I have been developing Android application since 3 to 4 months. I am naive, But pretty much exposed to all of the fundamentals regarding application development on android. However I found really painful while developing application with lots of images, By saying images I mean one of my application has around 10 to 13 images(Small enough to accommodate screen size). The problem is I have to make different copies of it by making,
HDPI - High resolution support
MDPI - Medium resolution support
LDPI - Low resolution support
I have come up with an idea,
IDEA : My idea is to actually have only MDPI images in drawable folder, When my
application will installed first time, I want my application to detect what type of
resolution is supported by device? After knowing which resolution is supported one of my
built in method will either use a MDPI version(images), if handset supports it or else
it will scale up or scale down my images and stores into internal storage for future
reference. When user uninstall my application I will remove these images from internal
storage.
Now this idea has raised a question,
Question :
Whether this idea is feasible? and Programatically possible?
If it is, Should I be really concerned about one time computational overhead?
Is there any mechanism(third party) which can ease my problem? (I hate photoshop and scaling up and down all those images)
Any expert help or guidance will be a big favour!
Thanks in advance!
Krio
I dont really understand why you would do this. The system already basically does this for you. You dont have to specify different images for different display densities, the system just gives you the opportunity to so you can make your app look its best. If you only supply a single image the system will scale it appropriately for you based on the density of the handset.
As for help with scaling the images yourself for packaging, you could look at image magick. This is a powerful scriptable image manipulation tool. You might need to spend a bit of time getting up to speed with it, but I am sure you could write a script that you could reuse for all of your images after that to convert high dpi images to lower dpi ones by scaling down.
Take a look to this article. It describes how android handle directory names for resources. Also take a look a look to this - how android choose the best match for directory name. If you want to use the same resource for all dpis just place it in the default drawable folder.
Related
I have three general questions regarding android's drawable folders.
Do i put different sized images in each of these folders, or will the images automatically scale themselves? As in, does android decrease the quality of the .bmp files automatically if placed in these folders?
When using the android design preview screen, will the appropriate image from the appropriate drawable folder be shown? If I have to make different sized images for each folder, I want to ensure that what i'm seeing in the design preview matches what is shown on other devices.
Lastly, do the drawable folders, if used, help to avoid the issue with failing to allocate memory for drawables on devices? I have had to scale my images down, and yet my college's phone still cannot allocate enough resources.
I couldn't find answers to these specific questions anywhere, so i'd really appreciate the help with these!
1) You don't need the different folders if you will put the same things in those folders. The designer/developer puts the resources that most adapt to that configuration.
2) You can select what kind of device you're previewing the design with (resolution and dpi), on the design tools. It will attempt to load the appropriate resource for that configuration.
3) Loading smaller images into memory may be helpful, as well as resizing them before displaying them (libraries like Picasso can do this out of the box), or you could be looking at a leak of some sort.
About your first question, you should create four different drawable folders in app>res in order to provide different devices (with different screen sizes and densities) more convenient images.
/drawable-ldpi For low density screens.
/drawable-mdpi For medium density screens.
/drawable-hdpi For high resolution screens.
/drawable-xhdpi For extra high resolution screens.
Android does not decrease the quality of .bmp files when they are allocated in those folders. You have to fill each folder with the correct sized images.
About second question, I am not sure whether the android design preview screen uses the correct images or not, but in a real app running on a phone, it will.
And third question: sorry, but not.
Good luck!
Ad 1 I always find it really helpful to load drawables to my project using Android Drawable Importer plugin. It will take care of loading appropriately-sized image into appropriate drawables folder.
Ad 3 If that works for you, maybe try loading images from server using tools like Glade or Picasso? That way you don't clutter your app with unnecessary resources, making it too heavy data-wise. Use a local drawable as placeholder only, in case there's no internet connection.
I'd also recommend using .png over .bmp format, .png are lossless and compressed, meaning your images can get significantly smaller while not losing quality.
You have to put images in different folders as per the image size. it will not generate automatically.
You can not select image for that screen. you can just select different screen sizes android studio will automatically use proper images for that.
For memory issue you can add this line in manifest :
android:hardwareAccelerated="true"
What is the best practice to store resources in libGDX library. I'm know that I can use AssetManager and also e.g. I can link the resources from android folder into iOS, but I dont know how it will behaviour on multiplatform devices. The resources are scale according to screen size/operating system, or I need to manually set diffrent size or resulution in each platform resource folder.I want to avoid any ovelaying or stretch behaviour.
