发送的广播事件可被其他应用程序获取，也能响应其他应用程序发送的广播事件（可以通过 exported–是否监听其他应用程序发送的广播 在清单文件中控制） 全局广播既可以动态注册，也可以静态注册。
默认发送的广播,就是全局广播,所有的App都可以请求接受
发送的广播事件不被其他应用程序获取，也不能响应其他应用程序发送的广播事件。 本地广播只能被动态注册，不能静态注册。动态注册或方法时需要用到LocalBroadcastManager。
本地广播案例 1,注册一个广播
package com.example.day013; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.util.Log; public class MyReceiver extends BroadcastReceiver { private static final String TAG = "MyReceiver"; @Override public void onReceive(Context context, Intent intent) { Log.i(TAG, "onReceive: "); } }java代码
package com.example.day013; import android.content.Intent; import android.content.IntentFilter; import android.support.v4.content.LocalBroadcastManager; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.Button; public class MainActivity extends AppCompatActivity implements View.OnClickListener{ private Button send; private LocalBroadcastManager localBroadcastManager; private MyReceiver myReceiver; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); send = findViewById(R.id.send); send.setOnClickListener(this); //创建一个本地广播 localBroadcastManager = LocalBroadcastManager.getInstance(this); //动态注册一个广播 myReceiver = new MyReceiver(); IntentFilter intentFilter = new IntentFilter(); intentFilter.addAction("com.feng"); localBroadcastManager.registerReceiver(myReceiver,intentFilter); } @Override public void onClick(View v) { int id = v.getId(); switch (id) { case R.id.send: Intent intent = new Intent(); intent.setAction("com.feng"); //注意广播的发送者 localBroadcastManager.sendBroadcast(intent); break; default: break; } } @Override protected void onDestroy() { super.onDestroy(); //有注册就有销毁 localBroadcastManager.unregisterReceiver(myReceiver); } }本地广播的优点：
可以明确的知道正在发送的广播不会离开我们的程序，不用担心机密数据泄露 其他程序无法将广播发送到我们的程序内部，不需要担心安全问题 发送本地广播比系统全局的广播效率高
BroadCastReceiver和Notifcation 1,注册一个广播.(静态或者动态都可以.代码省略) 2,广播的内容.
package com.example.day013; import android.app.Notification; import android.app.NotificationManager; import android.app.PendingIntent; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.util.Log; public class MyReceiver extends BroadcastReceiver { private static final String TAG = "MyReceiver"; @Override public void onReceive(Context context, Intent intent) { Log.i(TAG, "onReceive: "); Notification.Builder builder = new Notification.Builder(context); builder.setAutoCancel(true); builder.setSmallIcon(R.mipmap.ic_launcher); builder.setContentText("标题"); builder.setContentText("内容"); //可弹出 builder.setPriority(Notification.PRIORITY_MAX); builder.setDefaults(Notification.DEFAULT_ALL); //可跳转 Intent intent1 = new Intent(context,Main2Activity.class); PendingIntent activity = PendingIntent.getActivity(context, 0, intent1, PendingIntent.FLAG_CANCEL_CURRENT); builder.setContentIntent(activity); Notification build = builder.build(); NotificationManager manager =(NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE); manager.notify(1,build); } }使用BroadCastReceiver发送消息更新UI 注意 需要动态注册广播 注意 需要动态注册广播 注意 需要动态注册广播 需求, 点击一个按钮,换一个图片 布局xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" tools:context=".Main2Activity"> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/updata_ui_id" android:text="更新一个图片" /> <ImageView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/image_id" android:src="@mipmap/ic_launcher" /> </LinearLayout>Activity代码
package com.example.day013; import android.content.Intent; import android.content.IntentFilter; import android.os.Handler; import android.os.Message; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.ImageView; public class Main2Activity extends AppCompatActivity { private Button updataUiId; private ImageView imageId; private MyReceiver2 myReceiver2; private Handler handler = new Handler(){ @Override public void handleMessage(Message msg) { super.handleMessage(msg); } }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main2); updataUiId = findViewById(R.id.updata_ui_id); imageId = findViewById(R.id.image_id); myReceiver2 = new MyReceiver2(handler,imageId); IntentFilter intentFilter = new IntentFilter(); intentFilter.addAction("com.feng.ui"); registerReceiver(myReceiver2,intentFilter); updataUiId.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Intent intent = new Intent(); intent.setAction("com.feng.ui"); sendBroadcast(intent); } }); } @Override protected void onDestroy() { super.onDestroy(); unregisterReceiver(myReceiver2); } }广播接受这的代码
package com.example.day013; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.os.Handler; import android.widget.ImageView; public class MyReceiver2 extends BroadcastReceiver { private Handler handler; private ImageView imageView; public MyReceiver2(Handler handler, ImageView imageView) { super(); this.handler = handler; this.imageView = imageView; } @Override public void onReceive(Context context, Intent intent) { String action = intent.getAction(); if ("com.feng.ui".equals(action)){ handler.post(new Runnable() { @Override public void run() { imageView.setImageResource(R.mipmap.ic_launcher_round); } }); } } }官方文档
https://github.com/greenrobot/EventBus
翻译文档
https://www.jianshu.com/p/e7d5c7bda783
