问题
I have an image with dimensions 250*70 pixels under drawable folder (I'm just starting out in Android development, so i created drawable folder in res) and I have the same image with higher dimensions in drawable-large folder; but the image is not looking as I expected.
Can anyone explain the reason behind/purpose of 3 drawable folders?
Where should I store my image so that it displays properly in both modes (landscape & portrait) and in all the mobiles (including tablets)?
I want my image to scale dynamically to the size of the device screen.
Can anyone share your views or links to search ?
回答1:
By default Android maintain three folders for the images with different resolution reason behind it is the use or the resolution of the Android Device on which the application gonna execute.
hdpi image folder maintain images for the Android Broad Screen set or Android Phones with the Higher resolution.
ldpi for Lower images quality which supports by the earlier sets of the android
mdpi for medium images support xhdi images folder for devices with maximum resolution.
Android OS select the image it self by checking the compatible device and its resolution.
Hope it helps. Accept if you get your explanation.
回答2:
The folder names need to be :
- /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
/drawable should be reserved for assets that you either (1) don't care about which device or for (2) xml drawable assets
Then on top of that you can provide different resources based on configuration by using config qualifiers, you can read all about it here http://developer.android.com/guide/topics/resources/providing-resources.html
for instance, you can have high resolution assets for landscape with a folder
- /drawable-land-hdpi
Hope that helps
回答3:
drawable-ldpi
drawable-mdpi
drawable-hdpi
drawable-xhdpi
drawable-tvdpi
drawable-nodpi
drawable-xxhdpi
drawable-xxxhdpi
We can also use "drawable-xxhdpi"
xxhdpi (480dpi, Android 4.1 or later)
Refer "Android Tabular Column" in the following link
http://en.wikipedia.org/wiki/Smartphone
Please refer "Table 1" in the following link (xxxhdpi)
http://developer.android.com/guide/practices/screens_support.html#xxxhdpi-note
Note: the drawable-xxxhdpi qualifier is necessary only to provide a launcher icon that can appear larger than usual on an xxhdpi device. You do not need to provide xxxhdpi assets for all your app's images.
Note will be in the following link http://developer.android.com/design/style/iconography.html#xxxhdpi-launcher
回答4:
You should use drawable-hdpi folder instead of drawable-large.
Also Supporting Multiple Screens page may be helpful for you
回答5:
actually there are 4 screen resolution standards - check this link for more information http://developer.android.com/guide/practices/screens_support.html , the table below. When you install your app on device, the device return one of these standards and pick the resources from the corresponding folder - ldpi, mdpi, hdpi and xhdpi
回答6:
1) The reason behind the different drawable folders - to enhance user experience when using our app, by accomodating each device's screen density.
2) "Where should I store ..." - ideally, you store an image with the appropriate size for each screen density that exist. If you are a beginner, just use one folder and don't worry about it now.
4) Image scaling Here's a cool guide that helps you with image scaling inside the app: https://thoughtbot.com/blog/android-imageview-scaletype-a-visual-guide
3) Links: https://material.io/tools/devices/ - list of all devices and densities
来源：https://stackoverflow.com/questions/10517389/android-understanding-drawable-folder