一、新建项目

二、增加权限

  <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

三、代码

public class MainActivity extends AppCompatActivity {

    private IntentFilter intentFilter;//过滤隐式意图
    private NetworkChangeReceiver networkChangeReceiver;//


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        
        intentFilter = new IntentFilter();
        intentFilter.addAction("android.net.conn.CONNECTIVITY_CHANGE");//过滤的方法
        networkChangeReceiver = new NetworkChangeReceiver();
        registerReceiver(networkChangeReceiver, intentFilter);//注册
        
    }

//取消订阅广播
    @Override
    protected void onDestroy() {
        super.onDestroy();
        unregisterReceiver(networkChangeReceiver);
    }

//新建类继承 BroadcastReceiver 重写 onReceive
    class NetworkChangeReceiver extends BroadcastReceiver {

        @Override
        public void onReceive(Context context, Intent intent) {
            ConnectivityManager connectionManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
            NetworkInfo networkInfo = connectionManager.getActiveNetworkInfo();
            if (networkInfo != null && networkInfo.isAvailable()) {
                Toast.makeText(context, "network is available", Toast.LENGTH_SHORT).show();
            } else {
                Toast.makeText(context, "network is unavailable", Toast.LENGTH_SHORT).show();
            }

        }
    }
}

四、效果

扩展 一个解决方案中多个项目（类似VS Studio）

修改文件名称

一个多个app

点击完成即可

以上，瑞思拜