffer, 0, bytesRead);
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
            outputBase64.close();
        } catch (Exception ex) {

        }

        return outputBase64.toString();
    }