I am using xamarin forms and build sample app. The app has few fields and take image function. When user take an image, the image get saved in phone gallery and get renamed to data from fields.
I have a notes field. In notes field user can enter some text and characters. I don't want to include data from note fields to rename image.
What I want is to get the user input from notes field and save in image comments. (Please see image below).
image comment
My first question is it possible to do that. So user fill some fields, take picture, and whatever user type in notes field; it can get saved in imagedetails->comments.
This is code to save image and rename to some data input fields.
I am using jamesmontemagno/MediaPlugin plugin to take images.
https://github.com/jamesmontemagno/MediaPlugin
private async void Take_Photo_Button_Clicked(object sender, EventArgs e)
{
await CrossMedia.Current.Initialize();
if (!CrossMedia.Current.IsCameraAvailable || !CrossMedia.Current.IsTakePhotoSupported)
{
await DisplayAlert("No Camera", ":( No camera available.", "OK");
return;
}
var file = await CrossMedia.Current.TakePhotoAsync(new Plugin.Media.Abstractions.StoreCameraMediaOptions
{
SaveToAlbum = true,
//Directory = "Sample",
Name = jobnoentry.Text + "-" + Applicationletter + "-" + signnoentry.Text + "-" + Phototypeentry,
});
if (file == null)
return;
MainImage.Source = ImageSource.FromStream(() =>
{
var stream = file.GetStream();
return stream;
});
You can see I assign Name of image to some data fields. But how i can add notes to annotate the image and have them in image comments.
Hope you all understand my question.
It's not clear what file type is the image being stored as. Is it a .png? a .jpeg? The library's example seems to indicate it stores JPEG files.
If that's the case, look into editing EXIF data. i.e. https://developer.xamarin.com/api/type/Android.Media.ExifInterface/
Related
I am using Realm MongoDB for my android app, and I have a problem:
I have different users in my app, and each user has his "cards". The partition of each user's cards is:
"Card=userID".
So, I want to be able to send a card from one user to the other. I do it via a link that includes userID and specific cardID.
So my code looks something like:
Realm.init(this);
mainApp = new App(new AppConfiguration.Builder(APP_ID).defaultSyncErrorHandler((session, error) ->
Log.e("TAG()", "Sync error: ${error.errorMessage}")
).build());
//TEMP CODE
String partition = "Card=611d7n582w36796ce34af106"; //test partition of another user
if(mainApp.currentUser() != null) {
SyncConfiguration config = new SyncConfiguration.Builder(
mainApp.currentUser(),
partition)
.build();
Realm realmLinkCard = Realm.getInstance(config);
Log.d(TAG, "onCreate: cards found- " + realmLinkCard.where(Card.class).findAll().size());
}
The last log always shows 0. I know there are cards for sure because if the user that created the corresponding partition is signed in then it does find the cards.
permissions are set to true for both read and write for the whole sync.
What can the problem be?
You cannot access a Realm by a user who has a different partition.
Instead you can create a mongodb function and call it from your user.
Make your function here:
Check here on How to create a function
And call it by checking here on How to call a function from client
Quick example of a realm function:
exports = async function funcName(partition) {
const cluster = context.services.get('myclustername');
const mycollection = cluster.db('mydbname').collection('mycollectionname');
let result = [];
try {
result = mycollection.findOne({
_partition: partition,
});
} catch (e) {
result.push(e);
return result;
}
return result;
};
To call it, please see above for the documentation as I'm not an Android developper.
I am using sqlflite flutter package to manage a small database for my app, there is a table where I have some urls for few images from the internet , but I need to save them and use the files instead of urls to show this images later. I mean I want to do something like this :
bool internet
internet ? Image.network('the_url') : Image.assets("path to image in my assets folder")
so, is there any way to fetch images from urls and save it to be able to access it later?
You can download the image with NetworkAssetBundle and convert to Unint8List
final ByteData imageData = await NetworkAssetBundle(Uri.parse("YOUR_URL")).load("");
final Uint8List bytes = imageData.buffer.asUint8List();
Then you can load it through Image.memory() widget
Image.memory(bytes);
You can store that data in sqflite and retrive when needed
You can use the path_provider package to download from internet and save it locally. Then you can load from local asset if available. Otherwise it can download from the internet also.
Future<String?> loadPath() async {
var dir = await getApplicationDocumentsDirectory();
String dirName = widget.url!.substring(87);
file = File("${dir.path}/$dirName");
if (file.existsSync() == true && _isDownloadingPDF == false) {
// debugPrint('file.path returned');
return file.path;
} else {
return null;
}
}
Have you tried https://pub.dev/packages/cached_network_image?
It seems like this package will fulfil your requirements.
I'm using nativescript-imagepicker plugin to select images from phone gallery. One of the things this plugin allows me to get, is the path to the file.
I need to be able to upload this selected file to a server, using form data. For that i need to create a file object first.
How can i use a file path, to create a file object?
