無法在我的Android應用程序中顯示json數據

Question

我製作了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"; 

我取使用JSON陣列數據，並把這個數據在DEVICE1（listArray）

問題是 - 片段不首先創建及時（片段箱然後陣列使用）

我的應用程序停止並未運行。

請幫我

感謝提前

Answer 1

不要設置setupViewPager(viewPager);如果你沒有數據等數據，然後setupViewPager(viewPager);

移動setupViewPager(viewPager);爲以下JSON的響應部件。

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); 
}