I know there are tons of questions on this topic, but I tried searching through tons of "android dpi" posts and read the online documentation but haven't found the exact question that I have.
If I want to create a button (or any image resource) that will take up the same space on the screen on all devices - how do I do that?
I understand that there are specific screen sizes and dpi's that Android looks at etc. but I don't quite understand how big a specific image should be to look right on any screen.
Say that I have the following setup for my drawable and layout folders (Application is only landscape):
res/drawable-ldpi/button.png (120 dpi)
res/drawable-mdpi/button.png (160 dpi)
res/drawable-hdpi/button.png (240 dpi)
res/layout-small/main.xml - button is set to 100dp
res/layout-normal/main.xml - button is set to 100dp
res/layout-large/main.xml - button is set to 100dp
Say I have a button that I want to be 100dp on any screen. Following the 3:4:6 scale ratio rule it seems that if I have a button resource that's 100px wide for the mdpi density I should make another button for the ldpi density that's 75px, and one for the hdpi density that's 150px. Is that correct? Do I create the 75px button at 120dpi, the 100px button at 160dpi and the 150px button at 240dpi and then just say android:layout_width="100dp" in all three layout files? Or do I make all three buttons 100px at the different dpi's?
Now what if I have that button 9 patched. Do I have to create the button three times at 120dpi, 160dpi and 240dpi all of which are 100px in size? Or do I just create one 9 patched button at 100px and 160dpi and place it in the mdpi drawable folder?
The online documentation is a bit confusing for me so I'm looking for a simplified answer.
This is for Android versions 1.6+ (Not the new stuff for 3.2 etc)
Thanks for your help ... I just want a button to take up the same space on a 3.7" screen as a 7" screen and not be blurry!
Did you sort this? Afaik, and from my experience, don't change the dpi when creating the images in say, Photoshop. I always left mine at standard which is 72 I think. Regardless, I don't think it matters if you set it to a million.
The px values you mentioned are correct for l m and h.
I would leave the mdpi qualifier off the folder name though; I'm unsure of the protocol if on an xhdpi device there is no drawable folder with no xhdpi qualifier and no folder without qualifiers.
Workflow:
Create your images at 75, 100 and 150.
Put 75 in ldpi folder, 100 in drawables folder with no qualifier, and 150 in hdpi.
Leave your layouts as they are now, with the 100dp. They should scale correctly. That said, I don't think you need to specify the image size if you're using the full resolution.
Comments to address inaccuracies in my answer are always welcome, even years down the line.
Related
I made my first Android App. I read a lot about the images and made separate sizes for mdpi hdpi xhdpi and xxhpi.
Although i noticed i'm still having some issues on smaller screens 3.7" and 4.0" inches. What i noticed is that i'm using fixed values for things like buttons TextViews and Text sizes.
I came across and read about the dimens files but i'm still a little confused as to how should the folder structure should of the values.
To be more specific
drawable
drawable-hdpi
drawable-mdpi
drawable-xhdpi
drawable-xxhdpi
How is the values folder structure should be ?
I've read somewhere that it should look like values-sw600dp.
But what does the 600dp represents ?
600dpi and up ??
Can i use custom values there or are there some fixed ones??
Thank you
after version 3.2 sw600dp is used for multi-layout panes for devices whose dp is greater than 600, where dp is :
px = dp * (dpi / 160)
This is irrelevant to your requirement (unless you want to make apps compatible for tablets).
Just make sure you put proportional image sizes in xhdpi,xxhdpi,mdpi and ldpi folders and use wrap_content for images. You can also use constant sizes, just make sure that you use dp for buttons and sp for text size.
I'm trying to support mdpi, hdpi and xhdpi on my current App. The problem is that I'm fetching images from the web (profile pics). I'm using an imageview with height = 200dp the thing is that even tho I have read tons of tutorials and documentation about dp and dpi, I still don't get them.
So my problem is that on an hdpi phone (atrix 2) the image takes about 1/3 of the screen, which is perfect for me. but on mdpi (galaxy ace) it takes almost 2/3.
What's the best way to set a height for an imageview (from the web, not resources) to support mdpi and hdpi.
thanks
<ImageView
android:id="#+id/expositor_image"
android:layout_width="match_parent"
android:layout_height="200dp"
android:layout_below="#+id/expositor_info_header"
android:layout_centerHorizontal="true"
android:layout_marginTop="-27dp"
android:contentDescription="#string/misc_placeholder"
android:scaleType="centerCrop" />
basically my problem is that the 200dp takes different % of screen on mdpi and hdpi
For starters, you are going to want to set a scaleType (try "center_inside") in your xml definition of the ImageView.
If you provide some code (in particular your layout xml file) I might be able to be of more assistance.