For uploading images from the photo gallery I would highly suggest using Nativescsript background http. To upload the images to the server you will have to save them within the app so that they can be uploaded. I followed the example shown here Upload example.
Once you have saved the images locally if you want additional data you will need to use multipartUpload and construct a request that would look something like this.
let BackgroundHTTP = require('nativescript-background-http')
let session = BackgroundHTTP.session('some unique session id')
let request: {
url: 'your.url.to/upload/images',
method: 'POST',
headers: {
'Content-Type': 'application/octet-stream'
}
description: 'Uploading local images to the server'
}
//photos should have at least the filename from when you saved it locally.
let params = []
photos.forEach(photo => {
params.push({name: photo.name, filename: photo.filename, value: 'ANY STRING DATA YOU NEED'})
}
let task = session.multipartUpload(params, request)
task.on('progress', evt => {
console.log('upload progress: ' + ((evt.currentBytes / evt.totalBytes) * 100).toFixed(1) + '%')
}
task.on('error', evt => {
console.log('upload error')
console.log(evt)
}
task.on('complete', evt => {
//this does not mean the server had a positive response
//but the images hit the server.
// use evt.responseCode to determine the status of request
console.log('upload complete, status: ' + evt.responseCode)
}
I have developed an app to take a photo from the phone camera. But now I need to store the image to the phone memory into a folder created by me.
I have tried this:
var filename = Titanium.Filesystem.resourcesDirectory + "/newImageFile.jpg";
var imageFile = Titanium.Filesystem.getFile(filename);
imageFile.write(capturedImg);
But it does not apear in the gallery. How can I store the image to the phone memory and how can I create a costume folder in the phone memory to store the image?
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info
{
NSData *imageData = [info objectForKey:UIImagePickerControllerOriginalImage];
if(picker.sourceType==UIImagePickerControllerSourceTypeCamera)
{
//to save camera roll
[[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
[PHAssetChangeRequest creationRequestForAssetFromImage:image];
} completionHandler:nil];
}
}
This will save image in camera roll which is taken by you
This Will Create Photo Album and save into this album.
I came up with this singleton class to handle it:
import Photos
class CustomPhotoAlbum {
static let albumName = "Titanium"
static let sharedInstance = CustomPhotoAlbum()
var assetCollection: PHAssetCollection!
init() {
func fetchAssetCollectionForAlbum() -> PHAssetCollection! {
let fetchOptions = PHFetchOptions()
fetchOptions.predicate = NSPredicate(format: "title = %#", CustomPhotoAlbum.albumName)
let collection = PHAssetCollection.fetchAssetCollectionsWithType(.Album, subtype: .Any, options: fetchOptions)
if let firstObject: AnyObject = collection.firstObject {
return collection.firstObject as! PHAssetCollection
}
return nil
}
if let assetCollection = fetchAssetCollectionForAlbum() {
self.assetCollection = assetCollection
return
}
PHPhotoLibrary.sharedPhotoLibrary().performChanges({
PHAssetCollectionChangeRequest.creationRequestForAssetCollectionWithTitle(CustomPhotoAlbum.albumName)
}) { success, _ in
if success {
self.assetCollection = fetchAssetCollectionForAlbum()
}
}
}
func saveImage(image: UIImage) {
if assetCollection == nil {
return // If there was an error upstream, skip the save.
}
PHPhotoLibrary.sharedPhotoLibrary().performChanges({
let assetChangeRequest = PHAssetChangeRequest.creationRequestForAssetFromImage(image)
let assetPlaceholder = assetChangeRequest.placeholderForCreatedAsset
let albumChangeRequest = PHAssetCollectionChangeRequest(forAssetCollection: self.assetCollection)
albumChangeRequest.addAssets([assetPlaceholder])
}, completionHandler: nil)
}
}
When you first instantiate the class, the custom album will be created if it doesn't already exist. You can save an image like this:
CustomPhotoAlbum.sharedInstance.saveImage(image)
NOTE: The CustomPhotoAlbum class assumes the app already has permission to access the Photo Library. Dealing with the permissions is a bit outside the scope of this question/answer. So make sure PHPhotoLibrary.authorizationStatus() == .Authorize before you use it. And request authorization if necessary.
Background
I've noticed a weird column for MediaStore.Images.ImageColumns called "MINI_THUMB_MAGIC" .
the documentation says just that :
The mini thumb id.
Type: INTEGER
Constant Value: "mini_thumb_magic"
The question
my guess is that this field is related to MediaStore.Images.Thumbnails .
Is it correct ? if not, what is this and how do you use it?
if it is correct , i have other questions related to it:
Is it a mini sized image of the original one? does it use the same aspect ratio or does it do center-cropping on it?
how come the size of "MICRO" is square (96 x 96) and the size of "MINI" is a non-square rectangle ( 512 x 384 ) ?
