问题
I have a android application, that uses many images. and application is to be used on different resolutions. I am using only one set of images and images are saved in "drawable-mdpi". So "The images gets blur when I run it on a high resolution". So probably the solution of this is to save different images of different resolution in drawable-hdpi,ldpi etc.
Is doing this is enough or do I have to change the images by code? or phone automatically adjust the perfact image into the drawables.
can anybody provide a example??
回答1:
If you put the images in the ldpi,mdpi,hdpi or xhdpi folders Android chooses the images according to the current device dpi.
If you only add mdpi ressources and load them on a hdpi device Android will enlarge the images with a factor of 1.5 if you open them on a ldpi device they will be shrunk with a factor of 0.75.
The scaling is applied so that the images have (almost) the same physical size all displays with any dpi.
You should add different images for each dpi if those images will be blurry (or loose details when shrinked) after this autoscaling. If you have simple images that look well after scaling you only need to add one image to any dpi folder.
EDIT: On Android there is no default way for automatically selecting images depending on the screen resolution. As the docs says:
When adding support for multiple screens, applications do not work directly with resolution; applications should be concerned only with screen size and density, as specified by the generalized size and density groups.
(see Supporting multiple screens).
回答2:
This is enough. This is the reason for having different folders in the drawable directory, but note that Android 1.5 supports only 1 folder called drawable with no subdirectories (but there are no phones on 1.5 with resolution higher than mdpi)
回答3:
One of the best ways of making sure your images are always properly scaled is to use 9 Patch drawables. Android will scale these according to the screen size automatically. They are best used for things that usually change size (Buttons, EditTexts, Spinners, etc), but can be applied properly in the right setting.
One advantage using 9 Patch images gives us is space-saving; having three different versions of images built into our applications can get quite large after awhile, but with 9 Patches you only need one copy.
See here for more details:
http://developer.android.com/guide/developing/tools/draw9patch.html
来源：https://stackoverflow.com/questions/8984848/how-android-drawable-automatically-change