解决安卓Android 8.0以上的静态广播无法注册

Android 8.0以上需要setComponent()来指定包名和类名，第1个参数是指接收广播类的包名，第2个参数是指接收广播类的完整类名。
静态广播
1.先使用Android Studio创建一个广播接收类。File->New->Other->Broadcast Receiver，先创建一个广播类，这个创建的类会自动帮我们继承BroadcastReceiver类，接收广播，需要继承这个类。

• MyReceiver.java

public class MyReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        // TODO: This method is called when the BroadcastReceiver is receiving
        // an Intent broadcast.
        Toast.makeText(context, "收到广播", Toast.LENGTH_SHORT).show();
    }
}

上面的代码，很简单，就是在接收到广播时，弹出一个toast提示框。
2.发送广播
在界面上添加一个Button按钮，然后编写按钮的onclick事件。

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button btn1=findViewById(R.id.btn1);
        btn1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent("com.example.boardreceiver1.broadcast1");//这一步可以分解为下面两步
//                Intent intent=new Intent();
//                intent.setAction("com.example.boardreceiver1.broadcast1");
                intent.setComponent(new ComponentName("com.example.boardreceiver1","com.example.boardreceiver1.MyReceiver"));
// 上面这一行在Android 7.0及以下版本不是必须的，但是Android 8.0或者更高版本，发送广播的条件更加严苛，必须添加这一行内容。
// 创建的ComponentName实例化对象有两个参数，第1个参数是指接收广播类的包名，第2个参数是指接收广播类的完整类名。
               sendBroadcast(intent,null);
            }
        });
    }
}

3.运行结果

发送两个不同的广播

• MyReceiver

public class MyReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
     
       switch (intent.getAction()){
           case "广播1":
               Toast.makeText(context, "我收到了广播1", Toast.LENGTH_SHORT).show();
               break;
           case "广播2":
               Toast.makeText(context, "我收到了广播2", Toast.LENGTH_SHORT).show();
               break;
       }
    }
}

• MainActivity

public class MainActivity extends AppCompatActivity {
      @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        findViewById(R.id.send1).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent1=new Intent();
                intent1.setAction("广播1");
                intent1.setComponent(new ComponentName(getPackageName(),getPackageName()+".MyReceiver"));
                sendBroadcast(intent1);
            }
        });
        findViewById(R.id.send2).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent inten2t=new Intent();
                inten2t.setAction("广播2");
                inten2t.setComponent(new ComponentName(getPackageName(),getPackageName()+".MyReceiver"));
                sendBroadcast(inten2t);
            }
        });
    }
}

动态广播

先在Manifest文件中删除下面内容

        <receiver
            android:name=".MyStaticReceiver"
            android:enabled="true"
            android:exported="true"></receiver>

然后上图

可以看到，直接发广播是没有用的，要注册了之后才行
代码

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        findViewById(R.id.active_BC).setOnClickListener(this);
        findViewById(R.id.static_BC).setOnClickListener(this);
        findViewById(R.id.register).setOnClickListener(this);
        findViewById(R.id.unregister).setOnClickListener(this);
    }
    public MyActiveReceiver mReceiver=null;
    IntentFilter mFilter=new IntentFilter(MyActiveReceiver.ACTION);
    @Override
    public void onClick(View view) {
        switch (view.getId()){
            case R.id.static_BC:
                sendStaticBC();
                break;
            case R.id.active_BC:
                Intent i=new Intent(MyActiveReceiver.ACTION);
                sendBroadcast(i);
                break;
            case R.id.register:
                if (mReceiver==null){
                    mReceiver=new MyActiveReceiver();
                    registerReceiver(mReceiver,mFilter);
                }
                break;
            case R.id.unregister:
                if (mReceiver!=null){
                    unregisterReceiver(mReceiver);
                    mReceiver=null;
                }
                break;
        }
    }

    private void sendStaticBC() {
        Intent intent=new Intent(getPackageName());
        intent.setComponent(new ComponentName(getPackageName(),getPackageName()+".MyStaticReceiver"));
        sendBroadcast(intent);
    }
}

MyActiveReceiver

public class MyActiveReceiver extends BroadcastReceiver {
    public static final String ACTION = "xxxxxxxxxxxxxxxxx";
    @Override
    public void onReceive(Context context, Intent intent) {
        Toast.makeText(context, "我收到了动态广播", Toast.LENGTH_SHORT).show();
    }
}

下面这个为了配合第二个动态广播的静态接收广播类。

public class MyStaticReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        Toast.makeText(context, "收到了静态广播！", Toast.LENGTH_SHORT).show();
    }
}