Android 如何关闭选项卡中的“警报”或“进度”对话框，并阻止访问开始的选项卡？

我有一个选项卡式活动，有3个选项卡。其主要活动如下：

public class TabbedActivity2 extends AppCompatActivity {
    private ViewPager mViewPager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_tabbed2);

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setTitle("Vocabulary Paractices");
        setSupportActionBar(toolbar);
        mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
        mViewPager = (ViewPager) findViewById(R.id.container);
        mViewPager.setAdapter(mSectionsPagerAdapter);
        TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
        tabLayout.setupWithViewPager(mViewPager);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu_tabbed_activity2, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();
            if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    public static class PlaceholderFragment extends Fragment {
        private static final String ARG_SECTION_NUMBER = "section_number";

        public PlaceholderFragment() {
        }

        public static PlaceholderFragment newInstance(int sectionNumber) {
            PlaceholderFragment fragment = new PlaceholderFragment();
            Bundle args = new Bundle();
            args.putInt(ARG_SECTION_NUMBER, sectionNumber);
            fragment.setArguments(args);
            return fragment;
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
            if(getArguments().getInt(ARG_SECTION_NUMBER)==1)
            {
                View rootView = inflater.inflate(R.layout.fragment_level1fragment, container, false);
                return rootView;
            }
            else if (getArguments().getInt(ARG_SECTION_NUMBER)==2)
            {
                View rootView = inflater.inflate(R.layout.fragment_level2fragment, container, false);
                return rootView;
            }
            else
            {
                View rootView = inflater.inflate(R.layout.fragment_level3fragment, container, false);
                return rootView;
            } 
        }
    }

    public class SectionsPagerAdapter extends FragmentPagerAdapter {    
        public SectionsPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            switch (position) {
                case 0:
                    level1fragment tab1= new level1fragment();
                    return tab1;
                case 1:
                    level2fragment tab2= new level2fragment();
                    return tab2;
                case 2:
                    level3fragment tab3= new level3fragment();
                    return tab3;
                default:
                    return null;

            }
        }

        @Override
        public int getCount() {
            return 3;
        }

        @Override
        public CharSequence getPageTitle(int position) {
            switch (position) {
                case 0:
                    return "Level 1";
                case 1:
                    return "Level 2";
                case 2:
                    return "Level 3";
                default:
                    return null;

            }
        }
    }
}

片段之一：

    public class level1fragment extends Fragment {
    private Random randomGenerator;
    private TextView translation;
    private TextView idofcaps;
    private EditText useranswer;
    private CheckBox checkbox;
    private ImageView caps,nocheckbox;
    private Button controlanswer;
    private DatabaseReference myDatabase;
    private FirebaseAuth mAut;

    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";
    private String mParam1;
    private String mParam2;

    private OnFragmentInteractionListener mListener;

    public level1fragment() {
    }

    public static level1fragment newInstance(String param1, String param2) {
        level1fragment fragment = new level1fragment();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, final ViewGroup container,
                             Bundle savedInstanceState) {

        View view=inflater.inflate(R.layout.fragment_level1fragment, container, false);
        mAut= FirebaseAuth.getInstance();
        caps=(ImageView)view.findViewById(R.id.capslevel1);
        translation=(TextView)view.findViewById(R.id.translationlevel1);
        idofcaps=(TextView)view.findViewById(R.id.idofcapslevel1);
        useranswer=(EditText)view.findViewById(R.id.useranswerlevel1);
        controlanswer=(Button)view.findViewById(R.id.controlbuttonlevel1);
        nocheckbox=(ImageView)view.findViewById(R.id.nocheckboxlevel1);

        String user_id = mAut.getCurrentUser().getUid();
        myDatabase= FirebaseDatabase.getInstance().getReference();
        final DatabaseReference current_user_db = myDatabase.child("Users").child(user_id);
        final DatabaseReference myDataSelect = myDatabase.child("Caps").child("Level 1").child("Questions");
        final ProgressDialog myProgress = ProgressDialog.show(getActivity(),"Wait","Test is preparing",true);
        myDataSelect.addValueEventListener(new ValueEventListener() {

            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                final List<String> lstd = new ArrayList<String>(); // Result will be holded Here

                for (DataSnapshot ds : dataSnapshot.getChildren()) {

                    lstd.add(String.valueOf(ds.getKey()));
                    DatabaseReference solved= current_user_db.child("Caps").child("Level 1").child("Solved");

                    solved.addValueEventListener(new ValueEventListener()
                    {
                        @Override
                        public void onDataChange(DataSnapshot dataSnapshot) {
                            final List<String> solved = new ArrayList<String>(); 
                            for (DataSnapshot ds : dataSnapshot.getChildren()) {

                                solved.add(String.valueOf(ds.getValue()));

