Save image android java

Пишем функцию сохранения картинок на SD-карту

В процессе написания приложения для андроида у меня возникла задача сохранять произвольное изображение в файл на флешке. В этой статье я опишу, как я решил эту проблему, какие трудности встретились мне в процессе, и как они были решены. Хотелось бы отдельно отметить, что я .NET программист, судьба занесла меня в Java-мир только из-за необходимости создания небольших по размеру (поэтому monodroid сразу нет) и довольно простых с точки зрения интерфейса андроид-приложений. Это означает, что я тоже только учусь, а значит буду рад любым советом и замечаниям профессионалов.

Итак, предположим, что у нас есть ImageView, в котором содержится картинка, необходимая нам в виде файла. Первый же вопрос — куда сохранять эту картинку?

Самый правильный и гуглом одобренный подход будет сохранять картинку в папку кэша специально выделенную для вашей аппликации.
Получить абсолютный путь к ней можно вызовом функции:

Данная папка очищается при деинсталляции приложения, кроме того ее размер отслеживается системой, и при нехватке места внутренней памяти, файлы оттуда будут автоматически удалены андроидом.

Есть у данного решения и минусы. Самый главный — папка кэша приложения содержится во внутренней памяти устройства, которой вечно не хватает. Рекомендуется сохранять там лишь временные и не очень большие файлы, сохранение большого количества тяжелых картинок здесь нежелательно.

Лучше воспользоваться папкой кэша приложения на SD-карте, путь к которой можно получить функцией:

Данная папка тоже будет очищена при деинсталляции приложения, но ее размер не отслеживается системой, поэтому перед сохранением туда файлов, ее состояние желательно проверять командой:

В моем случае по совокупности разных факторов оба стандартных решения показались мне неоптимальными, поэтому я просто сохраняю файлы в корне SD-карты, путь туда можно получить функцией:

Теперь о самой процедуре сохранения, ее код приведен ниже.

Несколько пояснений по коду.

Не очень изящное, но простое как карандаш и реально работающее решение получить уникальное имя для файла в формате удобном для сортировки — «2011 11 17 20 31 49.jpg»
Здесь всего одна маленькая хитрость. Обратили внимание на time.month+1?
Дело в том, что Java считает месяцы с нуля, и ноябрь получается 10м, а не 11м, как все привыкли, месяцем. Непорядок.

Тут тоже все самоочевидно, споры могут возникнуть лишь о процентах сжатия. Мне кажется, что 85% оптимальный вариант, но у каждого может быть свое мнение и свои условия задачи.

Интересный финт, о котором многие забывают. Не все андроид-пользователи продвинуты настолько, чтобы отыскать сохраненные вами файлы, даже если вы им показали путь файловой системы. Но вот про приложение «Фотоальбом» знают точно все (это там, где только что снятые фоточки можно посмотреть). Добавьте вышеупомянутую строчку в ваш код, и картинка не только сохранится в нужную директорию, но еще и зарегистрируется в фотоальбоме, и пользователь всегда ее отыщет ее без всяких проблем.

Кстати, приведенная функция взята из реального работающего приложения Random Pictures, которое показывает случайные картинки из Интернета, а в платной версии программы — имеет возможность сохранения любой картинки к себе на флешку.

Бесплатная версия Random Picture Free на андроид маркете Random Pictures Free

Описанная функция сохранения файла работает только в платной версии. Ее цена — 45 рублей, но для хабражителей — конечно же выкладывается бесплатно. (Хорошая традиция, надо сказать!) Ссылка от автора в комментариях.

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How to save an image in Android Q using MediaStore?

Here is a link to the new Android Q Scoped Storage.

According to this Android Developers Best Practices Blog, storing shared media files (which is my case) should be done using the MediaStore API.

Digging into the docs and I cannot find a relevant function.

Here is my trial in Kotlin:

The result is that my image is saved here Android/data/com.mypackage.etc/files/Pictures/example.png as described in the Best Practices Blog as Storing app-internal files

How to save an image using the MediaStore API?

Answers in Java are equally acceptable.

Thanks in Advance!

EDIT

Thanks to PerracoLabs

That really helped!

But there are 3 more points.

