I made some 9 patch images to use as a button, but the device doesn't recognize them.
9 patch image:
How eclipse shows it:
How my device shows it:
As you can see, the english button has two black pixels at the top and slovenian only has one. I did this to try if two pixels would work, but it still didn't.
I'm pretty sure I did everything right. Names are in the right format (name.9.png)
Your problem is that your right border is not continuous. The right border defines the padding, and must be a continuous line (or a single pixel). You seem to simply have the logic inverted, but it should be like this instead:
9-patch images have to be pre-compiled, when the one pixel border is removed and encoded to a PNG chunk. Your image is not being pre-compiled. That's why the black pixels still appear, and the image is not being correctly stretched.
Make sure your images are in one of the drawable folders, and their name ends with .9.png. If everything is right, try to clean and build your project.
I am trying to use the card_background 9-patch that is extracted from the play store apk and I am having trouble getting the 9-Patch to place itself correctly. Here is an image of my emulator running this problem. I am trying to make the typical card view that is used somewhat commonly now but this is just one of the problems I cannot work out how to fix.
My 9-Patch card_background:
I am also pretty sure the 9-Patch is setup incorrectly as according to the 9-Patch tool in /sdk/tools the entire two areas that I am using are both bad patches but I don't know what that means so I hope one of you can help to fix this.
I modified your image, I think this works:
Your 9-patch image stretches all the white/border correctly, but it has nothing but transparency at the bottom. If you want a gray shadowy area beneath it, you need to draw it there, below the white. Just make sure you don't extend the black stretch-bar down to it, or it will stretch as well.
Go into the sdk's nine-patch editor tool after you extract the png's from the apk and put them in their respective drawable folders. The tool can either be the one inside the /tools or, even better, the direct editor in Android Studio.
Modify the stretch regions for each image to your liking until it looks like an actual card. I had the same problem, until I went back and redid the stretch regions. For some reason, the png extracted from the apk didn't save the stretch regions when extracted.
You should have a shadow automatically appear from the given images, you DO NOT need to draw it yourself. Just make sure you don't include the corners and the shadow in the stretch region. And give a little bit of slack too.
I recently heard about 9-patch images. I know its 9 tiled and is stretchable. I'd like to know more about it.
How can I create a 9-patch image?
Is there any tool? Can I create it from AndroidSDK or code?
Main Advantages of 9-patch over regular png?
(is it stretchable dynamically/ automatically according to screen?)
The SDK and Android Studio both ship with the "Draw 9-patch" tool ("draw9patch" in the SDK tools folder) which is a simple editor. Here is a nicer one which is also open source. It has a simple but clever default image.
The official documentation has improved over the years. In summary, nine patch images' most important advantage is that they can specify (non-contiguous) areas to scale:
A NinePatch graphic is a standard PNG image that includes an extra
1-pixel border. It must be saved with the 9.png extension in the
res/drawable/ directory of your project.
Use the border to define the stretchable and static areas of the
image. You indicate a stretchable section by drawing one (or more)
1-pixel wide black line(s) in the left and top part of the border (the
other border pixels should be fully transparent or white). You can
have as many stretchable sections as you want. The relative size of
the stretchable sections stays the same, so the largest section always
remains the largest.
You can also define an optional drawable section of the image
(effectively, the padding lines) by drawing a line on the right and a
line on the bottom. If a View object sets the NinePatch graphic as its
background and then specifies the view's text, it stretches itself so
that all the text occupies only the area designated by the right and
bottom lines (if included). If the padding lines aren't included,
Android uses the left and top lines to define this drawable area.
But the docs lack good examples. This tutorial has some great examples at the end that answer the second part of your question, explaining how the scaling works - not just for buttons - but also frames, and it has a complete example project that you can download and play with.
Most of the examples talk about creating a 9-patch image, but implementation details are usually left at a high level.
Nick's post above - with the good 9-patch tutorial that provides a working project download file , saved the day.