There are many ways to go about this and there is no "best" solution. However if you do already build for android just use the android assets folder. This is the default and will be used for other builds (due to the default libgdx project configurations).
The resources only scale if you tell them too. You can choose to use a viewport (a fit/fill viewport will not stretch but can add black/background bars that do not have the default aspect ratio). But you can also choose to implement screen dependency yourself by using the aspect ratio and the scale.
For instance:
A 1080x1920 mobile phone vs a 1440x1920 tablet
If you use a fit viewport you will have unused space on the tablet. if you use a fillviewport you might lose stuff on the phone. But if you take the phone as a default aspect ratio and calculate the width offset for the tablet (1440-1080/2) you can use this value to choose to put actors/sprites on the same location as on the prone (by using this offset) or relative to the screen edge (by using the screen size). I personally use this to place the UI relative to the screen and the game itself the same as on the phone. You can even choose to use a different layout depending on the aspect ratio.
Do note that in this way you will also have to calculate a global scale and use this everywhere in your application. This can be tedious to implement but gives you much more control!
So if you have a simple game and you don't care about tablets or different screen sizes I suggest you start with a fit viewport.
p.s. Not sure what you mean by "multiplatform devices", but as I said, the default libGDX setup does the heavy lifting here, so I suggest you use it!
Okay so i have pictures on server. I would like to display them in my app as a part of a ListView row. I've already made that and now I have a question regarding the dimensions of the pictures. Since its a bad idea to save my image at 48dp sizes on server (36x36, 48x48, 72x72, 96x96 ..) and then download specific one for specific DPI device. Is it possible to only save a 96x96 and then set it to an ImageView. ImageView width and width = 48dp, and scaleType= fitCenter. Are there any better ways? please help me
You're right that you need only one image size on a remote server like 96px and then in Android app just fit it to your needs like 48px.
The easiest way to implement it would be using Picasso library.
Of course, there is a Glide, with many extra features, (so it might look at the beginnig a bit complicated for beginners), but for the most of uses Picasso is a enough solution.
You can also try a new library developed by Facebook, called Fresco,if you care also about memory using but I highly recommend you a Picasso.
Here you would find nice tutorial for this library:
https://futurestud.io/blog/picasso-image-resizing-scaling-and-fit
If you would find more information about these three libraries visit this site
Fragmented Podcast - 005 – Image libraries for Android
You can use Glide or Picasso for that. It's very easy to implement.
Here is a guide that explains a little as the two libraries and do what you ask.
I'm looking at making my own theme in CodenameOne but I cant find out quite what I need to do (I should point out I'm new to codename one)
From what I can see the key to what I need to do revolves around Multi-Images. I place an image there and the designer scales it multiple times so that I have all the images needed for the multitude of devices. Clearly, if it's scaling, the exact size of the image I put in Multi Image is a little irrelevant but what is the optimum size (presumably the close to the largest dimensions that will be used?). Can anyone give me an idea about the resolution of, say, a background image that I'm going to put into Multi Image and the correct (or best) aspect ratio?
Historically we recommended making retina iPhone sized images then importing them using the "Quick Add Multi Image" menu option and picking "Very High" as the target DPI.
This still works rather well but recently there has been an influx of higher DPI devices (iPhone 6+ and newer Android flagships) so we might update that guideline in the near future.
I work on a big project with codenameone(i can't attach my codes because it's really big). I get android app and it's works on android devices. But recently i get ios build for this project and it's not working on ios device(just showing a white page instead of map).
My project is a map-framework that render tiles and ... on graphics(i used graphics class for drawing, transforming, writing text and more).
I used input stream for working with file because of File not supported.
I need a solution to how debug and find my problem about ios build(why tiles doesn't showed).
In fact i don'n know anything about ios and objective-c.
Thanks in advance.
Most of the logging functionality that allows inspecting issues is for pro developers (you can try the trial) its discussed in this video (mostly focused on crashes): http://www.codenameone.com/how-do-i---use-crash-protection-get-device-logs.html
From your description I would guess you created a really large mutable image (larger than screen bounds) and are drawing onto that. This would be both slow on iOS (and on newer Android devices) and might actually produce that result if the image exceeds the maximum texture size of the device.
If that is not the case you would need to explain what you are doing more precisely.