Android_03--四大组件_Activity+BroadcastReceiver+service+ContentProvider
1.Activety活动创建Activity定义Activity定义类继承Activity在AndroidManifest.xml的节点中声明显示意图创建构造函数,代码少newIntent(this,NewActivity.class);类名形式,灵活,可扩展性强intent.setClassName(this,"cn.itcast.activity.NewActivity");包名类名形式,可启