无法在我的Android应用中显示json数据

Question

我制作了sharmuktakkhand .java文件。

public class sharmuktakkhand extends AppCompatActiyvit {

    private final List<String> devices1 = new ArrayList<>();
    private final List<String> deviceDescription1 = new ArrayList<>();
    public String[] devices;
    public String[] deviceDescription;
    public int pos;
    private ProgressDialog loading;
    private TabLayout tabLayout;
    private ViewPager viewPager;

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


        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        getData();
        viewPager = (ViewPager) findViewById(R.id.viewpager);
        setupViewPager(viewPager);

        tabLayout = (TabLayout) findViewById(R.id.tabs);
        tabLayout.setupWithViewPager(viewPager);


    }
    private void showJSON(String response) {


        try {
            JSONObject jsonObject = new JSONObject(response);
            JSONArray result = jsonObject.getJSONArray(config.JSON_ARRAY);


            for (int i = 0; i < result.length(); i++) {
                JSONObject collegeData = result.getJSONObject(i);
                devices1.add(collegeData.getString(config.KEY_NAME));
                deviceDescription1.add(collegeData.getString(config.KEY_ADDRESS));
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }


        for(int i =0;i<devices1.size();i++){

            Toast.makeText(sharmuktakkhand.this, devices1.get(i), Toast.LENGTH_LONG).show();
            devices[i] = devices1.get(i);
            deviceDescription[i] = deviceDescription1.get(i);
        }



    }

    private void getData() {
        loading = ProgressDialog.show(sharmuktakkhand.this, "Please wait...", "Fetching...", false, false);

        String url = config.DATA_URL;

        StringRequest stringRequest = new StringRequest(url, new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                loading.dismiss();

                showJSON(response);
            }
        },
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        Toast.makeText(sharmuktakkhand.this, error.getMessage().toString(), Toast.LENGTH_LONG).show();
                    }
                });

        RequestQueue requestQueue = Volley.newRequestQueue(sharmuktakkhand.this);
        requestQueue.add(stringRequest);
    }

    public class SectionsPagerAdapter extends FragmentPagerAdapter {
        private final List<Fragment> mFragmentList = new ArrayList<>();
        private final List<String> mFragmentTitleList = new ArrayList<>();

        public SectionsPagerAdapter(FragmentManager fm) {
            super(fm);

        }

        @Override
        public Fragment getItem(int position) {

            Bundle bundle = new Bundle();
            pos = position;


            bundle.putString(kavitaFragment.DevicesKey, devices[position]);
            bundle.putString(kavitaFragment.DescriptionKey, deviceDescription[position]);


            kavitaFragment deviceFragment = new kavitaFragment();
            deviceFragment.setArguments(bundle);


            return deviceFragment;
        }

        public void findposition(int posio ){

            Intent i = new Intent(android.content.Intent.ACTION_SEND);
            i.setType("text/plain");
            i.putExtra(android.content.Intent.EXTRA_SUBJECT, "My cool app");
            i.putExtra(android.content.Intent.EXTRA_TEXT, devices[posio] + deviceDescription[posio] + "\nN.D.Nimbawat\nAdvocate");

            startActivity(Intent.createChooser(i, "Share"));

            return ;
        }
        public void addFragment(Fragment fragment, String title) {
            mFragmentList.add(fragment);
            mFragmentTitleList.add(title);
        }

        @Override
        public int getCount() {

            return  devices.length;
        }


        @Override
        public CharSequence getPageTitle(int position) {
            return mFragmentTitleList.get(position);
        }


        @Override
        public void destroyItem(ViewGroup container, int position, Object object) {
            // TODO Auto-generated method stub

            FragmentManager manager = ((Fragment) object).getFragmentManager();
            FragmentTransaction trans = manager.beginTransaction();
            trans.remove((Fragment) object);
            trans.commit();

            super.destroyItem(container, position, object);
        }
    }

    private void setupViewPager(ViewPager viewPager) {
        SectionsPagerAdapter adapter = new SectionsPagerAdapter(getSupportFragmentManager());

        for(int i = 1; i<=devices.length ; i++) {
            adapter.addFragment(new kavitaFragment(), "shar muktak khand - "+ i );
        }
        viewPager.setAdapter(adapter);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        MenuItem item = menu.findItem(R.id.action_share);
        ShareActionProvider mShareActionProvider = (ShareActionProvider) MenuItemCompat.getActionProvider(item);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case android.R.id.home:
                this.finish();
                return true;

            case R.id.action_share:

                SectionsPagerAdapter mspa = new SectionsPagerAdapter(getSupportFragmentManager());
                mspa.findposition(viewPager.getCurrentItem());
                return true;
        }
        return super.onOptionsItemSelected(item);
    }



}

和config.java文件

public static final String DATA_URL = "http://m3microtech.com/getData.php";
public static final String KEY_NAME = "title";
public static final String KEY_ADDRESS = "detail";
public static final String JSON_ARRAY = "result";

我使用JSON数组获取数据并将此数据放入device1（listArray）

问题是 - 片段不能及时创建（首先使用片段包，然后使用数组）

我的应用停止而不是运行。

请帮帮我

感谢提前

Answer 1

如果您没有数据等待数据，请不要设置setupViewPager(viewPager);，然后setupViewPager(viewPager);

将setupViewPager(viewPager);移动到json的响应部分，如下所示。

private void showJSON(String response) {

    try {
        JSONObject jsonObject = new JSONObject(response);
        JSONArray result = jsonObject.getJSONArray(config.JSON_ARRAY);

        for (int i = 0; i < result.length(); i++) {
            JSONObject collegeData = result.getJSONObject(i);
            devices1.add(collegeData.getString(config.KEY_NAME));
            deviceDescription1.add(collegeData.getString(config.KEY_ADDRESS));
        }
    } catch (JSONException e) {
        e.printStackTrace();
    }

    for(int i =0;i<devices1.size();i++){

        Toast.makeText(sharmuktakkhand.this, devices1.get(i), Toast.LENGTH_LONG).show();
        devices[i] = devices1.get(i);
        deviceDescription[i] = deviceDescription1.get(i);
    }
  //  set here when your data is ready and also add check if data is null and show toast or your logic?
  setupViewPager(viewPager);
}