Here are the main implementation details that worked for me (once you have a 9-patch image ready to go):
Reference the drawable with the name but don't include .9.png (auto-complete in eclipse will take care of this)
Make sure you only have 1 image under the main /drawable folder (not a version for each dpi folder)
The image must be specified using :background, not :src (this got me stuck for a while)
android:background="#drawable/splash_logo"
Make sure the image and layout that contains it are using:
android:layout_width="fill_parent"
android:layout_height="fill_parent"
How can I create a 9-patch image? Is there any tool? Can I create it from AndroidSDK or code?
When you search a major search engine for android 9-patch tool, the very first hit is for the Android developer documentation page on the draw9patch tool.
Main Advantages of 9-patch over regular png? (is it stretchable dynamically/ automatically according to screen?)
The Android developer documentation contains other pages that describe nine-patch PNG files. This documentation includes passages like:
A NinePatchDrawable graphic is a stretchable bitmap image, which Android will automatically resize to accommodate the contents of the View in which you have placed it as the background. An example use of a NinePatch is the backgrounds used by standard Android buttons — buttons must stretch to accommodate strings of various lengths.
With 9-patch image you can choose which part of your image may be stretched.
It must be png image and name must end with .9.png (something.9.png)
http://developer.android.com/tools/help/draw9patch.html
Simple tool for all densities:
http://android-ui-utils.googlecode.com/hg/asset-studio/dist/nine-patches.html
1.What are NinePatch images?
NinePatch images are PNG images that mark the parts of an image that can be stretched. They have an extension like image_name.9.png.
2.Where they are stored in android project ?
res/drawable/image_name.9.png
3.How to create NinePatch image for your anndroid app ?
Android SDK includes a WYSIWIG draw9patch.jar tool inside your Android SDK /tools folder.
Main Advantages of 9-patch over regular png
Actually 9 Patch images are stretchable, repeatable images reduced to their smallest size.the image won't stretch and loose proportions in different screen sizes. One more and biggest advantage is memory.
Same small size memory can be reused for different screen size devices. Well-designed 9-patch images are less error-prone and have high re-usability .
https://developer.android.com/studio/write/draw9patch.html
This is good tool:
Click here.
9 Patch images are stretchable, repeatable images reduced to their smallest size. The simplest example would be if you were to take a rounded div and slice it up into 9 squares like you would a tic-tac-toe board. The four corners wouldn't change sizes at all but would be static while the other 5 pieces would be stretched or repeated to allow the whole image to scale appropriately.
With that explanation and the advent of CSS3 you might think that there is no reason to use 9 patch images but the name '9 patch' is a misnomer. The images can be sliced up into even smaller pieces.
9 Patch images contain an index of which piece is what by adding a 1px border to the image. The colors in the border determine if a piece is static (doesn't scale), it stretches, or it repeats.
Google Slideshow: https://docs.google.com/present/view?id=dc7ghz8w_34f8338rcg
See also the Android developer info about 9-patch images: http://developer.android.com/guide/topics/graphics/2d-graphics.html#nine-patch
Step 1, Since you are not familiar yet, prepare a xxxhdpi png big image to play around first.
Step 2, That image desired expandable field must shorter (by removing redundant/repeated color part) as possible since 9-patch no such thing "reduce", but "expand" the image.
I personally use the ImageMagick command line tool to convert it, e.g.:
convert -trim 'my_image.png' png32:my_image_trim.png #trim extra transparent surrounded image
rm lala*; convert my_image_trim.png -crop 310 +repage +adjoin png32:lala%02d.png #cut redundant/repeat center part
convert +append lala02.png lala05.png png32:out_right.png #append left/right images side by side
convert -resize 144x144\! out_right.png png32:my_image.png #resize to the desired dpi
There is one pitfall when convert: I must prefix with png32, or else will get black 9-patch image, see this thread.
Step 3, Copy image to Android Studio drawable, then right-click and choose menu item "Create 9-Patch file...". A .9.png new image will be generated with the same image name. Now can just delete the original image. Careful when playing around with refactor to rename for backup since it will rename the XML image id too, and make you wonder why the 9-patch image not working since XML still referring non-9-patch image.
Step 4, Left and top 2 black lines form an expandable rectangular area, while right and bottom 2 black lines form a text rectangular area.
