问题
This is a scenario. There are folders:
- drawable
- drawable-ldpi
- drawable-mdpi
- drawable-hdpi
- draawble-xhdpi
An image (usually background, but not bound to such images only) is located in /res/drawable only.
I test the app on Galaxy S3 and the background is displayed properly. I test on HTC One X and background image is not being displayed.
If I copy the image from /res/drawable to /res/drawable-xhdpi, the One X will display image.
Thinking logically, this should not be happening, right?! If there is no image in drawable-xhdpi, then Android should look it into other folders until it reaches the default one /res/drawable and it should pull it from there.
Why is this not happening on some mobiles?
PS. I noticed the same issue with some tablets, but I cannot remember now which ones.
PPS. I mentioned background image here, but the issue is not bound to it. It also happens with other images. I am aware that xhdpi mobiles have issues with large images and I would not like you to think that the issue was with too large background image. It also happens with other images of "normal" size.
回答1:
why do you want to put an image file into the drawable folder ?
according to tips i've read over the internet , you should not put images files in the drawable folder .
in the drawable folder you put only xml type drawables.
if you want to put an image file , put it in any of the following folders (or add an additional qualifier for them , or use other qualifiers ) :
- drawable-nodpi (only for images that you don't know what should be their size)
- drawable-ldpi
- drawable-mdpi
- drawable-hdpi
- drawable-xhdpi
- drawable-tvdpi
images that are put into the drawable folder are treated as default , which is mdpi . so if you want to keep the file in the same screen density category , put it into the drawable-mdpi folder.
another reason for not putting an image into the drawable folder is that android will automatically convert the file to 16 bit image for some devices (like the samsung galaxy s) , which will make the image look awful on some cases.
here's a link that explains this issue .
回答2:
I made a project with a drawable that is only in the "res/drawable" folder, tested it on my One X, and confirmed the image is displayed:
https://github.com/lnanek/Misc/tree/master/TestOneXDrawableFolder
Layout:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<ImageView
android:src="@drawable/drawableonly"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
/>
</RelativeLayout>
Resources:
res
res/drawable
res/drawable/drawableonly.png
res/drawable-hdpi
res/drawable-hdpi/ic_launcher.png
res/drawable-ldpi
res/drawable-mdpi
res/drawable-mdpi/ic_launcher.png
res/drawable-xhdpi
res/drawable-xhdpi/ic_launcher.png
res/layout
res/layout/activity_main.xml
res/menu
res/menu/activity_main.xml
res/values
res/values/strings.xml
res/values/styles.xml
res/values-v11
res/values-v11/styles.xml
res/values-v14
res/values-v14/styles.xml
You can try to figure out what you are doing different that might be triggering some other behavior. Keep in mind that having a "drawable" folder and a "drawable-mdpi" folder is a little odd, because the drawable folder is mdpi density by default. It may be not be deterministic which of those two will get used. I know using a density specifier does automatically append a -v4 in modern build tools to fix problems with Android 1.5 not understanding these specifiers and handling them correctly, so drawable-mdpi-v4 might be considered to have more specifiers and match in precedence compare to drawable. Both folders have a mdpi density class anyway, however, so keep in mind your drawable from either folder will be scaled up automatically if used from there.
来源：https://stackoverflow.com/questions/14070124/why-dont-some-xhdpi-mobiles-display-image-located-in-res-drawable-only