以下是ComponentName的API

   /*** Create a new component identifier from a Context and Class object.* * @param pkg A Context for the package implementing the component, from* which the actual package name will be retrieved.* @param cls The Class object of the desired component, from which the* actual class name will be retrieved.*/public ComponentName(Context pkg, Class<?> cls) {mPackage = pkg.getPackageName();mClass = cls.getName();}

ComponentName（组件名称）可以用来打开其他应用程序中的Activity或服务。

Intent it=new Intent();  
it.setComponent(new ComponentName(String packageName,String activityName ));  
startActivity(it);