列表視圖列表與onPostExecute

Question

我正在與Jsoup和aSyncTask的應用程序工作。我想在列表視圖中獲取一個html表格，但我在列表視圖中獲取數據時遇到問題。我知道我應該使用onPostExecute方法。錯誤是該方法沒有被調用，所以你應該使用@Override所以方法將被調用，但然後我有問題調用列表視圖和列表視圖中設置列表。

如果有人有其他解決方案，也將不勝感激。

這是我的代碼：

public class Cluka2 extends AsyncTask<Void, Void, String> { 

    Document document = null; 
    public List<String> list = new ArrayList<>(); 
    ListView listView = null; 
    Context context = null; 


    public Cluka2(ArrayList<String> list,Context mContext) { 
     this.list = list; 
     this.context= mContext; 
    } 

    public List<String> getList() { 
     return list; 
    } 

    public void setList(List<String> list) { 
     this.list = list; 
    } 

    @Override 
    protected String doInBackground(Void... params) { 

     try { 
      document = Jsoup.connect("https://tennisnaarden.planmysport.com/portal/page/pmsportal30/TVNaarden/Toernooien/Clubtoernooi").get(); 

      Elements elements = document.select("#pcnt1383_8158836_1383_4326089_4326089 td:first-child"); 

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

       list.add(elements.get(i).text()); 
      } 

     } catch (IOException e) { 
      e.printStackTrace(); 
     } 
     return list.toString(); 
    } 

    @Override 
    protected void onPostExecute(String result) { 
     ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(context, android.R.layout.simple_list_item_1, list); 
     Toernooien.setAdapter(arrayAdapter); 
    } 

} 

這段代碼有應用程序運行時沒有錯誤，但它並不顯示具有數據列表。

這是我的活動類：

public class ClubkampioenschappenSingleenDubbel extends AppCompatActivity { 

    ArrayList<String> list = new ArrayList<>(); 
    Context context; 
    Document doc = null; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_clubkampioenschappen_singleen_dubbel); 
     this.setTitle("Clubkampioenschappen Single en Dubbel"); 

     new Cluka2(list, context).execute(); 

     ListView Toernooien = (ListView) findViewById(R.id.Toernooien); 
    } 


    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.menu_clubkampioenschappen_singleen_dubbel, menu); 
     return true; 
    } 

    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     // Handle action bar item clicks here. The action bar will 
     // automatically handle clicks on the Home/Up button, so long 
     // as you specify a parent activity in AndroidManifest.xml. 
     int id = item.getItemId(); 

     //noinspection SimplifiableIfStatement 
     if (id == R.id.action_settings) { 
      return true; 
     } 

     return super.onOptionsItemSelected(item); 
    } 
} 

Answer 1

您已經在doInBackground()所以，你可以只是路過結果字符串作爲「成功」或「失敗」，建立您的清單。並根據您可以在您的onPostExecute()

做好相關代碼，根據您的AsynsTask的結構你onPostExecute()方法應該看起來象下面這樣：

@override 
protected void onPostExecute(String result) { 
      ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(context, android.R.layout.simple_list_item_1, list); 
      Onderdelen.setAdapter(arrayAdapter); 
     } 

除此之外，你將不得不開始您的上下文以及構造函數中。你

public Cluka2(ArrayList<String> list,Context mContext) { 
     this.list = list; 
     this.context=mContext; 
    } 

還需要將您的活動的onCreate() intiate您Listview。因此，從onPostExecute()中刪除此行並將其放入onCreate()。

ListView Onderdelen = (ListView) listView.findViewById(R.id.Toernooien); 

編輯：

您活動的onCreate（）內：

變化

new Cluka2(list, context).execute(); 

     ListView Toernooien = (ListView) findViewById(R.id.Toernooien); 

要

ListView Toernooien = (ListView) findViewById(R.id.Toernooien); 
new Cluka2(list, ClubkampioenschappenSingleenDubbel.this).execute(); 

Answer 2

問題是你的AsyncTask的結果是String，但是在你的onPostExecute方法中你期望一個List。這是正確的代碼

public class Cluka2 extends AsyncTask<Void, Void, List<String>> { 

Document document = null; 
public List<String> list = new ArrayList<>(); 
ListView listView = null; 
Context context = null; 


public Cluka2(ArrayList<String> list) { 
    this.list = list; 
} 

public List<String> getList() { 
    return list; 
} 

public void setList(List<String> list) { 
    this.list = list; 
} 

@Override 
protected List<String> doInBackground(Void... params) { 

    try { 
     document = Jsoup.connect("https://tennisnaarden.planmysport.com/portal/page/pmsportal30/TVNaarden/Toernooien/Clubtoernooi").get(); 

     Elements elements = document.select("#pcnt1383_8158836_1383_4326089_4326089 td:first-child"); 

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

      list.add(elements.get(i).text()); 
     } 

    } catch (IOException e) { 
     e.printStackTrace(); 
    } 
    return list; 
} 


protected void onPostExecute(List<String> list) { 
    ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(context, android.R.layout.simple_list_item_1, list); 
    ListView Onderdelen = (ListView) listView.findViewById(R.id.Toernooien); 
    Onderdelen.setAdapter(arrayAdapter); 
} 

}