一、接收广播

（1）用法简介

首先继承BroadcastReceiver，需要重写onReceive方法（两个参数：1.context，2.intent），然后通过registerReceiver方法注册，需要传两个参数，一个是BroadcastReceiver的实例，另一个是IntentFilter的实例，IntentFilter的实例用addAction设置Action。(有两种注册方式，静态动态，由于静态越来越不推荐了，这里只说动态注册)
系统常用的广播

（2）代码示例

public class MainActivity extends AppCompatActivity {
TextView tv;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv=findViewById(R.id.tv);
         MyBroadcastReceiver receiver=new MyBroadcastReceiver();
         IntentFilter filter=new IntentFilter();
         filter.addAction(Intent.ACTION_SCREEN_ON);
         registerReceiver(receiver,filter);//动态注册
    }
    public class MyBroadcastReceiver extends BroadcastReceiver {
        public void onReceive(Context context, Intent data){
            if(data.getAction().equals(Intent.ACTION_SCREEN_ON)){
             tv.setText("屏幕被打开");
            }
        }
    }
}

（3）运行结果

接收屏幕被打开的广播

二、发送无序广播

广播分为有序广播和无序广播，无序广播广播一发出几乎广播接收者几乎同时接收到，接到广播的先后是随机的，有序广播是一级一级接收的优先级高的先接收，并且可以拦截

（1）使用介绍

新建Intent，在Intent里设置Action（setAction),然后调用sendBroadcast(intent)就完成了

（2）代码示例

//创建一个按钮，一点击就发送广播，然后被自己的广播接收者接收
public class MainActivity extends AppCompatActivity {
TextView tv;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv=findViewById(R.id.tv);
         MyBroadcastReceiver receiver=new MyBroadcastReceiver();
         IntentFilter filter=new IntentFilter();
         filter.addAction("com.hello.world");
         registerReceiver(receiver,filter);

    }
    public void click(View v){
        Intent intent=new Intent();
        intent.putExtra("data","hello,world");
        intent.setAction("com.hello.world");
        sendBroadcast(intent);
    }
    public class MyBroadcastReceiver extends BroadcastReceiver {
        public void onReceive(Context context, Intent data){
            if(data.getAction().equals("com.hello.world")){
             tv.setText(data.getStringExtra("data"));
            }
        }
    }
}

（3）运行结果

发送广播并接收

三、发送有序广播

（1）用法介绍

• 只要将发送无序广播的sendBroadcast改为sendOrderedBroadcast就可以了
• 广播接收者在注册时声明优先级就可以了
  -可以通过abortBroadcast就可以拦截广播
  (2)代码示例

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        IntentFilter filter1=new IntentFilter();
        filter1.addAction("hello");
        filter1.setPriority(100);
        IntentFilter filter2=new IntentFilter();
        filter2.addAction("hello");
        MyBroadcastReceiver1 receiver1=new MyBroadcastReceiver1();
        MyBroadcastReceiver2 receiver2=new MyBroadcastReceiver2();
        registerReceiver(receiver1,filter1);
        registerReceiver(receiver2,filter2);
    }
    public void click(View view){
        Intent intent=new Intent("hello");
        sendOrderedBroadcast(intent,null);
    }
    class MyBroadcastReceiver1 extends BroadcastReceiver{
        public void onReceive(Context context, Intent intent){
            Log.i("test","我优先级高,我可以修改数据，可以拦截广播");
        }
    }
    class MyBroadcastReceiver2 extends BroadcastReceiver{
        public void onReceive(Context context,Intent intent){
            Log.i("test","我优先级低");
        }
    }
}

要想拦截广播

abort Broadcast();

运行结果

每次接收的广播先后顺序都一样

四、发送和接收本地广播

（1）使用介绍

之前的广播都是系统级的都可以接收到，存在安全问题，所以可以使用本地广播，首先调用LocalBroadcastManager.getInstance(this)获取LocalBroadcastManager对象，然后通过LocalBroadcastManager来registerReceiver和unRegisterReceiver，通过LocalBroadcastManager来sendBroadcast

（2）代码示例

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        LocalBroadcastManager manager=LocalBroadcastManager.getInstance(this);
        MyBroadcastReceiver receiver=new MyBroadcastReceiver();
        IntentFilter filter=new IntentFilter();
        filter.addAction("hello");
        manager.registerReceiver(receiver,filter);
    }
    public void click(View v){
        Intent intent=new Intent("hello");
        LocalBroadcastManager manager=LocalBroadcastManager.getInstance(this);
        manager.sendBroadcast(intent);
    }
    class MyBroadcastReceiver extends BroadcastReceiver{
        public void onReceive(Context context, Intent intent){
            Log.i("test","我是本地广播接收器");
        }
    }
}

五、粘性广播

（1）使用介绍

通过sendStickyBroadcast()方法发送广播，该广播发送后会一直滞留，当有匹配的接收者注册时就可以接收这条广播，发送粘性广播需要权限<uses-permission android:name="android.permission.BROADCAST_STICKY"/>
可以通过removeSticky Broadcast()移除，粘性广播只保留最后一条

（2）代码示例

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
    public void click1(View v){
        Intent intent=new Intent("hello");
        sendStickyBroadcast(intent);
    }
    public void click2(View v){
        IntentFilter filter=new IntentFilter();
        filter.addAction("hello");
        MyReceiver receiver=new MyReceiver();
        registerReceiver(receiver,filter);
    }
    class MyReceiver extends BroadcastReceiver{

        @Override
        public void onReceive(Context context, Intent intent) {
            Log.i("test","粘性广播我来接收你");
        }
    }
}