                                lstd.removeAll(solved);
                                if (lstd.isEmpty()) {
                                    ViewPager contain= (ViewPager)getActivity().findViewById(R.id.container);
                                    contain.setCurrentItem(1);
                                }

        else {
      randomGenerator = new Random();
      int index = randomGenerator.nextInt(lstd.size());
      String item = lstd.get(index);
      idofcaps.setText(item);
     final DatabaseReference capsSelect = myDataSelect.child(item);
       capsSelect.addValueEventListener(new ValueEventListener() {
         @Override
       public void onDataChange(DataSnapshot dss) {
String post_Image = (String) dss.child("Image").getValue();                                  Picasso.with(getActivity()).load(post_Image).into(caps);
String translation_caps = (String) dss.child("Translation").getValue();
translation.setText(translation_caps);
}
       @Override
    public void onCancelled(DatabaseError databaseError) {
                                        }
                                    });
                                }
                            }
                        }
       @Override
   public void onCancelled(DatabaseError databaseError) {
                        }
                    });
                    myProgress.dismiss();

                }}
            @Override
            public void onCancelled(DatabaseError databaseError) {

            }

        });

        controlanswer.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String ua= useranswer.getText().toString().trim();
                String aa= translation.getText().toString();

                if (ua.equalsIgnoreCase(aa)) {

                    useranswer.setText("");
                    String b=idofcaps.getText().toString();
                    final DatabaseReference solved = current_user_db.child("Caps").child("Level 1").child("Solved").push();
                    solved.setValue(b);

                    myDataSelect.addValueEventListener(new ValueEventListener() {
                        @Override
                        public void onDataChange(DataSnapshot dataSnapshot) {
                            final List<String> lst = new ArrayList<String>(); 
                            for (DataSnapshot ds : dataSnapshot.getChildren()) {

                                lst.add(String.valueOf(ds.getKey()));
                                solved.addValueEventListener(new ValueEventListener() {
                                    @Override
                                    public void onDataChange(DataSnapshot dataSnapshot) {
                                        final List<String> solved = new ArrayList<String>(); 
                                        for (DataSnapshot ds : dataSnapshot.getChildren()) {

                                            solved.add(String.valueOf(ds.getValue()));
                                            lst.removeAll(solved);
                                            if(lst.isEmpty())
                                            {

                                            }

 else {
      randomGenerator = new Random();
      int index = randomGenerator.nextInt(lst.size());
      String item = lst.get(index);
      idofcaps.setText(item);

  final DatabaseReference capsSelect = myDataSelect.child(item);
                                               capsSelect.addValueEventListener(new ValueEventListener() {
                                                    @Override
                                                    public void onDataChange(DataSnapshot dss) {

                                                        String post_Image = (String) dss.child("Image").getValue();
                                                        Picasso.with(getActivity()).load(post_Image).into(caps);
                                                        String post_name = (String) dss.child("Translation").getValue();
                                                        translation.setText(post_name);
                                                    }

                                                    @Override
                                                    public void onCancelled(DatabaseError databaseError) {
                                                    }
                                                });

                                            }
                                        }
                                    }
                                    @Override
                                    public void onCancelled(DatabaseError databaseError) {
                                    }
                                });
                            }
                        }

                        @Override
                        public void onCancelled(DatabaseError databaseError) {

                        }
                    });
                    nocheckbox.setVisibility(View.INVISIBLE);

                }
                else
                {
                    nocheckbox.setVisibility(View.VISIBLE);
                }
            }
        });
        return view;
    }
    public void onButtonPressed(Uri uri) {
        if (mListener != null) {
            mListener.onFragmentInteraction(uri);
        }
    }

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);

    }

    @Override
    public void onDetach() {
        super.onDetach();
        mListener = null;
    }

    public interface OnFragmentInteractionListener {
        void onFragmentInteraction(Uri uri);
    }
}

---

不过，警报对话框不会取消显示。传递tab2是可以的，但屏幕上的对话框永远不会关闭。我试过吐司留言。它也有同样的问题。信息显示大约十次，然后消失。即使我关闭手机屏幕上的应用程序，消息也不会关闭。我错在哪里？除此之外，即使是tab1和tab2问题都已完成，此toast消息或警报对话框也将从tab1开始，然后显示在tab2中。我怎么能让它们只出现一次？我的意思是当用户点击其中一个按钮时，它再也不会出现。此外，进度对话框也从不关闭。除此之外，在一些滑动之后，工具栏将显示。我不明白为什么以及如何预防它。

在另一个问题中问firebase问题。好的。我已编辑。您在代码中的何处使用了

AlertBuilder

？我在您的活动或片段中没有看到它。if（lst.isEmpty（））{in here}。我把它写空了，因为我在同一个地方试过吐司留言。我在课文中提到了这一点。

    final AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
                         builder.setTitle("Congratulations!");
                         builder.setMessage("You finished Level 1. Do you want to start Level 2?");
           builder.setNegativeButton("Not now", new DialogInterface.OnClickListener(){
                       public void onClick(DialogInterface dialog, int id) {
                                        }
                                    });

           builder.setPositiveButton("Yes", new DialogInterface.OnClickListener()
                                    {
                  public void onClick(DialogInterface dialog, int id)
                                        {
ViewPager contain= (ViewPager)getActivity().findViewById(R.id.container);
                                    contain.setCurrentItem(1);
dialog.dissmiss();
                                        }

                                    });