Jak coś się świeci na czerwono, to tam zawsze wyskakuje jakiś podpowiedź, rozwiązanie. Warto to czasem przeczytać.
No ale Twoja klasa będzie wyglądała mniej więcej tak:
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
public class MainActivity extends AppCompatActivity {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final TextView text = (TextView) findViewById(R.id.ukrytyTekst);
Button manageVisibilityOfText = (Button) findViewById(R.id.guzik);
manageVisibilityOfText.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
text.setVisibility(View.VISIBLE);
ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(CONNECTIVITY_SERVICE);
NetworkInfo mobileInfo = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
String dataConnectionStatus = String.valueOf(mobileInfo.getState());
text.setText(dataConnectionStatus);
if(dataConnectionStatus == "DISCONNECTED") {
try {
setMobileDataEnabled(getApplicationContext(), true);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (NoSuchFieldException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (NoSuchMethodException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
}
}
});
}
private void setMobileDataEnabled(Context context, boolean enabled) throws ClassNotFoundException, NoSuchFieldException, IllegalAccessException, NoSuchMethodException, InvocationTargetException {
final ConnectivityManager conman = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
final Class conmanClass = Class.forName(conman.getClass().getName());
final Field connectivityManagerField = conmanClass.getDeclaredField("mService");
connectivityManagerField.setAccessible(true);
final Object connectivityManager = connectivityManagerField.get(conman);
final Class connectivityManagerClass = Class.forName(connectivityManager.getClass().getName());
final Method setMobileDataEnabledMethod = connectivityManagerClass.getDeclaredMethod("setMobileDataEnabled", Boolean.TYPE);
setMobileDataEnabledMethod.setAccessible(true);
setMobileDataEnabledMethod.invoke(connectivityManager, enabled);
}
}