空白屏幕顯示

當我點擊搜索捐助話，就說明空白屏幕列表視圖我不知道爲什麼，這是我從服務器獲取空白屏幕顯示

迴響應這是我的自定義適配器代碼：

package com.example.kamran.ebloodbank; 

import android.app.Activity; 
import android.content.Context; 
import android.support.annotation.NonNull; 
import android.support.annotation.Nullable; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.ArrayAdapter; 
import android.widget.BaseAdapter; 
import android.widget.TextView; 

import java.util.List; 

/** 
* Created by Kamran on 4/12/2017. 
*/ 

public class DonorAdapter extends BaseAdapter { 

    private Activity activity; 
    private LayoutInflater inflater; 
    private List<DataSet> donorItems; 

    public DonorAdapter(Activity activity,List<DataSet> donorItems) { 
     this.activity = activity; 
     this.donorItems = donorItems; 

    } 

    @Override 
    public int getCount() { 
     return donorItems.size(); 
    } 

    @Override 
    public Object getItem(int location) { 
     return donorItems.get(location); 
    } 

    @Override 
    public long getItemId(int position) { 
     return position; 
    } 

    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 
     if (inflater == null) 
      inflater = (LayoutInflater) activity 
        .getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
     if (convertView == null) 
      convertView = inflater.inflate(R.layout.donor_search_list_theme, null); 

     TextView nameTextView = (TextView) convertView.findViewById(R.id.donor_name); 
     TextView areaTextView = (TextView) convertView.findViewById(R.id.donor_area); 

     DataSet d = donorItems.get(position); 

     nameTextView.setText(d.getName()); 
     areaTextView.setText(d.getArea()); 
     return convertView; 
    } 
}

這是我的模型代碼：

package com.example.kamran.ebloodbank; 

import android.widget.ArrayAdapter; 

import java.util.ArrayList; 

/** 
* Created by Kamran on 4/12/2017. 
*/ 

public class DataSet { 
    private String name; 
    private int area; 


    public void setArea(int area) { 
     this.area = area; 
    } 

    public void setName(String name) { 
     this.name = name; 
    } 

    public int getArea() { 
     return area; 
    } 

    public String getName() { 
     return name; 
    } 


}

這是我的第一個活動代碼：

package com.example.kamran.ebloodbank; 

import android.content.Intent; 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.text.TextUtils; 
import android.view.View; 
import android.widget.AdapterView; 
import android.widget.ArrayAdapter; 
import android.widget.Button; 
import android.widget.ListView; 
import android.widget.Spinner; 

import com.android.volley.AuthFailureError; 
import com.android.volley.Request; 
import com.android.volley.RequestQueue; 
import com.android.volley.Response; 
import com.android.volley.VolleyError; 
import com.android.volley.toolbox.StringRequest; 
import com.android.volley.toolbox.Volley; 
import com.example.kamran.ebloodbank.data.BloodContract.BloodEntry; 

import org.json.JSONArray; 
import org.json.JSONException; 
import org.json.JSONObject; 

import java.util.ArrayList; 
import java.util.HashMap; 
import java.util.List; 
import java.util.Map; 

public class FindDonor extends AppCompatActivity { 

    Spinner bloodgroup; 
    Spinner area; 
    String findDonorUrl = "https://wwwkamranalitk.000webhostapp.com/findDonor.php"; 
    int mBlood = BloodEntry.BLOOD_GROUP_A_POS; 
    int mArea = BloodEntry.DONOR_AREA_MALIR; 
    Button searchButton; 
    RequestQueue requestQueue; 
    StringRequest request; 
    JSONObject jsonObject; 
    JSONArray result; 
    private List<DataSet> donorList = new ArrayList<DataSet>(); 

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


     bloodgroup = (Spinner) findViewById(R.id.bloodspinnerfinddonor); 
     area = (Spinner) findViewById(R.id.areaSpinner); 
     searchButton = (Button) findViewById(R.id.searchDonor); 
     setupSpinnerBlood(); 
     setupSpinnerArea(); 
     requestQueue = Volley.newRequestQueue(getApplicationContext()); 

     searchButton.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 
       request = new StringRequest(Request.Method.POST, findDonorUrl, new Response.Listener<String>() { 
        @Override 
        public void onResponse(String response) { 

          try { 
           jsonObject = new JSONObject(response); 
           result = jsonObject.getJSONArray("result"); 
           JSONObject donorData = result.getJSONObject(0); 
           DataSet donorSet = new DataSet(); 

           donorSet.setName(donorData.getString("name")); 
           donorSet.setArea(donorData.getInt("area")); 
           donorList.add(donorSet); 
           Intent intent = new Intent(FindDonor.this, DonorSearchList.class); 

           startActivity(intent); 
           finish(); 
          } catch (JSONException e) { 
           e.printStackTrace(); 
          } 

