Develop Reference

Android ImageButton display error

I am developing an android app, I am trying to use the android image button. I have placed my image in the drawable folder and have this in my xml code:
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/PanicBtn"
android:layout_marginTop="53dp"
android:src="#drawable/panicbtn2"
android:background="#ffffffff"
android:contentDescription="" />
but each time I try to clean or debug the project, i keep getting this error:
Error:(28, 22) No resource found that matches the given name (at 'src' with value '#drawable/panicbtn2').
Kindly help.

Sometimes, keeping the resource or image in your case in Drawable folder doesn't get added to ItemGroup/resource group.
You can simply open the .csproj file of your project and validate that if the image name is present in the < ItemGroup > section.. it must be like below if your image name and extension is panicbtn2.png:
<AndroidResource Include="Resources\drawable\panicbtn2.png" />
If it's not present there, then you can add the same there or you can right click the drawable folder and choose add files and simply add the file again through IDE/Visual Studio. That might help.

The error already states:
No resource found that matches the given name
Have you place a resource in drawable with that specific name "panicbtn2"?
Cheers.

Failed to convert drawable into a drawable

I'm getting the error "Failed to convert #drawable/12234 into a drawable" where 12234 is my image name, that is placed inside the drawable folder.
I'm able to assign other images that are smaller, however when I try to assign this image it gives me an error.
Here is my code for my Imageview xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/imageView4"
android:layout_alignParentTop="true"
android:src="#drawable/12234"
android:adjustViewBounds="true"
android:longClickable="true"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignParentBottom="true" />

According to documentation drawables resources must satisfy the following:
File-based resource names must contain only lowercase a-z, 0-9, or _.
And also in your case it cannot be all numbers, it has to have at least one letter.

I solved the issue by renaming the image to have a character first.
Changed image name from 12234.jpg to r12234.jpg

In Adroid Studio's Design View, try just clicking the refresh icon, the one that looks like two curved arrows facing each other.
This worked for me - I didn't need to rename anything or restart my computer.
I'm running ver 1.5.1, Marshmallow, API 23.

I have been stumbling for many hours, read almost all answers on all questions but nothing worked. Finally, I have found a solution that worked.
What i did
Showed "drawable" in explorer
Replaced ALL ı's with i's (drawable-hdpı -> drawable-hdpi, renamed
all folders) Then the folders didn't appear in android studio
Replaced only 2 i's with ı's (drawable-hdpi -> drawable-hdpı, renamed
2 folders) Afterwards, all the images started to appear and finally
i was able to add images.

R doesn't generate button

I've just finished to do the layout I want, and even although I saved everything, when I try to find by id the button, the button I'm looking for is missing.. Both the button's I have.. I've checked in the R class, under the ID, and it seems it doesn't sees' the buttons. Doesn't generate them? I dunno.. Any way, it happens every time I use relative layout!! Is there any connection? It works with TableLayout and with linear layout.. Only with relative layout it make's problems.
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#drawable/Background" >
<TextView
android:id="#+id/corpTag"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:text="#string/corpTag"
android:textColor="#color/White" />
<Button
android:id="#+id/addBusinessButton"
style="#android:style/ButtonBar"
android:layout_width="200dp"
android:layout_height="25dp"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="208dp"
android:text="#string/addYourBusiness" />
<Button
android:id="#+id/searchBusinessButton"
style="#android:style/ButtonBar"
android:layout_width="200dp"
android:layout_height="25dp"
android:layout_alignBottom="#+id/addBusinessButton"
android:layout_alignLeft="#+id/addBusinessButton"
android:layout_marginBottom="36dp"
android:text="#string/searchBusiness" />

I found this happening to me with a broken layout. No need to be worry. I am trying my best to giving you the solution
Solution
Make sure that anything the R. links to is not broken. Fix all errors in your XML files. If anything in the ADKs are broken, R will not regenerate.
If you somehow hit something and created import android.R in your activity, remove it.
Run Project -> Clean. This will delete and regenerate R and BuildConfig.
Make sure Project -> Build Automatically is ticked. If not, build it manually via Menu -> Project -> Build Project .
Wait a few seconds for the errors to disappear.

