How to modify Android SDK in the project of the high jar package

If the android application installation package APK is developed on a later android jar, it cannot be run on a later android SDK, therefore, we need to replace the developed application with an android jar package of a lower version to re-compile an APK. How can we simply modify it directly in the High Version project:

1. In eclipse, click "project"> "Properties"> "Android". Select "Android 2.2" on the right side of the page (provided that your android sdk contains both android jar packages)
Or open default. properties file. In the root directory of the project, change target = android-10 (2.3) to target = android-8 (2.2 ), in this way, the original android jar 2.3 is changed to android jar 2.2. Save the changes. eclipse automatically replaces android jar 2.3 with android jar 2.2 in the project.
2. Open the AndroidManifest. xml file and change <uses-sdk android: minSdkVersion = "10"/> to <uses-sdk android: minSdkVersion = "8"/> to save the file.
3. recompile the project to generate an APK:
Menu Bar-> Project-> Clean
You can run this application on android V2.1.
4. If a class not found error occurs, remember to select all third-party jar packages, add to build path, select the lib directory, and use as source.
Then, choose "Project"> "Clean" from the menu bar.

The error cannot be found in third-party jar packages.