R.Java not generated | 易学教程

问题

I have downloaded code from google codes but when I import that project in my eclipse IDE it does not generate R.Java file.I searched many blogs and forums and tried many things like cleaning ,rebuilding, creating project from existing source etc but still facing the problem.Some people mentioned that it is sometimes caused by the SVN client software,but none of them mentioned any solution for that.I will be very thankful to you guys if you download it yourself and find what is the exact problem.

回答1:

In general, to make it work:

import project into eclipse (File -> Import -> General -> Existing Projects into Workspace)
in Eclipse, Manually create gen folder and add it as source folder (right click on your project, Build Path -> Configure Build Path -> Add folder)
Clean your project, you suppose to get R.java generated

But It doesn't, Why?

Because there are some compile error (or bug?) regarding to the xml file in res, so R is not genetared (I've tested on my Mac):
In res/values/styles.xml: commented out the following:

<style name="iWindowTitleBackground" parent="android:WindowTitleBackground">    
  <item name="android:background">@drawable/title_bar</item>        
</style>

In res/values/themes.xml: comment out the following:

<item name="android:windowTitleBackgroundStyle">@style/iWindowTitleBackground</item>

Then do a Project -> Clean, you should get R.java generated.

There is bug reported that parent="android:WindowTitleBackground" cannot be resolved in some operating system, check out here for more details.

回答2:

Whenever your generated R class isn't generated, it indicates that there's a problem with generating it due to some parsing issue from the XML resources. Check the error console in your IDE to figure out what's specifically wrong.

Common problems are:

An unescaped character in your strings.xml, for instance you're instead of you\'re
Missing layout_width or layout_height tags in layout resources
Missing namespace declarations
Variable names that aren't supported by Java, for instance due to capitalization or use of spaces, hyphens or other unsupported characters
Any other kind of syntax error in XML
Check Console for the Issues (Image is attached where console is defining the issue why R is not generating in your project)

回答3:

When i come across this problem I delete the gen folder and it will be recreated with all the r files

回答4:

you will see at the top of your file it says import android.r or r.java i forget. you need to remove this line, clean the project, and rerun.
basically android uses R to reference items within your project. but when that import statement is there it overrides looking at your project directories and uses androids

回答5:

I encountered the same problem trying to build the wiktionary sample code I downloaded from code.google.com (here) I had imported into a new Eclipse Juno project set to use Android 4.1 and JDK 1.6.

Here is an excerpt of the console after building the project:

W/ResourceType( 6292): Bad XML block: header size 103 or total size 0 is larger than data size 0 C:\Development\WorkJava\android\sampleapps\Wiktionary\com.example.android.wiktionary.LookupActivity\res\values\strings.xml:23: error: Multiple substitutions specified in non-positional format; did you mean to add the formatted="false" attribute? C:\Development\WorkJava\android\sampleapps\Wiktionary\com.example.android.wiktionary.LookupActivity\res\values\strings.xml:23: error: Unexpected end tag string

Here's an excerpt of the res/values/string.xml:

<resources>

<string name="app_name">Wiktionary Word of the Day</string>
<string name="app_descrip">A fast Wiktionary browser and Word-of-day widget</string>
<string name="app_credits">"All dictionary content provided by Wiktionary under a GFDL license.  http://en.wiktionary.org\n\nIcon derived from Tango Desktop Project under a public domain license.  http://tango.freedesktop.org".</string>
<string name="template_user_agent">"%s/%s (Linux; Android)"</string>
<string name="template_wotd_title">"Wiktionary:Word of the day/%s %s"</string>
<string name="template_wotd_archive_title">"Wiktionary:Word_of_the_day/Archive/%s/%s"</string>

SOLUTION

Adding formatted="false" to the 3 last string definitions (containing two %s substitution placeholders), as shown below, solved the problem. Rebuilding the project generated R.java in the gen folder.

<resources>

<string name="app_name">Wiktionary Word of the Day</string>
<string name="app_descrip">A fast Wiktionary browser and Word-of-day widget</string>
<string name="app_credits">"All dictionary content provided by Wiktionary under a GFDL license.  http://en.wiktionary.org\n\nIcon derived from Tango Desktop Project under a public domain license.  http://tango.freedesktop.org".</string>
<string name="template_user_agent" formatted="false">"%s/%s (Linux; Android)"</string>
<string name="template_wotd_title" formatted="false">"Wiktionary:Word of the day/%s %s"</string>
<string name="template_wotd_archive_title" formatted="false">"Wiktionary:Word_of_the_day/Archive/%s/%s"</string>

回答6:

I still had this error after checking that all my resources had no errors, cleaning, rebuilding, restarting, etc.

I fixed this by filtering out the SVN files from the project.

How to exclude .svn directories from search in Eclipse?

While the question mentions search, the solution pertains to what files are used in compiling as well.

Restarted, and everything was fine.

回答7:

".xml files" and "image files" and make sure that the names of the lowercase.

回答8:

Change the workspace to new directory and set its permissions such that it is available for everyone

回答9:

In my case, i found an image file name containing an uppercase inside res/drawable. after changing the image name. it was solved and i could build the project