i just released my app on android and have problems with customers with high density displays.
i added a debug thing to see what's going in, here is one sample output
Device: Nexus 10 Android version: 4.2.2
DisplayMetrics{density=2.0, width=2560, height=1504, scaledDensity=2.0, xdpi=298.275, ydpi=298.823}
MainView w=1900 h=1342
mDrumKitMode=BIG
KitView w=640 h=1266 x=1920.0 y=0.0
the main view is the music notation area on the left of the screen shot, its 1900 wide (MainView w=1900 h=1342) the drum kit is a bitmap that is 640w and 640 high. somehow, the display is scaling it to be full height of the parent, (KitView w=640 h=1266 x=1920.0 y=0.0). this doesn't happen on displays where density=1.0.
i have no way to test this since i can't get the emulator work on big displays for some reason and i don't have a high density tablet.
does anyone have an idea what could be going on? thanks
and here's another customer with a similar problem
Device: A700 Android version: 4.1.1
DisplayMetrics{density=1.5, width=1920, height=1128, scaledDensity=1.5, xdpi=224.73732, ydpi=224.11765}
MainView w=1260 h=1044
mDrumKitMode=BIG
KitView w=640 h=968 x=1280.0 y=0.0
i think its the scaledDensity=1.5 parameter, maybe i need to do something to disable automatic image scaling, i.e. set scaledDensity=1?
i should add that the entire application is based on exact pixel positions, both for the music notation display and the drum kit display which overlays images on top of the base drum kit image (you can see the drum pedals are in the wrong place on this image too). i don't want automatic scaling as i handle scaling inside the app for different display sizes and user preferences.
i should also add that all my drum kit images are in drawable-mdpi and all the other dpis are empty. this is because i scale images programmatically based on screen size and user preference BUT i think maybe the problem is a need to put some images in xhdpi? i guess i can do that but it will be a lot of work.
PS, i guess i found my answer here http://developer.android.com/guide/practices/screens_support.html
Provide different bitmap drawables for different screen densities
By default, Android scales your bitmap drawables (.png, .jpg, and .gif files) and Nine-Patch drawables (.9.png files) so that they render at the appropriate physical size on each device. For example, if your application provides bitmap drawables only for the baseline, medium screen density (mdpi), then the system scales them up when on a high-density screen, and scales them down when on a low-density screen. This scaling can cause artifacts in the bitmaps. To ensure your bitmaps look their best, you should include alternative versions at different resolutions for different screen densities.
i wonder if simply copying all the -mdpi images to -xhdpi will work?
If you intend for this app to be used across devices you have no choice but to put in images for all the various density folders that exist (xhdpi,xxhdpi, hdpi, mdpi). It's also worth considering that you may want to change the actual layouts you include, to offer different ones for different devices.
Consult the documentation for how to handle this.
http://developer.android.com/guide/practices/screens_support.html
If that creates an apk that's too heavy (I have no idea how many images you have) then you can go the other way and specify a no scaling drawable folder which will just use the images in their native density across devices. It's definitely wrong to use ONLY mdpi unless you intend to support only mdpi devices.
Related
I want to add a background image to one of the screens of an Android app. (This image is a photo so 9-patch will not work).
I want scale this image for various different resolutions.
Android organises images uses DPI (i.e. ldpi, mdpi, hdpi, xhdpi, xxhdpi, xxxhdpi). However this does not seem useful in this particular situation as I want to use an image that covers the ENTIRE screen. DPI does not tell me how big the entire screen is. For example, a xxxhdpi screen may have a lower resolution than a ldpi screen.
To illustrate this issue consider the following devices:
Samsung Galaxy Tab 10: mdpi, 800px x 1280px
Moto G: xhdpi, 720px x 1280px
As you can see the first device requires a larger resolution image, despite having a lower dpi.
Therefore my question is, how do I create an image that covers the screen for different screen sizes.
You can find several answer at stackoverflow like: Android: Background Image Size (in Pixel) which Support All Devices
Another reference including tablets can be found at: Is there a list of screen resolutions for all Android based phones and tablets?
The detailed description can be found at: https://developer.android.com/guide/practices/screens_support.html
One point you need to keep in mind is how the image will cover your layout, you need to fit using center crop as scale type.
Remember to leave some space from borders at least not including important information that could be cropped from the border based on the real device size.
Another way to add backgrounds for multiple size and densities is not trying to cover the entire scree just a mix. A gradient plus some image can give you enough flexibility many times.
Another solution is using a blurred image which do not interfere with the rest of the information shown. In this case because of the nature blurred of the image, it is not required to be detailed.
Hope it helps.
