我写了以下代码,如果互联网连接为是,textView
对象会显示连接,如果没有则显示断开连接
但是下面的代码不能正常工作。 Null 值是问题的原因吗?
public class MainActivity extends Activity {
EditText editText;
NetworkInfo networkInfo;
String string;
ConnectivityManager connectivityManager = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
editText = (EditText) findViewById(R.id.textView);
networkInfo = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
if(networkInfo.isConnected())
editText.setText("Connect");
else if(!networkInfo.isConnected())
editText.setText("Disconnect");
}
答案 0 :(得分:0)
在您的代码中,connectivityManager为null。试试这个。
connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
boolean isConnected = activeNetworkInfo != null && activeNetworkInfo.isConnected();