Your image size will grow on your declared expandable area as text growing. While the text area means text only allow in that area.
You don't have to draw the black dot/lines from scratch for simple usage, 4 black lines already existed behind the top, left, bottom, right on that image if your 9-Patch image generated by Android Studio. "Zoom in" to bigger if you can't see to drag that lines.
The original position of 2 black lines, vertical and horizontal, both declare an expandable area:
The original position of left vertical line is between upper left to bottom left
The original position of top horizontal line is between upper left to top right.
The original position of 2 black lines, vertical and horizontal, both declare a text area:
The original position of right vertical line is between upper right
to bottom right.
The original position of bottom horizontal line is
between bottom left to bottom right.
Above is the original position of black lines before you start to drag to narrow down the length, to adjust the start position and end position of that lines.
Both expandable and text areas can be different depends on your needs. But normally expandable area should equal OR less than text area, a classic example will be chat bubble image:
The image above has equal top and bottom black lines width but right black line is higher than left line, which also means that text consistently stay up to half of bottom curve in either minimum size or expanded size. And it only expand in body of text area.
Now you will know the two benefits of 9-Patch: the bottom and right line together form a text area which perfectly ensures text never overflow to outside of image curve ! And also defined which portion of text area responsible to expand the image as text growing, while keep the curve without scaling.
Hover the line will able to see the x,y positions in pixels, it help to measures both lines are equal or less in position.
You should remember the position of line when dragging, since left line can drag to right side, and the right line can drag to left side, and you may get lost of which line is expandable line and which line is text line.
There are 2 important checkboxes you should tick, i.e. "Show patches" and "Show bad patches" checkboxes.
In "Show bad patches" checkbox, if you drawing the expandable area but covering the curved line of your image instead of a straight line, then it will mark that area as red to warn you. You can narrow your line to dismiss that red warning, or just ignore it. Keep in mind that, the red warning may misleading which may actually be caused by the opposite line, in that case, you need to narrow the opposite line to dismiss that red warning.
Step 5, In xml, you can refer to that image as TextView background like below, use wrap_content to make it expandable:
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#drawable/your_9_patch_image_name_excluded_.9"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
<2nd TextView />
</LinearLayout>
When first time playing around with it, ensures no padding on textview or fancy parent layout, or else you may wonder why not working as expected.
Button background example:
<Button
android:id="#+id/btn2"
android:layout_width="wrap_content"
android:layout_height="40dp"
android:background="#drawable/your_9_patch_image_name_excluded_.9"
android:layout_gravity="center"
/>
I've made this 9-patch png and added it to the res/drawable folder:
It works nice in the example eclipse shows:
But on the emulator it looks messed up:
Why is this happening and how can I fix this?
EDIT: The border on which I've placed the black dots is white, not transparent. Not sure if that's got anything to do with it...
This probably happens because you have a small mistake with the black pixels you have set.
Try to re-cut the edges of the picture and to add the black pixels all over again.
I had this problem too once and this helped me.
if the border is white then this is your problem it has to be pure black or nothing at all.
UPDATE: Try this image:
It seems you are not saved your image with .9.png
In order to make it work do like this
save your image in the following format in your drawable folder
yourimage.9.png (not png format of your image)
Check this reference draw 9 patch
The Android SDK contains a 9-patch editing tool (draw9patch.bat) that can help you to produce and/or validate 9-patch images. Without it, it is very easy to make a mistake in defining your border.
The one-pixel border should be transparent except for the black pixels that define the various parts of the image to be treated differently during scaling.
I need express help with 9 patch. I run draw9patch and change and save as name.9.png and save at res/drawable ( later tried in res/drawable-hdpi but didn't help) but problem is when I show on devic/emilator it doesn't strech and that black pixels at border are still visible ( I thought it is visible only inside 9patch for creating intersection ). Can somebody told me what is wrong ? I saved as name.9.png but it seems like it not recognize like 9.patch
Ensure transparency is not set in the outer pixel border that sets the patches. The Draw9Patch tool accepts it so it looks correct but it never actually works in my experience.
Ensure your 9patch image is named like this: imageName.9.png