How to handle auto disappear a dialog fragment when internet available?

Question

I'm checking net connection, when internet is not available a custom dialog will appear and when net available again then it will disappear automatically, but when app is started and net is available already then it cause app crashing. how to fix it?

public class LoginActivity extends AppCompatActivity implements DroidListener{


        private DroidNet mDroidNet;
        MyDialog myDialog;

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

        mDroidNet = DroidNet.getInstance();
        mDroidNet.addInternetConnectivityListener(this);

        //My custom dialog
        myDialog = new MyDialog();

        }

        @Override
        public void onInternetConnectivityChanged(boolean isConnected) {
        if (isConnected) {

            myDialog.dismiss();
        } else {

            myDialog.show(getSupportFragmentManager(), "my_dialog");
            tv_check_connection.setText(R.string.no_connection);
            tv_check_connection.setVisibility(View.VISIBLE);
            connection.startAnimation(slideDownToUp);
            connection.setBackgroundColor(Color.parseColor("#2D2D2D"));
            tv_check_connection.setTextColor(Color.WHITE);

        }
    }

}

Here is my Dialog Fragment Class

public class MyDialog extends DialogFragment {

    @NonNull
    @Override
    public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
        Dialog dialog = new Dialog(getActivity(),R.style.myDialog);
        final View view = getActivity().getLayoutInflater().inflate(R.layout.custom_dialog_nointernet, null);

        dialog.getWindow().setContentView(view);
        //dialog.getWindow().setBackgroundDrawable(d);
        dialog.getWindow().setBackgroundDrawableResource(R.drawable.linearl_ayout_rounded_corner);

        final WindowManager.LayoutParams params = dialog.getWindow().getAttributes();
        params.width = WindowManager.LayoutParams.WRAP_CONTENT;
        params.height = WindowManager.LayoutParams.WRAP_CONTENT;
        params.gravity = Gravity.CENTER;

        dialog.setCanceledOnTouchOutside(true);

        Button okay = (Button) view.findViewById(R.id.buttonOkay);
        okay.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                dismiss();
            }
        });

        return dialog;

    }

}

Exception that I'm getting:

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.ritecare, PID: 2546
    java.lang.IllegalStateException: Fragment MyDialog{51034a9 (967dd225-591f-4fb0-8a7d-a15846c04836)} not associated with a fragment manager.
        at androidx.fragment.app.Fragment.requireFragmentManager(Fragment.java:910)
        at androidx.fragment.app.DialogFragment.dismissInternal(DialogFragment.java:245)
        at androidx.fragment.app.DialogFragment.dismiss(DialogFragment.java:202)
        at com.example.ritecare.activities.LoginActivity.onInternetConnectivityChanged(LoginActivity.java:292)
        at com.droidnet.DroidNet.publishInternetAvailabilityStatus(DroidNet.java:227)
        at com.droidnet.DroidNet.access$100(DroidNet.java:34)
        at com.droidnet.DroidNet$1.onTaskFinished(DroidNet.java:197)
        at com.droidnet.DroidNet$1.onTaskFinished(DroidNet.java:193)
        at com.droidnet.CheckInternetTask.onPostExecute(CheckInternetTask.java:76)
        at com.droidnet.CheckInternetTask.onPostExecute(CheckInternetTask.java:33)
        at android.os.AsyncTask.finish(AsyncTask.java:755)
        at android.os.AsyncTask.access$900(AsyncTask.java:192)
        at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:772)
        at android.os.Handler.dispatchMessage(Handler.java:107)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7356)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)

Answer 1

Put this check before you are dismissing your dialog.

   if (isConnected) {
      if (myDialog != null && myDialog.isShowing()) {
         myDialog.dismiss();   
        }
    } else {
            // other code
      myDialog.show(getSupportFragmentManager(), "my_dialog");
      tv_check_connection.setText(R.string.no_connection);
      tv_check_connection.setVisibility(View.VISIBLE);
      connection.startAnimation(slideDownToUp);
      connection.setBackgroundColor(Color.parseColor("#2D2D2D"));
      tv_check_connection.setTextColor(Color.WHITE);
    }

isShowing() method tells us Whether the dialog is currently showing or not . We are putting the check to dismiss the dialog only in the case when dialog is visible.

Answer 2

I ended up with this solution: (if you are using DialogFragment)

@Override
public void onInternetConnectivityChanged(boolean isConnected) {
    if (isConnected) {

        if (myDialog != null && myDialog.isAdded())
        {
            myDialog.dismiss();
        }
    } else {

        myDialog.show(getSupportFragmentManager(), "my_dialog");
        tv_check_connection.setText(R.string.no_connection);
        tv_check_connection.setVisibility(View.VISIBLE);
        connection.startAnimation(slideDownToUp);
        connection.setBackgroundColor(Color.parseColor("#2D2D2D"));
        tv_check_connection.setTextColor(Color.WHITE);

    }
}