PackageManager和ActivityManager的区别上文档:/** * Class for retrieving various kinds of information related to the application * packages that are currently installed on the device. * * You can find this class through */public abstract class PackageManager /** * Interact with the overall activities running in the system. */public class ActivityManager PackageMAnager可以获取系统上所有安装App的各种信息,比如图标,名字,内存占用,签名,权限信息等等;ActivityMAnager管理系统运行的当前Activity,比如有哪些task在运行,运行的服务,进程等;