Array of images to store in cache? - android

I am working with the cards (cardView) and trying to store the images inside the array (array to string; store that in cache and when required unpack back to array). My question is: what is the most convenient way to store the images in an array?
Store the bitmaps (bitmapToString etc)? Turn the bitmaps (I get the images from the gallery and camera) into URIs? Absolute paths?
The number of images is small (3-4), so, I guess, there's no need in a DB.

Android Bitmap objects are not good candidates for storing in Java arrays - they are very large objects so you run the risk of an OutOfMemoryException. It is easy to create a memory leak if you are not careful.
If you have to get some photos from the gallery as Bitmap and retain them in your app, one of the patterns that is normally used is writing the Bitmap to the app's internal storage (covered here.
If you need a reference to the stored photo, you can save the filename or a Uri that represents the photo or image.
Then the problem of loading Bitmaps etc. into an ImageView is solved with libraries like Picasso or Glide. You can use these to load from the local file system, or from online.

Related

Android: Best approach for saving images in Room database

I have a room data base with 2 entities that save images as bitmaps. But I've encountered a problem where if I try to save images that are larges(1.5MB+) which are most of the pictures taken by modern smartphones, when I try to retrieve it, the app crushes because it can only have 1MB of data.
I've tried to compress the bitmap before inserting it using https://github.com/zetbaitsu/Compressor, but it's complicated because you can't limit the size, and bitmaps are larger than what they are on files.
So I thought about 3 approaches for saving the images, an my question is which one is the best(and easy to implement), or whether there is a better approach than those.
compressing the bitmaps before saving - which is complicated and didn't work for very large files.
saving the Uri in the database instead, but if you delete the image from the phone than the image isn't saved in the database which is unexpected behavior for the user.
saving the image in storage than saving the Uri to the image - but it requires asking for permission to WRITE_EXTERNAL_STORAGE.
Thanks a lot in advance!

Android: Working with images and SQLite [duplicate]

This question already has answers here:
What is the best way to store the image in the memory of app?
(4 answers)
Closed 6 years ago.
I'd like to be able to programmatically work with Images, ImageViews, Drawables, and SQLite blobs (byte arrays). I inevitably want to be able to have a program that lets me acquire images from the Gallery app or something similar (ie camera), and then place them in a gallery construct within my app and work with them from there. Storing them in SQLite database's as needed.
I haven't come across anything that works. Much of it is deprecated. I have a simple project that is working with text in a SQLite database, and am now trying images.
If you can show or send me someplace that shows how to work with these constructs that would be great. Though to be more specific for this thread I'll state a few things I'd like to do:
Converting Drawables to ImageViews and converting Drawables to SQLite blobs.
Acquiring images from outside the program and placing them in the Drawables section.
Best constructs for working with images.
Thanks,
convert a image to byte[] and easy to store SQlite db
Don't store images in SQLite, instead of saving images save their path into SQLite, and later you can load image from their path.
and if you are loading images from web then you can use Universal Image Loader. It will display and store images in device memory and you can load images offline anytime with same url.
Instead of saving image as blob, save the image url. Or save it in external file in sd card or phone memory.
To save it in a link,
When the user selects an image from gallery. Call the upload image function ( it can be a BoundService ). You can find it by googling it.
When the upload image is successfull, ull get the image url in Json.
Just save that image link in your sqlite database.
Hope it helps.

How to store large Data in application?

I want to make image backup through my Application what is the best way for storing large amount of data . I tried to save image in sqlite database it worked fine for small amount of data in case of large amount it shows MemoryOutOfBoundExceptions after increasing the Heep size(android:largeHeap="true").
please help me guys .
If you want to save only image or any file try to save only path of that file in database.After that you can get file path by normal SQL query and access file from file path.
Instead of Storing Large data in Application you have to store it DataBase so it will speed up your Application and you have no Exception produce like OutOfMemoryException in your Application.
You don't store images in databases, that makes the database huge and slows it down. Store the images to disk and store the path to the file in the database. This will make the database a lot lighter and faster.
If you're developing for Android, i'd also recommend using something like Picasso, Fresco or Glide to display your images too. They cache the image and use memory efficiently when doing operations like scaling images.

How to create bitmaps quicker in Android?

I am working on an Android application where I am getting my data which includes images stored as blobs from a database, and then once I get this data in my application, I am transforming all of these into bitmaps, and storing the data in ArrayList for later use. When doing this for two dozen images it takes around 8 seconds; how can I create the bitmaps quicker. The images vary in height. In a for loop I am turning the image string into a byte array and then using BitmapFactory.decodeByteArray. I am also using options.inSampleSize = 4.
Read images from database and store into local cache memory and then you read images from cache memory,it's efficient way of displaying bitmap.
Refer this link:
https://developer.android.com/training/displaying-bitmaps/cache-bitmap.html

Which method should I use to store and retrive images for an android application?

I am developing an application that requires me to retrieve multiple images from a Cache database and then display them on an Application.
At the moment i write the images to binary array's and then convert them to bitmap images on the application, but the Base64 string is about 30% larger that the actual image.
What encoding method should i use to reduce the overhead involved in storing these images?
You can store the images in the SDCard, in the device cache, or in a database. Not sure which you mean but here are some guides.
This post explains how to store an image in any location on the sdcard:
Save bitmap to location
This one explains how to store in the device cache partition: Android, Saving and loading a bitmap in cache from different activities
And this guide explains saving and retrieving bitmaps to/from a database: http://www.tutorialforandroid.com/2009/10/how-to-insert-image-data-to-sqlite.html

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