错误一：

[Please check logcat output for more details.
Launch canceled!

解决办法：
在配置文件：AndroidManifest.xml加入如下代码：
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.android.demo"
android:versionCode="1"
android:installLocation="auto"//加上这就ok
android:versionName="1.0" >

错误二：

The connection to adb is down, and a severe error has occured.
You must restart adb and Eclipse.
Please ensure that adb is correctly located at 'D:\java\sdk\platform-tools\adb.exe' 

关闭eclipse

进入dos命令

netstat -aon|findstr "5037"
TCP 127.0.0.1:5037 0.0.0.0:0 LISTENING 6540
发现6540占用了 5037端口，继续查看6540的task，发现是wandoujia .如下所示
tasklist|findstr "6540"
去任务管理器杀死对应的进程，启动eclipse。