Dear Fellow Developers,
I've ran into the problem shown in the attached picture. We have been trying to tweak the dropdown menu's 9patch image provided by a graphics designer, but could not get it to work. The black stretch markers are not being hidden, and Android does not stretch it the way we would expect.
The device is a Nexus 7. We have tried several various image sizes, but none seemed to work. I am also attaching a copy of the 9patch.
What could be wrong?!
This happens:
Here is the 9patch
If the image has been created in a normal image editor rather than the android 9 patch tool, it could be just that its not done exactly right.
The image must have a 1px transparent border other than where the black lines are. Make sure its completely transparent and is only 1 px thick
Also I don't think you can have split lines (like you have down the left and right side of the image, I think they must be one solid line on each side)
Related
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've created several 9-patch images using the android draw9patch utility and I've yet to make one that works. On one image I've got 2 dots on the top edge, and 2 dots on the left edge; the 'show bad patches' button shows no bad patches, and the samples on the right side look fine. However, in the app the image appears with the black 9patch dots showing on the top and right sides.
Are we suppose to set the backgroundColor or cachecolor to hide the dots in the imageview?
I'm targeting google maps 2.3.3. Could there be known issues with this API?
What is the full name that you gave to the file? The file name must end in ".9.png" to work properly. Otherwise it will be treated as a normal png file which would display the dots and lines at the edges of the image.
Those dots will go away when they're displayed on the phone. They tell the Android System what parts of the image can be stretched without warping how it's supposed to look. If you notice the format of the 9patch is .9.png, there's preprocessing that Android does before the image is displayed and the dots are removed. 'Show Bad Patches' rarely makes a difference I've found, even if they're considered 'bad' they work how I want them too. At least in my experiences. Just add the 9patches to your activity and reference them as you normally would
Update
Wait a second. Are you trying to use 9patches as images to be displayed in an ImageView? That's not what 9patches are for. 9patches are stretchable images for buttons or other UI elements (i.e. for different screen sizes) so developers can have one image to stretch and fit the different sized buttons instead of one for each size. Android displays most image formats in ImageView. If you're displaying the 9patches with an ImageView, Android isn't preprocessing the black dots as slices of that image that are repeatable, it's just displaying the whole thing.
I'm testing on HTC Desire which is a hdpi device. The problem is clear when you look at the image:
And here is how my 9-patch (made with standard 9-patch tool) looks (zoomed):
The left image is my photoshop file, and the right one is a screenshot from my device. As you can see there is a huge difference. Let's say that the shadow is not THAT important, but the blurred border looks bad.
Is my 9-patch png wrong? What can I do to achieve a nice crisp 1px solid border?
You should use 9-path tool for each png in different drawable folder. Sometimes problem is this the Android try to convert the png and blur the black lines, what cause later problem with properly displaying.
To circumvent this problem simply drop the 9 patch inside the drawable-no-dpi folder.
This allows to have one image for all densities. And android won't touch the image.
This is mostly what I do for my projects, unless I really want to have a difference between the densities. In that case, I create one 9-patch per density.
Alternate solution:
Shrink your top and left markers by 1 pixel on each side. This will ensure that scalable part does not overlap the grey border.
Can anybody advise me on how to setup a splash screen to work cross resolution?
I have tried re-sizing a png file to different dimensions and placing the image in the ldpi,mdpi,hdpi folders, but the image still looks stretched/squashed depending on the device.
Is there a way to place a logo centre of the screen with a white background, i'm happy to use one size of logo even as long as it sits in the middle and looks ok¬?
Does anyone have any advice?
Cheers
Paul
Have you heard of/considered using a 9 patch version of the logo? A nine patch image allows you to define areas of an image which can be stretched. If you create your logo png file with a white background and then set the white area as stretchable it will then fill your container nicely but the logo part of the image will not distort at all.
In your android-sdk directory, under the tools subdirectory, execute a tool called draw9patch
./draw9patch
Drag your image in there. Use the left view for drawing pixels on the top and left sides. Use the right view for inspecting how your image will stretch on different devices.
OK, the answer has EVERYTHING to do with the stretchy areas of your 9patch image. I found the answer by pinging the github question. A user sent me to another discussion where someone had cracked it.
The main issue is that most 9patch tutorials explain how to stretch buttons, but none detail how to center an image.
Look for the green/blue/red image a little more than half way through the discussion.
http://community.phonegap.com/nitobi/topics/stretched_9_patch_splash_screens_android
The key for me was to look at the edges. It's really hard to see (for me at least), but you can barely make out the black marks along the edge that define the stretchy areas. top has 2 small areas (on the green), left has 2 small (on the green), bottom has one long (on the blue), right has one long (on the blue).
Consequently, I find this one image (as hard as it is to see the lines) a better instruction on how 9patch works than all of the tutorials I've watched.
NinePatch:
Screenshot:
Layout XML:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:background="#ffffff">
<LinearLayout
android:id="#+id/edit_tray"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true">
<View
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#drawable/trash"/>
</LinearLayout>
</RelativeLayout>
Desired Results:
The "edit_tray" represents a UI element that will be toggleable. When edit mode is off, the "edit_tray" (and therefore the trash can icon) are "gone". When edit mode is on the "edit_tray" is visible and overlaid over the ScrollView contents.
