当互联网可用时如何处理自动消失的对话框片段？

Question

我正在检查网络连接，当无法使用互联网时，将出现一个自定义对话框，当再次可用时，它将自动消失，但是当启动应用程序且网络已经可用时，它将导致应用程序崩溃。如何解决？

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);

        }
    }

}

这是我的对话框片段类

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;

    }

}

我得到的异常：

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

在取消对话框之前，请勾选此复选框。

   if (isConnected) {
      if (myDialog != null && myDialog.isShowing()) {
         myDialog.dismiss();   
        }
    } else {
            // other code
    }

isShowing()方法告诉我们是否当前显示对话框。我们仅在对话框可见的情况下进行检查以关闭对话框。