        } 
       }, new Response.ErrorListener() { 
        @Override 
        public void onErrorResponse(VolleyError error) { 

        } 
       }){ 
        @Override 
        protected Map<String, String> getParams() throws AuthFailureError { 
         HashMap<String,String> parameters = new HashMap<String, String>(); 

         parameters.put("bloodgroup", String.valueOf(mBlood)); 
         parameters.put("area", String.valueOf(mArea)); 

         return parameters; 
        } 
       }; 

       requestQueue.add(request); 
      } 
     }); 

    } 




    private void setupSpinnerBlood() { 
     ArrayAdapter bloodGroupSpinnerAdapter = ArrayAdapter.createFromResource(this, R.array.blood_group, android.R.layout.simple_spinner_item); 
     bloodGroupSpinnerAdapter.setDropDownViewResource(android.R.layout.simple_dropdown_item_1line); 
     bloodgroup.setAdapter(bloodGroupSpinnerAdapter); 

     bloodgroup.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() { 
      @Override 
      public void onItemSelected(AdapterView<?> parent, View view, int position, long id) { 
       String selection = (String) parent.getItemAtPosition(position); 
       if (!TextUtils.isEmpty(selection)) { 
        if (selection.equals(getString(R.string.blood_apos))) { 
         mBlood = BloodEntry.BLOOD_GROUP_A_POS; 
        } else if (selection.equals((getString(R.string.blood_bpos)))) { 
         mBlood = BloodEntry.BLOOD_GROUP_B_POS; 
        } else if (selection.equals(getString(R.string.blood_opos))) { 
         mBlood = BloodEntry.BLOOD_GROUP_O_POS; 
        } else if (selection.equals((getString(R.string.blood_oneg)))) { 
         mBlood = BloodEntry.BLOOD_GROUP_O_NEG; 
        } 
       } 
      } 


      @Override 
      public void onNothingSelected(AdapterView<?> adapterView) { 
       mBlood = BloodEntry.BLOOD_GROUP_A_POS; 
      } 
     }); 
    } 

    private void setupSpinnerArea() { 
     ArrayAdapter areaSpinnerAdapter = ArrayAdapter.createFromResource(this, R.array.area, android.R.layout.simple_spinner_item); 
     areaSpinnerAdapter.setDropDownViewResource(android.R.layout.simple_dropdown_item_1line); 
     area.setAdapter(areaSpinnerAdapter); 

     area.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() { 
      @Override 
      public void onItemSelected(AdapterView<?> parent, View view, int position, long id) { 
       String selection = (String) parent.getItemAtPosition(position); 
       if (!TextUtils.isEmpty(selection)) { 
        if (selection.equals(getString(R.string.donor_area_malir))) { 
         mArea = BloodEntry.DONOR_AREA_MALIR; 
        } else if (selection.equals(getString(R.string.donor_area_defence))) { 
         mArea = BloodEntry.DONOR_AREA_DEFENCE; 
        } else if (selection.equals(getString(R.string.donor_area_korangi))) { 
         mArea = BloodEntry.DONOR_AREA_KORANGI; 
        } else if (selection.equals(getString(R.string.donor_area_johar))) { 
         mArea = BloodEntry.DONOR_AREA_JOHAR; 
        } 
       } 
      } 

      @Override 
      public void onNothingSelected(AdapterView<?> adapterView) { 
       mArea = BloodEntry.DONOR_AREA_MALIR; 
      } 
     }); 

    } 


}

，這是該數據將被顯示的代碼：您需要將數據從搜索轉移到列出活動

package com.example.kamran.ebloodbank; 

import android.content.Intent; 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.ListView; 
import android.widget.TextView; 

import java.util.ArrayList; 
import java.util.HashMap; 
import java.util.List; 

public class DonorSearchList extends AppCompatActivity { 

    private String mArea; 
    private List<DataSet> donorList = new ArrayList<DataSet>(); 
    private ListView listView; 
    private DonorAdapter adapter; 

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

     listView = (ListView) findViewById(R.id.donorListView); 
     adapter = new DonorAdapter(this, donorList); 

     listView.setAdapter(adapter); 



    } 
}

來源

2017-04-12 Kamran Ali

。嘗試是這樣的：

public class bridge { 
    public static List<DataSet> donorList = new ArrayList<DataSet>(); 
}

然後，在類FindDonor：

donorSet.setName(donorData.getString("name")); 
donorSet.setArea(donorData.getInt("area")); 
donorList.add(donorSet); 
//here put this line 
bridge.donarList = donarList; 
//rest code 
Intent intent = new Intent(FindDonor.this, DonorSearchList.class);

然後，在DonorSearchList類：

adapter = new DonorAdapter(this, bridge.donorList);

來源

2017-04-12 17:12:45

空白屏幕顯示

回答

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