Update
Now, this may not fully be your problem, but it is a piece of it. DP (or DPI, they are the same thing) adjust for the screen density (pixels per inch), not the screen size. That means that an image of 200dp x 200dp will be approximately the same size in inches on both screens, not the same percentage of the screen.
Specs:
Atrix 960 × 540 (https://en.wikipedia.org/wiki/Motorola_Atrix_2#Features)
Galaxy Ace 480 x 320 (https://en.wikipedia.org/wiki/Samsung_Galaxy_Ace)
Since the Atrix is hdpi, and hdpi is a 1.5 multiplier, 200dp will take up 300px in real pixels, or approximately 1/3 (300/960) of the screen as you point out.
On the mdpi Ace, the 200dp translates evenly to 200px, which should be closer to 1/2 the screen. However, with the addition of the actionbar taking up screen real estate, it may seem like more.
The best way to deal with very small screens like the ace... well, my normal solution is to not support them very well, at least not on my first pass, as they are pretty rare. But if you want to, the best way is to provide alternate layouts.
For Example:
Create a folder named layout-large (or similar, see: http://developer.android.com/guide/topics/resources/providing-resources.html#Compatibility).
Make a copy of your existing xml file in that folder. (name must be exactly the same)
Modify the file in layout/ so that it works better on smaller screens.
Essentially, if the device has a "large" screen or above (where large is basically the standard these days), it will use the layout in the layout-large/ folder.
Otherwise, it will use the default layout in the layout/ folder.
If you think this explanation is not what is happening, please provide screen shots to verify that the layout is in fact not behaving like it should.
I know it is a common problem but I didn't find the solution. When designing buttons for android you have to design for specific DPI but with MDPI there is a problem;
The smallest mdpi is 320x480, so i created the button to fit the smallest screen, but if u see at the 5,4 device which is mdpi to it is 480x854. The buttons looks to small for that screensize but i can't make them bigger because they don't fit on the 320x480 screen anymore?
Is there a an other way to make the buttons fit the screen? For tablet it also uses the mdpi images so it looks very tiny..
After searching a bit longer I've found the answer:
U have to add
drawable-large-mdpi
as folder to the res, and place the buttons there
I'm trying to develop for an android tab with the resolution of 1280x720. But when I place an image, say 1000x500, into the xml view it appears almost two times smaller. When I change its height and width from wrap_content to 1000px and 500px, it looks ok in xml, but when I launch it in the emulator, it gets very blurry, as if it would be at first scaled down and then expanded again.
Any ideas?
Thanks!
Put the drawables for tablet in the drawable-xlarge folder and the problem may dissapear.
Maybe your problems is that the most tablets have xlarge screens and mdpi screen density and you put the drawables in the hdpi folder.
For more info see this page.
Try using "dp" instead of pixels. Also place the drawable in the density specific folder. between ldpi and hdpi the size in pixels need to be twice for them to show up as of same size on the device. For example a launcher icon on ldpi device is 36 x 36px while on hdpi it is 72 x 72 px
Use same ratio to create your image in higher resolution with larger size.
For my app I need several small icons. I put them at a size of 15dp * 15dp in the layout xml file. The problem is that they do not look good on the device. If I look at the standard android Icons, e.g. for refresh, they look very sharp.
What I did was, I created a 15*15 pixel image with Gimp and tried to use it. I guess that is not a good approach since 15dp != 15 px, right? What is the usual workflow for creating nice, good looking icons, even if they need to be small?
Density-independent pixels (i.e. dip or dp in XML) are designed to provide a more consistent visual appearance across devices by scaling the UI to look roughly the same size on each device. This is not the exact same as physical size scaling, but rather the pixel density (dpi) of the screen. There are basically four buckets any device can fall into (ldpi, mdpi, hdpi, xhdpi). The dp unit is modeled after mdpi, and all other buckets are scale factors from there. In other words, 15dp does equal 15px on an mdpi device, but not on others.
What you need to do for optimum performance is to create your icon in four sizes, and place them in corresponding drawable/ directories. For instance, with your 15dp icon you should have:
A 12x12px image in a res/drawable-ldpi folder (LDPI is 75% of MDPI)
A 15x15px image in a res/drawable-mdpi folder (MDPI is the base)
A 23x23px image in a res/drawable-hdpi folder (HDPI is 150% of MDPI)
A 30x30px image in a res/drawable-xhdpi folder (XHDPI is 200% of MDPI)
The application will grab the proper asset to match the resolution of the device you are running on. If you do not create an asset for each level, the application will take the closest match and scale it up or down (You are probably using an HDPI device to test and your 15px image was getting scaled up to 23px, causing pixelation).
HTH!
According to this page, dp is a unit of scale-independent pixels: 160dp always makes 1 inch on your screen. This should answer your question whether pixel is dp or not: It is only the case with a screen supporting 160dpi. This is a lot more than e.g. the usual PC screens these days (96 dpi).