Android earlier version projects (such as 1.6) are put into a later version environment (such as 2.2) Solution

If an android earlier version Project (such as Android 1.5) is placed in a later version environment (such as Android 2.2), the preceding error may occur. The solution is as follows:
1. If you do not modify the android SDK version, use the Project Clean command to act on a project.
(This processing method is only compatible with lower-version projects in the high version and is not truly upgraded)
2. To modify the android SDK version, follow these steps:
1) modify the SDK
Select the project, build path --> Configure build path ---> library to delete the referenced low-version SDK,
Add external jars, select SDK of later version, OK, and save
2) modify the classpath File
This file may contain this item: <classpathentry kind = "lib" Path = "Your specified High Version address"
Change her to <classpathentry kind = "con" Path = "com. Android. Ide. Eclipse. ADT. android_framework"/>
3) Modify androidmanifest. xml
In the androidmanifest. xml file, add the <uses-SDK Android: minsdkversion = "3"> </uses-SDK>
4) Modify default. properties (important)
Target = Android-3 in the last line of the file (not used in the previous step), and save it as target = Android-8.
Let's take a look at your project and the new Android 2.2 project structure.