Here is my code:

1- The image saved doesn’t get its correct name «Myimage.png»

I tried using «Myimage» and «Myimage.PNG» but neither worked.

The image always gets a name made up of numbers like:

Which bring us to the second problem:

2- The image is saved as jpg even though I compress the bitmap in the format of png .

Not a big issue. Just curious why.

3- The relativeLocation bit causes an exception on Devices less than Android Q. After surrounding with the «Android Version Check» if statement, the images are saved directly in the root of the Pictures folder.

Another Thank you.

EDIT 2

Here are the logs

I noticed the title to be matching the name so I tried adding:

It still didn’t work and here are the new logs:

And I can’t change date_added to a name.

And MediaStore.MediaColumns.DATA is deprecated.

Thanks in Advance!

4 Answers 4

Try the next method. Android Q (and above) already takes care of creating the folders if they don’t exist. The example is hard-coded to output into the DCIM folder. If you need a sub-folder then append the sub-folder name as next:

Consider that the compress format should be related to the mime-type parameter. For example, with a JPEG compress format the mime-type would be «image/jpeg», and so on. Probably you may also want to pass the compress quality as a parameter, in this example is hardcoded to 95.

Java:

Kotlin:

Kotlin variant, with a more functional style:

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android — save image into gallery

i have an app with a gallery of images and i want that the user can save it into his own gallery. I’ve created an option menu with a single voice «save» to allow that but the problem is. how can i save the image into the gallery?

this is my code:

i’m not sure of this part of code:

is it correct to save into the gallery? unfortunately the code doesn’t work 🙁

12 Answers 12

The former code will add the image at the end of the gallery. If you want to modify the date so it appears at the beginning or any other metadata, see the code below (Cortesy of S-K, samkirton):

Actually, you can save you picture at any place. If you want to save in a public space, so any other application can access, use this code:

The picture doesn’t go to the album. To do this, you need to call a scan:

I’ve tried a lot of things to let this work on Marshmallow and Lollipop. Finally i ended up moving the saved picture to the DCIM folder (new Google Photo app scan images only if they are inside this folder apparently)

And then the standard code for scanning files which you can find in the Google Developers site too.

Please remember that this folder could not be present in every device in the world and that starting from Marshmallow (API 23), you need to request the permission to WRITE_EXTERNAL_STORAGE to the user.

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How to download and save an image in Android

How do you download and save an image from a given url in Android?

11 Answers 11

Edit as of 30.12.2015 — The Ultimate Guide to image downloading

last major update: Mar 31 2016

TL;DR a.k.a. stop talking, just give me the code!!

Skip to the bottom of this post, copy the BasicImageDownloader (javadoc version here) into your project, implement the OnImageLoaderListener interface and you’re done.

Note: though the BasicImageDownloader handles possible errors and will prevent your app from crashing in case anything goes wrong, it will not perform any post-processing (e.g. downsizing) on the downloaded Bitmaps .

Since this post has received quite a lot of attention, I have decided to completely rework it to prevent the folks from using deprecated technologies, bad programming practices or just doing silly things — like looking for «hacks» to run network on the main thread or accept all SSL certs.

I’ve created a demo project named «Image Downloader» that demonstrates how to download (and save) an image using my own downloader implementation, the Android’s built-in DownloadManager as well as some popular open-source libraries. You can view the complete source code or download the project on GitHub.

Note: I have not adjusted the permission management for SDK 23+ (Marshmallow) yet, thus the project is targeting SDK 22 (Lollipop).

In my conclusion at the end of this post I will share my humble opinion about the proper use-case for each particular way of image downloading I’ve mentioned.

Let’s start with an own implementation (you can find the code at the end of the post). First of all, this is a BasicImageDownloader and that’s it. All it does is connecting to the given url, reading the data and trying to decode it as a Bitmap , triggering the OnImageLoaderListener interface callbacks when appropriate. The advantage of this approach — it is simple and you have a clear overview of what’s going on. A good way to go if all you need is downloading/displaying and saving some images, whilst you don’t care about maintaining a memory/disk cache.

Note: in case of large images, you might need to scale them down.

