public class MainActivity extends AppCompatActivity {
    private TextView tv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv = (TextView) findViewById(R.id.tv);
        initReceiver();
    }

    /**
     * 註冊網路監聽的廣播
     */
    private void initReceiver() {
        IntentFilter timeFilter = new IntentFilter();
        timeFilter.addAction("android.net.ethernet.ETHERNET_STATE_CHANGED");
        timeFilter.addAction("android.net.ethernet.STATE_CHANGE");
        timeFilter.addAction("android.net.conn.CONNECTIVITY_CHANGE");
        timeFilter.addAction("android.net.wifi.WIFI_STATE_CHANGED");
        timeFilter.addAction("android.net.wifi.STATE_CHANGE");
        timeFilter.addAction(WifiManager.NETWORK_STATE_CHANGED_ACTION);
        registerReceiver(netReceiver, timeFilter);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        if (netReceiver != null) {
            unregisterReceiver(netReceiver);
            netReceiver = null;
        }
    }

    BroadcastReceiver netReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            if (action.equals(ConnectivityManager.CONNECTIVITY_ACTION)) {
                ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(
                        Context.CONNECTIVITY_SERVICE);
                NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
                if (networkInfo != null && networkInfo.isAvailable()) {
                    int type2 = networkInfo.getType();
                    String typeName = networkInfo.getTypeName();
                    tv.setText(type2 + "--" + typeName);

                    switch (type2) {
                        case 0://移動 網路    2G 3G 4G 都是一樣的 實測 mix2s 聯通卡
                            Log.d("Feeee", "有網路");

                            break;
                        case 1: //wifi網路
                            Log.d("Feeee", "wifi");
                            break;

                        case 9:  //網線連線
                            Log.d("Feeee", "有網路");
                            break;
                    }
                } else {// 無網路
                    Log.d("Feeee", "無網路");
                }
            }
        }
    };
}