接收音量变化的广播信号

[android]代码库

1.新建一个类extends BroadcastReceiver,并重写父类的onReceive()方法
3.在onCreat()方法中创建一个IntentFilter的实例,注册要接收的广播类型

代码:


public class BroadCastTest extends AppCompatActivity {

        private  IntentFilter intentFilter;
        private NetWorkChangeReceiver networkChangeReceiver;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_broad_cast_test);
        intentFilter=new IntentFilter();
        intentFilter.addAction("android.media.VOLUME_CHANGED_ACTION");
        networkChangeReceiver=new NetWorkChangeReceiver();
        registerReceiver(networkChangeReceiver,intentFilter);
    }

//动态注册,最后一定要销毁
    @Override
    protected void onDestroy() {
        super.onDestroy();
        unregisterReceiver(networkChangeReceiver);
    }

    class NetWorkChangeReceiver extends BroadcastReceiver {
        @Override
//接收到广播后,要执行的代码
        public void onReceive(Context context, Intent intent) {
            Toast.makeText(context, "音量改变 ", Toast.LENGTH_LONG).show();
        }
    }
}