未过时接口注册网络监听

整理前辈经验，自己在此做个笔记。
实现实时监听网络的变化。

import android.net.ConnectivityManager;
import android.net.Network;
import android.net.NetworkCapabilities;
import android.net.NetworkRequest;
import android.os.Bundle;
import android.util.Log;

public class MainActivity extends AppCompatActivity {
    private String TAG = "JPush";

    private ConnectivityManager connectivityManager;

    private NetworkCallbackImpl networkCallback;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main)；
        registerNetworkChange();
    }

    
    private void registerNetworkChange() {
        Object systemService = getSystemService(Context.CONNECTIVITY_SERVICE);
        if (systemService instanceof ConnectivityManager) {
            connectivityManager = (ConnectivityManager) systemService;
        }
        if (connectivityManager != null) {
            networkCallback = new NetworkCallbackImpl();
            NetworkRequest.Builder builder = new NetworkRequest.Builder();
            NetworkRequest request = builder.build();
            connectivityManager.registerNetworkCallback(request, networkCallback);
        } else {
            Log.i(TAG, "registerNetworkChange: connectivityManager is null");
        }
    }
  
    @Override
    protected void onDestroy() {
        super.onDestroy();
        if (connectivityManager != null && networkCallback != null) {
            connectivityManager.unregisterNetworkCallback(networkCallback);
        }
    }

    // 网络变化回调方式
    private class NetworkCallbackImpl extends ConnectivityManager.NetworkCallback {
        private String TAG = "JPush";

        @Override
        public void onAvailable(@NonNull Network network) {
            super.onAvailable(network);

            // 有网回调这里，如果手机没有联网，这里不回调
            Log.i(TAG, "onAvailable: 网络已连接");
        }

        @Override
        public void onLost(@NonNull Network network) {
            super.onLost(network);

            // 切换网络后，也会回调这里。如果后面再次获得网络，会回调 onCapabilitiesChanged()
            Log.i(TAG, "onLost: 网络已断开");
        }

        @Override
        public void onCapabilitiesChanged(@NonNull Network network, @NonNull NetworkCapabilities networkCapabilities) {
            super.onCapabilitiesChanged(network, networkCapabilities);
            if (networkCapabilities.hasCapability(NetworkCapabilities.NET_CAPABILITY_VALIDATED)) {
                // 再次获得网络，回调这里，所以这里可以处理继续播放视频等
                if (networkCapabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI)) {
                    Log.i(TAG, "onCapabilitiesChanged: 当前网络类型为 WiFi");
                } else if (networkCapabilities.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR)) {
                    Log.i(TAG, "onCapabilitiesChanged: 当前网络为蜂窝网络，即手机流量");
                } else {
                    Log.i(TAG, "onCapabilitiesChanged: 其他网络");
                }
            }
        }
    }
}