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

如果您使用的是Mac,请检查. ds_store是否已添加到/res目录中(终端命令行中的ls -al)。删除它并刷新/重建。

其他回答

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.

检查你导入到应用程序中的库项目是否都是打开的。

出于某种原因,如果你没有向活动添加任何东西,比如onCreate(),它就不会理解R是什么。

我用窗口->首选项->Android和SDK解决了这个问题,位置:adt\ SDK的路径,例如C:\adt\ SDK

一些答案建议重新启动计算机。我发现重启adb服务器就足够了——如果你刚刚更新了Android SDK,这一点尤其正确。

通过linux shell重启adb:

$ cd $ANDROID_SDK/platform-tools
$ ./adb kill-server
$ ./adb start-server

您可能需要重新启动Eclipse,以便重新连接到重新启动的adb服务器。如果Eclipse没有自动编译项目,您可能需要执行一个clean/build。

我尝试了上面的大多数方法,但对我的情况不起作用

最后我发现adb输了

对于MAC OS,进入android SDK目录

输入。/adb start-server