我创建了一个将文件上传到 PHP 服务器的程序。 它看起来像这样:

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

    private static final int PICK_FILE_REQUEST = 1;
    private static final String TAG = MainActivity.class.getSimpleName();
    private String selectedFilePath;
    private String SERVER_URL = "http://192.168.0.29/aji/AndroidFileUpload/UploadToServer.php";
    ImageView ivAttachment;
    Button bUpload;
    TextView tvFileName;
    ProgressDialog dialog;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ivAttachment = (ImageView) findViewById(R.id.ivAttachment);
        bUpload = (Button) findViewById(R.id.b_upload);
        tvFileName = (TextView) findViewById(R.id.tv_file_name);
        ivAttachment.setOnClickListener(this);
        bUpload.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        if(v== ivAttachment){

            //on attachment icon click
            showFileChooser();
        }
        if(v== bUpload){

            //on upload button Click
            if(selectedFilePath != null){
                dialog = ProgressDialog.show(MainActivity.this,"","Uploading File...",true);

                new Thread(new Runnable() {
                    @Override
                    public void run() {
                        //creating new thread to handle Http Operations
                        uploadFile(selectedFilePath);
                    }
                }).start();
            }else{
                Toast.makeText(MainActivity.this,"Please choose a File First",Toast.LENGTH_SHORT).show();
            }

        }
    }

    private void showFileChooser() {
        Intent intent = new Intent();
        //sets the select file to all types of files
        intent.setType("file/*");
        //allows to select data and return it
        intent.setAction(Intent.ACTION_GET_CONTENT);
        //starts new activity to select file and return data
        startActivityForResult(Intent.createChooser(intent,"Choose File to Upload.."),PICK_FILE_REQUEST);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if(resultCode == Activity.RESULT_OK){
            if(requestCode == PICK_FILE_REQUEST){
                if(data == null){
                    //no data present
                    return;
                }


                Uri selectedFileUri = data.getData();
                selectedFilePath = FilePath.getPath(this,selectedFileUri);
                Log.i(TAG,"Selected File Path:" + selectedFilePath);

                if(selectedFilePath != null && !selectedFilePath.equals("")){
                    tvFileName.setText(selectedFilePath);
                }else{
                    Toast.makeText(this,"Cannot upload file to server",Toast.LENGTH_SHORT).show();
                }
            }
        }
    }

    //android upload file to server
    public int uploadFile(final String selectedFilePath){

        int serverResponseCode = 0;

        HttpURLConnection connection;
        DataOutputStream dataOutputStream;
        String lineEnd = "\r\n";
        String twoHyphens = "--";
        String boundary = "*****";


        int bytesRead,bytesAvailable,bufferSize;
        byte[] buffer;
        int maxBufferSize = 1 * 1024 * 1024;
        File selectedFile = new File(selectedFilePath);


        String[] parts = selectedFilePath.split("/");
        final String fileName = parts[parts.length-1];

        if (!selectedFile.isFile()){
            dialog.dismiss();

            runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    tvFileName.setText("Source File Doesn't Exist: " + selectedFilePath);
                }
            });
            return 0;
        }else{
            try{
                FileInputStream fileInputStream = new FileInputStream(selectedFile);
                URL url = new URL(SERVER_URL);
                connection = (HttpURLConnection) url.openConnection();
                connection.setDoInput(true);//Allow Inputs
                connection.setDoOutput(true);//Allow Outputs
                connection.setUseCaches(false);//Don't use a cached Copy
                connection.setRequestMethod("POST");
                connection.setRequestProperty("Connection", "Keep-Alive");
                connection.setRequestProperty("ENCTYPE", "multipart/form-data");
                connection.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + boundary);
                connection.setRequestProperty("uploaded_file",selectedFilePath);

                //creating new dataoutputstream
                dataOutputStream = new DataOutputStream(connection.getOutputStream());

                //writing bytes to data outputstream
                dataOutputStream.writeBytes(twoHyphens + boundary + lineEnd);
                dataOutputStream.writeBytes("Content-Disposition: form-data; name=\"uploaded_file\";filename=\""
                        + selectedFilePath + "\"" + lineEnd);

                dataOutputStream.writeBytes(lineEnd);

