Question

Has anyone ever used the hidden class PackageParser in Android source code with java reflection?

I can get this class and its method collectCertificates() in the reflection way, but I keep getting the NoSuchMethodException with its method generatePackageInfo().

I am wondering whether the following sentence causes that problem, since I am not so sure about the usage of int[].class:

partypesGeneratePackageInfo[1] = int[].class;

Here is my code:

    private PackageInfo parsePackage(String archiveFilePath, int flags)
        throws Exception, Exception {
    // get class:PackageParser
    Class clsPackageParser = Class
            .forName("android.content.pm.PackageParser");

            ......      

    // get method:collectCertificates
    Class partypesCollectCertificates[] = new Class[2];
    partypesCollectCertificates[0] = clsPackage;
    partypesCollectCertificates[1] = int.class;
    Method methCollectCertificates = clsPackageParser.getMethod(
            "collectCertificates", partypesCollectCertificates);

    // invoke method:collectCertificates
    Object arglistMethCollectCertificates[] = new Object[2];
    arglistMethCollectCertificates[0] = objPackage;
    arglistMethCollectCertificates[1] = flags;
    methCollectCertificates.invoke(objPackageParser,
            arglistMethCollectCertificates);

    // get method:generatePackageInfo
    Class partypesGeneratePackageInfo[] = new Class[3];
    partypesGeneratePackageInfo[0] = clsPackage;
    partypesGeneratePackageInfo[1] = int[].class;
    partypesGeneratePackageInfo[2] = int.class;
    Method methGeneratePackageInfo = clsPackageParser.getMethod(
            "generatePackageInfo", partypesGeneratePackageInfo);

    ......
}

Answer 1

For what I can see, the declaration for generatePackageInfo is:

public static PackageInfo generatePackageInfo(PackageParser.Package p,
        int gids[], int flags, long firstInstallTime, long lastUpdateTime) {

So that’s 5 parameters: PackageParser.Package.class, int[].class, int.class, long.class, long.class.

Since this is not an exposed API, it could very well be that the number of parameters changes from version to version.