A solution for Java. Lang. noclassdeffounderror

During the development process, the following problem occurs: Java. lang. noclassdeffounderror: Android. support. v4.util. sparsearraycompat. This problem is very strange. The jar package has been installed and the compilation has passed. However, the class cannot be found during running. Noclassdeffounderror is generally the corresponding class and is not included in the corresponding APK. Isn't the corresponding android-support-v4.jar not packaged into the APK? With a try, open the project Property setting interface:

Check the check box before [Android private libraries], clean the project, and compile and run it.

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