                //returns no. of bytes present in fileInputStream
                bytesAvailable = fileInputStream.available();
                //selecting the buffer size as minimum of available bytes or 1 MB
                bufferSize = Math.min(bytesAvailable,maxBufferSize);
                //setting the buffer as byte array of size of bufferSize
                buffer = new byte[bufferSize];

                //reads bytes from FileInputStream(from 0th index of buffer to buffersize)
                bytesRead = fileInputStream.read(buffer,0,bufferSize);

                //loop repeats till bytesRead = -1, i.e., no bytes are left to read
                while (bytesRead > 0){
                    //write the bytes read from inputstream
                    dataOutputStream.write(buffer,0,bufferSize);
                    bytesAvailable = fileInputStream.available();
                    bufferSize = Math.min(bytesAvailable,maxBufferSize);
                    bytesRead = fileInputStream.read(buffer,0,bufferSize);
                }

                dataOutputStream.writeBytes(lineEnd);
                dataOutputStream.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);

                serverResponseCode = connection.getResponseCode();
                String serverResponseMessage = connection.getResponseMessage();

                Log.i(TAG, "Server Response is: " + serverResponseMessage + ": " + serverResponseCode);

                //response code of 200 indicates the server status OK
                if(serverResponseCode == 200){
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            tvFileName.setText("File Upload completed.\n\n You can see the uploaded file here: \n\n" + "http://coderefer.com/extras/uploads/"+ fileName);
                        }
                    });
                }

                //closing the input and output streams
                fileInputStream.close();
                dataOutputStream.flush();
                dataOutputStream.close();



            } catch (FileNotFoundException e) {
                e.printStackTrace();
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        Toast.makeText(MainActivity.this,"File Not Found",Toast.LENGTH_SHORT).show();
                    }
                });
            } catch (MalformedURLException e) {
                e.printStackTrace();
                Toast.makeText(MainActivity.this, "URL error!", Toast.LENGTH_SHORT).show();

            } catch (IOException e) {
                e.printStackTrace();
                Toast.makeText(MainActivity.this, "Cannot Read/Write File!", Toast.LENGTH_SHORT).show();
            }
            dialog.dismiss();
            return serverResponseCode;
        }

    }
}

对于文件路径:

public class FilePath {

    /**
     * Method for return file path of Gallery image/ Document / Video / Audio
     *
     * @param context
     * @param uri
     * @return path of the selected image file from gallery
     */
    @TargetApi(Build.VERSION_CODES.KITKAT)
    public static String getPath(final Context context, final Uri uri) {

        // check here to KITKAT or new version
        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];
                }
            }
            // 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;
    }

    /**
     * Get the value of the data column for this Uri. This is useful for
     * MediaStore Uris, and other file-based ContentProviders.
     *
     * @param context
     *            The context.
     * @param uri
     *            The Uri to query.
     * @param selection
     *            (Optional) Filter used in the query.
     * @param selectionArgs
     *            (Optional) Selection arguments used in the query.
     * @return The value of the _data column, which is typically a file path.
     */
    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;
    }

    /**
     * @param uri
     *            The Uri to check.
     * @return Whether the Uri authority is ExternalStorageProvider.
     */
    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());
    }
}

当我在 Android IceCream Sandwich 上运行它时它工作正常。 但是当我在Android marshmallow上运行时，无法点击文件。

它看起来像这样:

最佳答案

file/* 不是有效的 MIME 类型。如果你想支持任何类型的文件，你应该使用 */*。您看到的文件无法选择，因为它们的 MIME 类型不正确。

随着virtual files in Android 7.0的引入(没有字节流的文件因此不能直接上传)，你应该绝对添加CATEGORY_OPENABLE符合您的 Intent :

private void showFileChooser() {
    Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
    //sets the select file to all types of files
    intent.setType("*/*");
    // Only get openable files
    intent.addCategory(Intent.CATEGORY_OPENABLE);
    //starts new activity to select file and return data
    startActivityForResult(Intent.createChooser(intent,
        "Choose File to Upload.."),PICK_FILE_REQUEST);
}

关于android - 无法在android棉花糖上选择文件，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/39323382/