There are two elements to the trash can icon: The icon itself and the linear gradient behind it. The NinePatch image contains three stretchable areas and one static area to accommodate these elements. The trash can icon in the middle of the graphic is static and should appear directly in the horizontal center and on the bottom of the screen. The gradient should stretch across the bottom of the screen from one side to the other.
The Bug?
The NinePatch image contains only one pixel of stretchable area on either side of the image horizontally. The effect of which should be that the trash can icon appears directly in the center (1 pixel on left side == 1 pixel on right side). However, as you can see in the screenshot above that is not the case. Note: this screenshot was taken from my test phone, a T-Mobile G2. The same effect can be seen in the emulator. However, in the draw9patch preview and the eclipse Graphical Layout view the image is perfectly distributed.
I've tried several different methods to try to find out where the bug is and to try to fix it or work around it. Including: using ImageViews instead of Views (same effect), using android:scaleType="fitXY" (same issue), checking at runtime that the width of the screen and the width of the "edit_tray" are the same (they are), using two different images for gradient (as edit_tray background) and icon (as ImageView src) (create another problem where the two images were not overlayed on each other. Fixed by setting an absolute height on both), etc.
The Answer, the Workaround, and the Real Question
I did some testing using some simple NinePatch images with up to six stretchable areas per side. I noticed there were some issues displaying them in at least one of the testing cases (phone, emulator, draw9patch, Graphical Layout in eclipse).
I decided to try to expand the image horizontally so that there was more of the linear gradient showing on the edges of the trash can icon. I made the image 128x64 (previously 64x64). I made more of the edges part of the stretchable part to try to curb any bad math (?) that was happening to the image. Draw9patch reported bad sections so I put it back to just the two pixels, one on either side. It worked! The icon is directly in the center of the screen now! I don't know why, but without changing the actual stretchable portion of the image, only changing the width of the image to 128, it works now.
I tried resizing the image back down to around 100px wide to remove some of the redundant pixels and the error came back! Not only did it come back, but the icon was placed at exactly the same spot offset from the center of the screen. I can't figure out why this would happen this way.
Anyone have any ideas? Is this a bug?
I currently have this working given the workarounds I described above, but if anyone has any suggestions I'm listening.
Make your 9 Patch image with using 4 points as I have done in this..and it will work.
Tips for Creating 9 Patch Image.(not a designer,telling you my funda)
Put points on Left and Top
If you have some text or image in between ..then put point on left
and right of image and top and bottom of that image or text.
Always see the no of space left and no of points on both sides(left-right and top-bottom) are equal.
Always check once the preview or right side before using check in 2x
to 6x
From my experience with the draw 9-patch tool there is an automatic 1px offset on each side of the image. Given this information if you were using just this one pixel offset your image was actually not being stretch the way you would imagine.
This can be seen by the fact that when you used a 2px offset it worked perfect.
Also the 9-patch images have a tendency of showing up in eclipse exactly how you would think... but then appearing different on the phone/emulator.
Learning the 9-patch tool is def a great thing as it allows greater customization. Another tip, if you want to do something like replace any android 9-patch with your own alterations - then just copy the 9patch that exists in the SDK and alter it. For some reason 9patch images in the SDK have weird offsets. Doing this will guarantee you don't get weird responses from your 9-patches. An example of this - I outline an editText in red when bad input is given.
The SDK images can be found in SDK->platforms->[plateform-you-want]->data->res-drawable-[you-choice]
You can also look at the SDK 9-patch images to help understand how the 9-patch-tool works.
Hope this give a little more insight.
Here are some good links:
http://developer.android.com/guide/developing/tools/draw9patch.html
http://android10.org/index.php/articlesother/279-draw-9-patch-tutorial
http://jaanus.com/post/7878186745/how-does-androids-nine-patch-tool-work-from-a
Maybe it's bug in nine-patch drawing, or just error resulting from rounding.
However, I don't like your approach of drawing this icon. You try to position your screen element using something that is not designed for this task.
You should draw it other way: create some container view (FrameLayout) with gradiend background. Then on top of that position ImageView with trash can. Neither of these 2 images need to be nine-patch, gradiend would fill entire view, trash can would be drawn without scaling.
Although there's overdraw in area of trash view, CPU time is not wasted in nine-patch areas computations.
You would use layout system for exact positioning of your trash icon. Certainly you would get expected result, since UI layouts are well tuned, and made for purpose of positioning screen elements. Nine-patch images are used for other purpose (where pixels shifted here or there a bit should not matter).
As #jjNford said - it's bad practice to work with images in this way.
For this task the best solution is to create "trash" icon with transparent background, and create shape drawable with gradient. So, you can remove unnecessary LinearLayout and use only ImageView:
<ImageView
android:id="#+id/edit_tray"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:src="#drawable/trash"
android:background="#drawable/gradient_background"/>
Docs for shape drawable.
EDIT
Just check your image - it starches fine on SE Xperia 2.3.3