使用内容解析器获取输入流

InputStream inputStream = getContentResolver().openInputStream(uri);

然后将输入流复制到文件中

FileUtils.copyInputStreamToFile(inputStream, file);

样品使用方法:

private File toFile(Uri uri) throws IOException {
        String displayName = "";
        Cursor cursor = getContentResolver().query(uri, null, null, null, null);

        if(cursor != null && cursor.moveToFirst()){
            try {
                displayName = cursor.getString(cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME));
            }finally {
                cursor.close();
            }
        }

        File file =  File.createTempFile(
                FilenameUtils.getBaseName(displayName),
                "."+FilenameUtils.getExtension(displayName)
        );
        InputStream inputStream = getContentResolver().openInputStream(uri);
        FileUtils.copyInputStreamToFile(inputStream, file);
        return file;
    }

编辑:对不起，我之前应该测试得更好。这应该可以工作:

new File(new URI(androidURI.toString()));

URI是java.net.URI。

最好的解决方案

创建一个简单的FileUtil类，用于创建、复制和重命名文件

我使用了uri.toString()和uri.getPath()，但不适合我。 我终于找到了这个解。

import android.content.Context;
import android.database.Cursor;
import android.net.Uri;
import android.provider.OpenableColumns;
import android.util.Log;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class FileUtil {
    private static final int EOF = -1;
    private static final int DEFAULT_BUFFER_SIZE = 1024 * 4;

    private FileUtil() {

    }

    public static File from(Context context, Uri uri) throws IOException {
        InputStream inputStream = context.getContentResolver().openInputStream(uri);
        String fileName = getFileName(context, uri);
        String[] splitName = splitFileName(fileName);
        File tempFile = File.createTempFile(splitName[0], splitName[1]);
        tempFile = rename(tempFile, fileName);
        tempFile.deleteOnExit();
        FileOutputStream out = null;
        try {
            out = new FileOutputStream(tempFile);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        if (inputStream != null) {
            copy(inputStream, out);
            inputStream.close();
        }

        if (out != null) {
            out.close();
        }
        return tempFile;
    }

    private static String[] splitFileName(String fileName) {
        String name = fileName;
        String extension = "";
        int i = fileName.lastIndexOf(".");
        if (i != -1) {
            name = fileName.substring(0, i);
            extension = fileName.substring(i);
        }

        return new String[]{name, extension};
    }

    private static String getFileName(Context context, Uri uri) {
        String result = null;
        if (uri.getScheme().equals("content")) {
            Cursor cursor = context.getContentResolver().query(uri, null, null, null, null);
            try {
                if (cursor != null && cursor.moveToFirst()) {
                    result = cursor.getString(cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME));
                }
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                if (cursor != null) {
                    cursor.close();
                }
            }
        }
        if (result == null) {
            result = uri.getPath();
            int cut = result.lastIndexOf(File.separator);
            if (cut != -1) {
                result = result.substring(cut + 1);
            }
        }
        return result;
    }

    private static File rename(File file, String newName) {
        File newFile = new File(file.getParent(), newName);
        if (!newFile.equals(file)) {
            if (newFile.exists() && newFile.delete()) {
                Log.d("FileUtil", "Delete old " + newName + " file");
            }
            if (file.renameTo(newFile)) {
                Log.d("FileUtil", "Rename file to " + newName);
            }
        }
        return newFile;
    }

    private static long copy(InputStream input, OutputStream output) throws IOException {
        long count = 0;
        int n;
        byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
        while (EOF != (n = input.read(buffer))) {
            output.write(buffer, 0, n);
            count += n;
        }
        return count;
    }
}

在代码中使用FileUtil类

try {
         File file = FileUtil.from(MainActivity.this,fileUri);
         Log.d("file", "File...:::: uti - "+file .getPath()+" file -" + file + " : " + file .exists());

  } catch (IOException e) {
          e.printStackTrace();
  }

你可以使用这个函数从uri中获取文件在新的android和旧的

fun getFileFromUri(context: Context, uri: Uri?): File? {
    uri ?: return null
    uri.path ?: return null

    var newUriString = uri.toString()
    newUriString = newUriString.replace(
        "content://com.android.providers.downloads.documents/",
        "content://com.android.providers.media.documents/"
    )
    newUriString = newUriString.replace(
        "/msf%3A", "/image%3A"
    )
    val newUri = Uri.parse(newUriString)

    var realPath = String()
    val databaseUri: Uri
    val selection: String?
    val selectionArgs: Array<String>?
    if (newUri.path?.contains("/document/image:") == true) {
        databaseUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI
        selection = "_id=?"
        selectionArgs = arrayOf(DocumentsContract.getDocumentId(newUri).split(":")[1])
    } else {
        databaseUri = newUri
        selection = null
        selectionArgs = null
    }
    try {
        val column = "_data"
        val projection = arrayOf(column)
        val cursor = context.contentResolver.query(
            databaseUri,
            projection,
            selection,
            selectionArgs,
            null
        )
        cursor?.let {
            if (it.moveToFirst()) {
                val columnIndex = cursor.getColumnIndexOrThrow(column)
                realPath = cursor.getString(columnIndex)
            }
            cursor.close()
        }
    } catch (e: Exception) {
        Log.i("GetFileUri Exception:", e.message ?: "")
    }
    val path = realPath.ifEmpty {
        when {
            newUri.path?.contains("/document/raw:") == true -> newUri.path?.replace(
                "/document/raw:",
                ""
            )
            newUri.path?.contains("/document/primary:") == true -> newUri.path?.replace(
                "/document/primary:",
                "/storage/emulated/0/"
            )
            else -> return null
        }
    }
    return if (path.isNullOrEmpty()) null else File(path)
}

要正确地使用context uri获取文件， 感谢来自@Mohsents， @Bogdan Kornev， @CommonsWare， @Juan Camilo Rodriguez的回答Durán;

我从uri中创建了一个inputStream，并使用这个iStream创建了一个临时文件，最后我能够从这个文件中提取uri和路径。

fun createFileFromContentUri(fileUri : Uri) : File{

    var fileName : String = ""

    fileUri.let { returnUri ->
        requireActivity().contentResolver.query(returnUri,null,null,null)
    }?.use { cursor ->
        val nameIndex = cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME)
        cursor.moveToFirst()
        fileName = cursor.getString(nameIndex)
    }
    
    //  For extract file mimeType
    val fileType: String? = fileUri.let { returnUri ->
        requireActivity().contentResolver.getType(returnUri)
    }

    val iStream : InputStream = requireActivity().contentResolver.openInputStream(fileUri)!!
    val outputDir : File = context?.cacheDir!!
    val outputFile : File = File(outputDir,fileName)
    copyStreamToFile(iStream, outputFile)
    iStream.close()
    return  outputFile
}

fun copyStreamToFile(inputStream: InputStream, outputFile: File) {
    inputStream.use { input ->
        val outputStream = FileOutputStream(outputFile)
        outputStream.use { output ->
            val buffer = ByteArray(4 * 1024) // buffer size
            while (true) {
                val byteCount = input.read(buffer)
                if (byteCount < 0) break
                output.write(buffer, 0, byteCount)
            }
            output.flush()
        }
    }
}

添加onActivityResult，获取docx或pdf文件

var imageUriPath = ""
imageUriPath =
  if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
    val split = (imageUri.path ? : "").split(":") //split the path.
    split[1]
  } else {
    imageUri.path ? : ""
  }
val file = File(imageUriPath)