As far as I know it is possible to provide multiple resource paths for multiple dpis (mdpi, hdpi etc.). What if I want to support multiple screen sizes at the same dpi?
For example, if I have an application that draws an icon whose size is always a percentage of the screen size (e. g. 25 %) and I replace the screen by a larger one with the same dpi, then the icon has to be scaled up. This will make the icon blurry unless I provide a version with a higher resolution. Since Android only distinguishes by dpi and not by screen size, how can I do this?
If the icon is included in the APK, you may as well just put just one copy - the highest resolution you have. Large icons can be scaled down just fine, it's scaling small icons up that causes the blurriness. The reason for including different sizes is to save bandwidth when icons are downloaded, but since all the copies would already be on the device, in effect all you will be doing is making the APK bigger. First prize would be to include a vector image (infinitely scalable, small size).
You should also note that the blurriness is really only in comparison with the sharpness of the rest of the display. In reality the 2x scaled-up icons would look just as good as the same icons on a display with a density half as much.
If, however, you still want to select a certain copy of an image based on the dpi and screen size, there are ways you can detect this in Android. See this SO question, for example.
I making an app for tablets. and want to use a PNG file for some of the buttons. What size the button must be? Based on Android size it should be at least 48dp x 48dp and with converters 48dp is different in different sizes of android devices. This is a calculator: Link
ldpi # 48.00dp = 36.00px
mdpi # 48.00dp = 48.00px
hdpi # 48.00dp = 72.00px
xhdpi # 48.00dp = 96.00px
So Should I make 4 different files for my png files with top pixels ? for example a version with 36px x 36px for the ldpi folder? or just make the biggest size like xhdpi (96px)?
Thanks in advance.
You CAN just make one large button size and get away with it, but thats not best practice.. You should have different sized images for different resolutions.
From Android:
Although the system performs scaling and resizing to make your application work on different screens, you should make the effort to optimize your application for different screen sizes and densities. In doing so, you maximize the user experience for all devices and your users believe that your application was actually designed for their devices—rather than simply stretched to fit the screen on their devices.
More info on supporting different devices and best practices.
Android Practices
Ya. Better Use 9 patch Images as the background for the buttons. So it will expand/ behave according screen size . Check this Link .
I just use the highest resolution and let Android scale it down. Doing it this way makes the download (file) size much, much smaller than having a different image for each resolution. And the quality as it's scaled down is no worse than it would be if you scaled it down yourself in MS Paint.
I am kind of confused about managing graphic resources in Android.
Tried to read this doc but It only confuses me more. Can anyone give me some example of how should I handle the following case?
Lets assume that I have an image in my layout that will be scaled to fill screen width. What image sizes (in pixels) should I produce and what configuration qualifiers (drawable-{qualifier}) should I apply to those resources to cover all major dpi and screen sizes (both for tablet and handset)?
Thanks.
If you want to have an image, that is supposed to fill the screen it is best to use 9-patch images. This way your image can automatically scale to fit the device. Because even if an image has the correct density, the actual screen size can vary. For example a smartphone and a tablet can both be hdpi, but have completely different screen sizes (and actual pixel count).
So the easiest way to target most devices, when it comes to images that are supposed to fill up the full width of the screen is to have a 9-patch image and create ldpi, mdpi, hdpi and xhdpi versions of it. This way the image will automatically be choosen depending on the density and then stretched to fit the device.
The android sdk also provides a tool that helps with creating 9-patch images http://developer.android.com/tools/help/draw9patch.html
I have a game which displays a full screen image in the background. At the moment I have one image size (1280x800). This works well on large resolutions but on smaller screens the shrinking somewhat degrades the image. You can see jagged edges and it is noticeably worse than what you could achieve using photoshop software.
I have different image sizes, but I am unsure how to utilize them. I know there are different dpi folders, but you can have resolutions of 480x320 and 1280x768 with the same dpi so I don't think these can be of use here.
I believe you can have different layout files for different screen sizes, but the image is not drawn using xml (and in fact would not be possible for my game).
I can only think that I must create a different file name for each size. Then when choosing which image to use I could take the screen dimensions and select the correct one? I am struggling to see how I can make an image look good on both 240x320 and 1280x800 resolutions.
All of the resource qualifiers in the framework can be applied to drawables, not just the dpi designators. In other words, you could create folders like this to segment your images as well:
drawable-ldpi
drawable-xlarge
drawable-normal
drawable-sw480dp
drawable-sw720dp
Even examples like these work...
drawable-v10
drawable-land
And so on...
You can create as many or as few different qualified directories for your image assets as you think necessary to preserve the quality. The Supporting Multiple Screens article in the SDK docs helps describe most of the qualifiers that best fit scaling image assets.
HTH!