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
有时，手动创建R.java文件会有帮助，只是简单的空R.java。
其他回答
R是一个生成的类。如果你正在使用Android开发工具(ADT)，它会在项目构建时生成。您可能已经关闭了“自动构建”。
对我来说，我删除了“import android.R;”，它解决了我所有的问题。真是个噩梦!!
如果清理项目不起作用，如果xml文件没有问题(如果它是一个新项目)。然后转到Androidmanifest.xml，编辑它并在行之间添加一些空格，保存它。现在清理项目，错误将消失。
这是因为陈旧的R.java文件。当我们编辑android manifest文件时，再次创建R.java。
I would say "R can not be resolved" is something too general and can be misleading at times. I also had the same problem many times ago even when I first create a new project (which mean I did not mess with the code yet). Most of the time I just need to update my sdk manager (as some people have mentioned). But in my recent case, I found out that the path to my project file is too long (something like this E:\R&D\ANDROID\ANDROID BASIC\Folder 1\ Folder 2\..... \Folder n\MyProject). The folder names also contain spaces character. I thought it could be the case and indeed it's true, when I created a new project in another folder with shortest path possible, and none of the folders' names containing space character, it worked as normal.
还有一件事可能会导致这个问题:
我安装了新的ADT(第22节)。它停止创建包含R.java的gen文件夹。解决方案是在Android SDK管理器中安装新的Android SDK构建工具。
在这里找到解决方案
