具体步骤：

1、初始化广播接收器BroadcastReceiver，接收到的广播会在该类的onReceive方法中回调

2、注册广播registerReceiver(BroadcastReceiver,IntentFilter);

3、发送广播sendBroadcast(Intent);


此demo是为了验证已经被覆盖的Activity在接收到广播时能否自己更新UI，下面是具体代码：

第一步，创建MainActivity，并初始化广播接收器BroadcastReceiver、注册广播

publicclassMainActivityextendsAppCompatActivity{privateTextViewtipTv;publicstaticfinalStringACTION_NAME="TAG_MAIN";@OverrideprotectedvoidonCreate(BundlesavedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);tipTv=(TextView)findViewById(R.id.tipTv);findViewById(R.id.gotoTv).setOnClickListener(newView.OnClickListener(){@OverridepublicvoidonClick(Viewv){Intentintent=newIntent(MainActivity.this,SecondActivity.class);startActivityForResult(intent,100);tipTv.setText("等待接收广播。。。");}});//注册广播registerBoradcastReceiver();}//广播接收器privateBroadcastReceivermBroadcastReceiver=newBroadcastReceiver(){/***广播接收器，接收到广播的回调方法*@paramcontext*@paramintent*/@OverridepublicvoidonReceive(Contextcontext,Intentintent){Log.d("myp","===broadcastcallback===");Stringaction=intent.getAction();if(action.equals(ACTION_NAME)){//当接收到广播时，Toast会在最上层的Activity中提示，Toast.makeText(MainActivity.this,"broadcastcallback",Toast.LENGTH_SHORT).show();Stringresult=intent.getStringExtra("yaner");tipTv.setText(result);//当接收到广播时，Dialog会在接收到广播的界面提示，并且会随着该界面中的业务逻辑隐藏，//由此可见，当Activity备覆盖式，如果又出发该Activity业务逻辑的操作，会在该Activity中正常执行initDialog();Timertimer=newTimer();timer.schedule(newTimerTask(){@Overridepublicvoidrun(){if(dialog!=null&&dialog.isShowing())dialog.dismiss();}},3*1000);}}};Dialogdialog;/***初始化弹出框*/privatevoidinitDialog(){dialog=newDialog(this);dialog.setContentView(R.layout.view_dialog);dialog.show();}/***注册广播*/publicvoidregisterBoradcastReceiver(){IntentFilterfiler=newIntentFilter();//筛选条件filer.addAction(ACTION_NAME);//设置要注册的广播的标签//注册广播registerReceiver(mBroadcastReceiver,filer);Log.d("myp","===broadcastregist===");}}


第二步，创建SecondActivity，并SecondActivity里实现触发 能发送广播到

MainActivity里的广播的事件

publicclassSecondActivityextendsActivity{@OverrideprotectedvoidonCreate(BundlesavedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.activity_second);findViewById(R.id.brodcastBtn).setOnClickListener(newView.OnClickListener(){@OverridepublicvoidonClick(Viewv){IntentmIntent=newIntent(MainActivity.ACTION_NAME);mIntent.putExtra("yaner","接收广播成功！！！");//接收到广播时，携带的数据//发送广播sendBroadcast(mIntent);Log.d("myp","===broadcastsend===");}});}}


xml布局文件比较简单，就不给出了，运行效果：

1、点击按钮后，Toast提示在SecondActivity里直接提示

2、点击按钮后，在3秒内返回MainActivity，Dialog正常显示，3秒过后消失

3、点击按钮后，在3秒后返回MainActivity，Dialog已经消失


结论：被覆盖的Activity在接收到广播时能自己能更新UI