public interface OnInstalledPackaged {

public void packageInstalled(String packageName, int returnCode);

}

第二步，定义一个系统不可见的接口IPackageInstallObserver，所以包名是不能变的

package android.content.pm;

public interface IPackageInstallObserver extends android.os.IInterface {

public abstract static class Stub extends android.os.Binder implements android.content.pm.IPackageInstallObserver {
public Stub() {
throw new RuntimeException("Stub!");
}

public static android.content.pm.IPackageInstallObserver asInterface(android.os.IBinder obj) {
throw new RuntimeException("Stub!");
}

public android.os.IBinder asBinder() {
throw new RuntimeException("Stub!");
}

public boolean onTransact(int code, android.os.Parcel data, android.os.Parcel reply, int flags)
throws android.os.RemoteException {
throw new RuntimeException("Stub!");
}
}

public abstract void packageInstalled(java.lang.String packageName, int returnCode)
throws android.os.RemoteException;
}

第三步，实现ApplicationManager功能

import java.io.File;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import android.content.Context;
import android.content.pm.IPackageInstallObserver;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.os.RemoteException;

public class ApplicationManager {
public final int INSTALL_REPLACE_EXISTING = 2;
public static final int INSTALL_SUCCEEDED = 1;

private PackageInstallObserver observer;
private PackageManager pm;
private Method method;

private OnInstalledPackaged onInstalledPackaged;

class PackageInstallObserver extends IPackageInstallObserver.Stub {

public void packageInstalled(String packageName, int returnCode) throws RemoteException {
if (onInstalledPackaged != null) {
onInstalledPackaged.packageInstalled(packageName, returnCode);
}
}
}

public ApplicationManager(Context context) throws SecurityException, NoSuchMethodException {

observer = new PackageInstallObserver();
pm = context.getPackageManager();

Class< >[] types = new Class[] {Uri.class, IPackageInstallObserver.class, int.class, String.class};
method = pm.getClass().getMethod("installPackage", types);
}

public void setOnInstalledPackaged(OnInstalledPackaged onInstalledPackaged) {
this.onInstalledPackaged = onInstalledPackaged;
}

public void installPackage(String apkFile) throws IllegalArgumentException, IllegalAccessException, InvocationTargetException {
installPackage(new File(apkFile));
}

public void installPackage(File apkFile) throws IllegalArgumentException, IllegalAccessException, InvocationTargetException {
if (!apkFile.exists()) throw new IllegalArgumentException();
Uri packageURI = Uri.fromFile(apkFile);
installPackage(packageURI);
}

public void installPackage(Uri apkFile) throws IllegalArgumentException, IllegalAccessException, InvocationTargetException {
method.invoke(pm, new Object[] {apkFile, observer, INSTALL_REPLACE_EXISTING, null});
}

}