How do you use it? My guess is that it's done by using "THUMB_DATA", which is a blob, so you use it like this, but then what is the purpose of using "getThumbnail" if you already have this field?
does it get a rotated thumbnail in case the orientation value is not 0 ? meaning that if I wish to show it, I won't need to rotate the image?
Is it possible to do a query of the images together with their thumbnails? maybe using inner join?
Is it available for all Android devices and versions?
Why is it even called "magic" ? Is it because it's also available for videos (and for some reason doesn't exist for music, as it could be the album's cover photo, for example) ?
Check this file: https://github.com/android/platform_packages_providers_mediaprovider/blob/master/src/com/android/providers/media/MediaThumbRequest.java in the Android source code. This value is some magic number which allows to determine if the thumbnail is still valid. I didn't investigate that file further, but it should be no bit issue to dive deeper.
To your questions:
No, no mini-sized image
Well, I guess it's a definition by Google who want to have a square thumbnail for some lists, where only very small previews should be visible and where many items should fit on the screen and there's another thumbnail format where the images are bigger...
I don't know that, but according to Google's doc, one (THUMB_DATA) is only some raw byte array of the thumbnail (dunno in which format) and the other one (getThumbnail) retrieves a full-fledged bitmap object...
don't know
don't know
I guess so, as it's part of AOSP source code.
The word "magic" is often used for some kind of identifier. There are "magic packets" who can wake up a computer from sleep or shutdown over the network, there are magic numbers on hard disks, where some sectors (e.g. the MBR) has the hexadecimal values AA 55 on its last two byte positions, there are also magic numbers in image files which help software packages determine the image type (e.g. GIF files begin with GIF89a or GIF87a (ASCII), JPEG files begin with FF D8 hexadecimal) and there are many, many more examples. So, magic numbers are a very common term here :-)
According to the source code at the following URL, the Magic Number is the Id of the original image * a constant. That value is then used to check for a long int. If the int isn't as expected, it's considered out of sync with the image media.
http://grepcode.com/file/repo1.maven.org/maven2/org.robolectric/android-all/4.4_r1-robolectric-0/android/media/MiniThumbFile.java#MiniThumbFile.getMagic%28long%29
// Get the magic number for the specified id in the mini-thumb file.
// Returns 0 if the magic is not available.
public synchronized long getMagic(long id) {
// check the mini thumb file for the right data. Right is
// defined as having the right magic number at the offset
// reserved for this "id".
RandomAccessFile r = miniThumbDataFile();
if (r != null) {
long pos = id * BYTES_PER_MINTHUMB;
FileLock lock = null;
try {
mBuffer.clear();
mBuffer.limit(1 + 8);
lock = mChannel.lock(pos, 1 + 8, true);
// check that we can read the following 9 bytes
// (1 for the "status" and 8 for the long)
if (mChannel.read(mBuffer, pos) == 9) {
mBuffer.position(0);
if (mBuffer.get() == 1) {
return mBuffer.getLong();
}
}
} catch (IOException ex) {
Log.v(TAG, "Got exception checking file magic: ", ex);
} catch (RuntimeException ex) {
// Other NIO related exception like disk full, read only channel..etc
Log.e(TAG, "Got exception when reading magic, id = " + id +
", disk full or mount read-only? " + ex.getClass());
} finally {
try {
if (lock != null) lock.release();
}
catch (IOException ex) {
// ignore it.
}
}
}
return 0;
}
I got the runtime exception when trying to get the original Id of a thumbnail by looking up the thumbnail's path. (BTW, the disk isn't full and it's not read-only.)
It's a bit strange parameter...
While exploring the Gallery source code,
noticed that the value is being read from the cursor, but then is Never used:
#Override
protected BaseImage loadImageFromCursor(Cursor cursor) {
long id = cursor.getLong(INDEX_ID);
String dataPath = cursor.getString(INDEX_DATA_PATH);
long dateTaken = cursor.getLong(INDEX_DATE_TAKEN);
if (dateTaken == 0) {
dateTaken = cursor.getLong(INDEX_DATE_MODIFIED) * 1000;
}
// here they read it ====>>
long miniThumbMagic = cursor.getLong(INDEX_MINI_THUMB_MAGIC);
int orientation = cursor.getInt(INDEX_ORIENTATION);
String title = cursor.getString(INDEX_TITLE);
String mimeType = cursor.getString(INDEX_MIME_TYPE);
if (title == null || title.length() == 0) {
title = dataPath;
}
// and not use at all ==>>>
return new Image(this, mContentResolver, id, cursor.getPosition(),
contentUri(id), dataPath, mimeType, dateTaken, title,
orientation);
}
Maybe it was used on the previous APIs.
ref: https://android.googlesource.com/platform/packages/apps/Gallery/+/android-8.0.0_r12/src/com/android/camera/gallery/ImageList.java?autodive=0%2F%2F.
and videos list:
https://android.googlesource.com/platform/packages/apps/Gallery/+/android-8.0.0_r12/src/com/android/camera/gallery/VideoList.java?autodive=0%2F%2F