R无法解决- Android错误

我刚刚下载并安装了新的Android SDK。我想创建一个简单的应用程序来测试它。

向导创建了以下代码:

package eu.mauriziopz.gps;

import android.app.Activity;
import android.os.Bundle;

public class ggps extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }
}

但是Eclipse给出了错误

R不能被分解

在网上

setContentView(R.layout.main);

Why?

PS:我在res/layout/下有一个名为main.xml的XML文件。

当前回答

我也有同样的问题。在我的情况下，必须与布局XML文件名。我有一些大写字母的文件名:

xml -没有工作!

xml -正常工作!

2010-09-20 06:38:37

其他回答

我按照建议安装了平台构建工具。然后的消息

<package>/gen already exists but is not a source folder. Convert to a source folder or rename it.

出现在控制台。所以我听从了建议，将“gen”设置为源文件夹。这解决了问题。

2013-11-10 12:27:01

R.java是Android Eclipse插件创建的文件构建应用程序。R.java是在“gen”下创建的目录中。此文件由“res”中的信息生成。目录中。如果在Eclipse上运行select“Project”->“Clean… 菜单，它将删除，然后重新生成R.java文件。

“R不能被解决”的问题发生在你改变你的在AndroidManifest.xml文件中的包名。它使用安卓系统包名下创建子目录“gen”目录，其中它存储R.java文件。

Eclipse may have problems executing clean, because it is confused about where the R.java file is when you have changed the Android package name. You can either rename the subdirectory under gen to match your new package name, or you can change your package name back to the old name. Do the clean and then change the package name to the new name you want. This works best if you stop Eclipse from trying to build while you are changing the package name. Under the "Project" menu uncheck the option to "Build Automatically" and also when the "Clean..." dialog asks if it should "Start a build immediately" uncheck the box so it doesn't try to build while you are changing the package name. After you have changed the name you can turn "Build Automatically" back on again.

Note that if your AndroidManifest.xml file package name does not match your Java package name, Eclipse will end up automatically adding an "import <your Android package name>.R;" line in all your .java files that have any references to R. If you change your AndroidManifest.xml package name, sometimes Eclipse does not update all of these added imports. If that happens, use the Eclipse refactoring (ALT + Shift + R) to change the import statement in one of your Java files to your new AndroidManifest.xml package name. It is best to do this while you have disabled "Build Automatically".

2010-03-04 18:37:14

我的项目有一个r.java.在开始，R.layout。主要工作好。但是，在添加了一些代码后，它不能工作，错误是r.b ayout.main不能解决。有什么问题吗?

查看您的导入。很有可能这句话是: