所以我想在android中选择一个文件，选择后我想将字节读入字节数组。但是，当我尝试读取字节时，出现错误：java.io.FileNotFoundException: /document/1358 (No such file or directory)。这是我的代码：
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
switch(requestCode) {
case ACTIVITY_CHOOSE_FILE: {
if (resultCode == RESULT_OK) {
Uri uri = data.getData();
String filePath = uri.getPath();
File file = new File(filePath);
int size = (int) file.length();
byte[] bytes = new byte[size];
try {
BufferedInputStream buf = new BufferedInputStream(new FileInputStream(file)); //error??
buf.read(bytes, 0, bytes.length);
buf.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
这是我打开意图的代码：
Intent chooseFile;
Intent intent;
chooseFile = new Intent(Intent.ACTION_GET_CONTENT);
chooseFile.setType("*/*");
intent = Intent.createChooser(chooseFile, "Choose a file");
startActivityForResult(intent, ACTIVITY_CHOOSE_FILE);
从onActivityResult获取uri，然后使用此util类获取文件的相对路径：
public class RealPathUtil {
public static String getRealPath(Context context, Uri fileUri) {
String realPath;
// SDK < API11
if (Build.VERSION.SDK_INT < 11) {
realPath = RealPathUtil.getRealPathFromURI_BelowAPI11(context, fileUri);
}
// SDK >= 11 && SDK < 19
else if (Build.VERSION.SDK_INT < 19) {
realPath = RealPathUtil.getRealPathFromURI_API11to18(context, fileUri);
}
// SDK > 19 (Android 4.4) and up
else {
realPath = RealPathUtil.getRealPathFromURI_API19(context, fileUri);
}
return realPath;
}
@SuppressLint("NewApi")
public static String getRealPathFromURI_API11to18(Context context, Uri contentUri) {
String[] proj = {MediaStore.Images.Media.DATA};
String result = null;
CursorLoader cursorLoader = new CursorLoader(context, contentUri, proj, null, null, null);
Cursor cursor = cursorLoader.loadInBackground();
if (cursor != null) {
int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
cursor.moveToFirst();
result = cursor.getString(column_index);
cursor.close();
}
return result;
}
public static String getRealPathFromURI_BelowAPI11(Context context, Uri contentUri) {
String[] proj = {MediaStore.Images.Media.DATA};
Cursor cursor = context.getContentResolver().query(contentUri, proj, null, null, null);
int column_index = 0;
String result = "";
if (cursor != null) {
column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
cursor.moveToFirst();
result = cursor.getString(column_index);
cursor.close();
return result;
}
return result;
}
/**
* Get a file path from a Uri. This will get the the path for Storage Access
* Framework Documents, as well as the _data field for the MediaStore and
* other file-based ContentProviders.
*
* @param context The context.
* @param uri The Uri to query.
* @author paulburke
*/
@SuppressLint("NewApi")
public static String getRealPathFromURI_API19(final Context context, final 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;
}
/**
* 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());
}}
如果您有类似文件：
File file = new File(RealPathUtil.getRealPath(this, data.getData()));
您可以使用此方法获取字节数组：
private byte[] getDataFromFile(File file) {
int size = (int) file.length();
byte[] bytes = new byte[size];
try {
BufferedInputStream buf = new BufferedInputStream(new FileInputStream(file));
buf.read(bytes, 0, bytes.length);
buf.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return bytes;
}