Android DownloadManager is a way to let the system handle the download for you. It’s actually capable of downloading any kind of files, not just images. You may let your download happen silently and invisible to the user, or you can enable the user to see the download in the notification area. You can also register a BroadcastReceiver to get notified after you download is complete. The setup is pretty much straightforward, refer to the linked project for sample code.

Using the DownloadManager is generally not a good idea if you also want to display the image, since you’d need to read and decode the saved file instead of just setting the downloaded Bitmap into an ImageView . The DownloadManager also does not provide any API for you app to track the download progress.

Now the introduction of the great stuff — the libraries. They can do much more than just downloading and displaying images, including: creating and managing the memory/disk cache, resizing images, transforming them and more.

I will start with Volley, a powerful library created by Google and covered by the official documentation. While being a general-purpose networking library not specializing on images, Volley features quite a powerful API for managing images.

You will need to implement a Singleton class for managing Volley requests and you are good to go.

You might want to replace your ImageView with Volley’s NetworkImageView , so the download basically becomes a one-liner:

If you need more control, this is what it looks like to create an ImageRequest with Volley:

It is worth mentioning that Volley features an excellent error handling mechanism by providing the VolleyError class that helps you to determine the exact cause of an error. If your app does a lot of networking and managing images isn’t its main purpose, then Volley it a perfect fit for you.

Square’s Picasso is a well-known library which will do all of the image loading stuff for you. Just displaying an image using Picasso is as simple as:

By default, Picasso manages the disk/memory cache so you don’t need to worry about that. For more control you can implement the Target interface and use it to load your image into — this will provide callbacks similar to the Volley example. Check the demo project for examples.

Picasso also lets you apply transformations to the downloaded image and there are even other libraries around that extend those API. Also works very well in a RecyclerView / ListView / GridView .

Universal Image Loader is an another very popular library serving the purpose of image management. It uses its own ImageLoader that (once initialized) has a global instance which can be used to download images in a single line of code:

If you want to track the download progress or access the downloaded Bitmap :

The opts argument in this example is a DisplayImageOptions object. Refer to the demo project to learn more.

Similar to Volley, UIL provides the FailReason class that enables you to check what went wrong on download failure. By default, UIL maintains a memory/disk cache if you don’t explicitly tell it not to do so.

Note: the author has mentioned that he is no longer maintaining the project as of Nov 27th, 2015. But since there are many contributors, we can hope that the Universal Image Loader will live on.

Facebook’s Fresco is the newest and (IMO) the most advanced library that takes image management to a new level: from keeping Bitmaps off the java heap (prior to Lollipop) to supporting animated formats and progressive JPEG streaming.

To learn more about ideas and techniques behind Fresco, refer to this post.

The basic usage is quite simple. Note that you’ll need to call Fresco.initialize(Context); only once, preferable in the Application class. Initializing Fresco more than once may lead to unpredictable behavior and OOM errors.

Fresco uses Drawee s to display images, you can think of them as of ImageView s:

As you can see, a lot of stuff (including transformation options) gets already defined in XML, so all you need to do to display an image is a one-liner:

Fresco provides an extended customization API, which, under circumstances, can be quite complex and requires the user to read the docs carefully (yes, sometimes you need to RTFM).

I have included examples for progressive JPEG’s and animated images into the sample project.

Conclusion — «I have learned about the great stuff, what should I use now?»

Note that the following text reflects my personal opinion and should not be taken as a postulate.

• If you only need to download/save/display some images, don’t plan to use them in a Recycler-/Grid-/ListView and don’t need a whole bunch of images to be display-ready, the BasicImageDownloader should fit your needs.
• If your app saves images (or other files) as a result of a user or an automated action and you don’t need the images to be displayed often, use the Android DownloadManager.
• In case your app does a lot of networking, transmits/receives JSON data, works with images, but those are not the main purpose of the app, go with Volley.
• Your app is image/media-focused, you’d like to apply some transformations to images and don’t want to bother with complex API: use Picasso (Note: does not provide any API to track the intermediate download status) or Universal Image Loader
• If your app is all about images, you need advanced features like displaying animated formats and you are ready to read the docs, go with Fresco.

In case you missed that, the Github link for the demo project.

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