This problem isn't related to relative layout, but is actually set on the background because Android drwable is case-sensitive and now allows you any capital letters for image or layout. Rename your image name or drwable name to "background" instead of Background."
Here is the problem with set background name:
android:background="#drawable/Background"

It might be the Android Style ButtonBar. It isn't available for every API level. So if you have a low minSDK, it's not going to build and Eclipse/IntelliJ should give you an error message in its error pane.
The rule given by Google, is that you should always define your own resources. If you want to use a resource that is in the Android name space, that's fine, but you should copy it first and package it with your apk, because that's the only way you can be assured that it will always be bundled with your application.
And yes, I realize many people and many tutorials on the web don't do it that way, but that's because most people are lazy.

could not resolve resource android eclipse

I am new in andorid development.
I have created my android first project according to http://developer.android.com/training/basics/firstapp/creating-project.html
And here is the code that I have as the project was created(no changes are done in code by me)
<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"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/hello_world" />
</RelativeLayout>
Here is the screenshot of the Graphical layout
http://imageshack.us/a/img35/5284/android1s.png
So, it looks fine for now, but if I want to change the text Hello world to , say, hello, so the code's part looks like android:text="#string/hello", I get the error
NOTE: This project contains resource errors, so aapt did not succeed, which can cause rendering failures. Fix resource problems first.
and
Couldn't resolve resource #string/hello, and the text in graphical layout becomes
#string/hello, as it is in this image
http://imageshack.us/a/img826/7735/android2p.png
But I noticed one thing:
If after this error I go to res/values/strings.xml and add String with name and value hello, like
http://img842.imageshack.us/img842/8108/android3s.png
The error disappears and I can see the word hello in the graphical layout.
I tried these so far
Using ctrl+shift+s like it is described here https://stackoverflow.com/a/14462434/932473
Closing and reopening Eclipse.
cleaning, rebulding
removing the entire project and creating again.
The values folder does exist in res.
None of these questions solved my problem
Eclipse could not resolve string resource error
Can't Resolve Android Resource Strings
UPDATED
If I write like this android:text="hello"
I get this warning in eclipse
Hardcoded string "hello", should use #string resource,
I do not get it every time I want to use some string like android:text="#string/hello2", I have to first manually specify hello2 it in strings.xml ?

In res/values/strings.xml
<string name="hello">Hello</string>
Then refer the string in your textview as
android:text="#string/hello"
I guess you do not have something similar to above. Hence you get resource not found exception coz the resource is not defined in strings.xml
or
You can do as below
<string name="hello_world">hello</string> // change the string in strings.xml
android:text="#string/hello_world"
For the question in the comment

You can just use
android:text="hello"
the #string bit means its a resource called hello in your xml.
So you can also add the resource to your xml if you wish. Its known to be better practice, for internationalization.

Build Simple UI Lesson Sample

Ok, I have been following a lesson sample at the Android Developer site and the code was thus:
<LinearLayout 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"
android:orientation="horizontal">
<EditText android:id="#+id/edit_message"
android:layout_weight="1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:hint="#string/edit_message" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/button_send" />
</LinearLayout>
Apparently, the code should be fine, after worrying I typed it in wrong, I ended up copying it directly but the Console is telling me:
Description
error: Error: No resource found that matches the given name (at 'hint' with value '#string/edit_message').
Description
error: Error: No resource found that matches the given name (at 'text' with value '#string/button_send').
Now these values are defined in the strings.xml file. So I have no idea why I would be getting these errors.
To anyone who can help here is a big thank you in advance.

Try in eclipse project>clean . Sometimes eclipse give you errors like these. Or restart eclipse. Did you also make sure at your strings.xml you have something like this ?<string name="edit_message">Your intresting string.</string> sometimes if you use the 'gui resource adder' It gives mistakes. Check inside your xml.

make sure there is no capital characters or underscores in any file inside res.
Also , there must no any error inside the files of res and src ..
after that you have to clean the project as mentioned in previous answer.
Actually these errors prevent the R file to be updated which is necessary to access resources inside res file.