Просматривая базу данных с помощью курсоров, что-то не хватает?

Я пытаюсь создать приложение для чтения новостей, в котором содержимое новостей извлекается из api с использованием JSON и хранится в ListView, чтобы пользователи могли видеть разные заголовки статей. Я создал 2 AsyncTask:Просматривая базу данных с помощью курсоров, что-то не хватает?

Первый из них используется для извлечения списка идентификаторов статей из Top Stories из JSONArray.I извлекает каждый отдельный идентификатор статьи, используя цикл for, который выполняется 10 раз, чтобы получить 10 идентификаторов статьи ,

Вторая AsyncTask вызывается внутри первой. Мне нужно передать другой url во второй AsyncTask, используя специальный идентификатор статьи, чтобы получить текст статьи, заголовок и ссылку, которые я хочу добавить в столбец «articleId» и «url» моей таблицы.

У меня возникла проблема с отображением содержимого таблицы. Я стремился к тому, что только после того, как все 10 строк были заполнены благодаря AsynTask, я покажу содержимое моей таблицы один раз.

Это то, что мой код выглядит сейчас:

public class MainActivity extends AppCompatActivity { 

DownloadIdList idTask; 
DownloadArticle articleTask; 
SQLiteDatabase newsReaderDB; 

ListView listView; 
ArrayList<String> articlesList = new ArrayList<String>(); 
ArrayAdapter<String> arrayAdapter; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 
    setSupportActionBar(toolbar); 

    idTask = new DownloadIdList(); 
    listView = (ListView) findViewById(R.id.listView); 
    arrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, articlesList); 
    listView.setAdapter(arrayAdapter); 

    try { 

     newsReaderDB = this.openOrCreateDatabase("News", MODE_PRIVATE, null); 

     newsReaderDB.execSQL("CREATE TABLE IF NOT EXISTS topStories (id INTEGER PRIMARY KEY, articleId INT(10), title VARCHAR, url VARCHAR)"); 

     //newsReaderDB.execSQL("DROP TABLE topStories"); 

     //Toast.makeText(getApplicationContext(),"Database deleted", Toast.LENGTH_LONG).show(); 

    } catch (Exception e) { 

     Toast.makeText(getApplicationContext(), "Can't create or open Database On Create", Toast.LENGTH_LONG).show(); 

    } 


    try { 

     idTask.execute("https://hacker-news.firebaseio.com/v0/topstories.json?print=pretty"); 

    } catch (Exception e) { 
      e.printStackTrace(); 
     Toast.makeText(getApplicationContext(),"Can't download URL", Toast.LENGTH_LONG).show(); 

    } 
} 

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

    @Override 
    protected String doInBackground(String... urls) { 

     String result = ""; 

     URL url; 

     HttpURLConnection urlConnection = null; 

     try { 

      url = new URL(urls[0]); 

      urlConnection = (HttpURLConnection) url.openConnection(); 

      InputStream inputStream = urlConnection.getInputStream(); 

      InputStreamReader reader = new InputStreamReader(inputStream); 

      int data = reader.read(); 

      while (data != -1) { 

       char current = (char) data; 

       result += current; 

       data = reader.read(); 

      } 

      return result; 

     }catch (Exception e) { 
      e.printStackTrace(); 
      Toast.makeText(getApplicationContext(),"Can't get Top Stories Id's" ,Toast.LENGTH_LONG).show(); 

     } 

     return null; 
    } 


    @Override 
    protected void onPostExecute(String result) { 
     super.onPostExecute(result); 

     try { 

      JSONArray idArray = new JSONArray(result); 

      for (int i=0; i < 10; i++) { 

       int value = idArray.getInt(i); 
       Log.i("Top Stories Id", String.valueOf(value)); 
       String id = String.valueOf(value); 

       articleTask = new DownloadArticle(); 

        try { 
         articleTask.execute("https://hacker-news.firebaseio.com/v0/item/" + id + ".json?print=pretty"); 


        } catch (Exception e) { 
         e.printStackTrace(); 
         Toast.makeText(getApplicationContext(),"can't get article info from id",Toast.LENGTH_LONG).show(); 

        } 
      } 

     }catch (JSONException e) { 
      e.printStackTrace(); 
      Toast.makeText(getApplicationContext(),"Can't get JSON Object",Toast.LENGTH_LONG).show(); 
     } 


    } 
} 

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

    @Override 
    protected String doInBackground(String... urls) { 

     String content = ""; 

     URL url; 

     HttpURLConnection urlConnection = null; 

     try { 

      url = new URL(urls[0]); 

      urlConnection = (HttpURLConnection) url.openConnection(); 

      InputStream inputStream = urlConnection.getInputStream(); 

      InputStreamReader reader = new InputStreamReader(inputStream); 

      int data = reader.read(); 

      while (data != -1) { 

       char current = (char) data; 

       content += current; 

       data = reader.read(); 

      } 

      return content; 

     } catch (Exception e) { 
      e.printStackTrace(); 
      Toast.makeText(getApplicationContext(), "Can't get Articles after retrieving the id", Toast.LENGTH_LONG).show(); 

     } 

     return null; 
    } 

    @Override 
    protected void onPostExecute(String content) { 
     super.onPostExecute(content); 

     try { 

      JSONObject jsonObject = new JSONObject(content); 

      int idInfo = jsonObject.getInt("id"); 
      String title = String.valueOf(jsonObject.getString("title")); 
      title = title.replaceAll("'","''"); 
      String urlien = String.valueOf(jsonObject.getString("url")); 


      //newsReaderDB = openOrCreateDatabase("News", MODE_PRIVATE, null); 
      newsReaderDB.execSQL("INSERT INTO topStories (articleId, title, url) VALUES(" + idInfo + ", '" + title + "','" + urlien + "');"); 
      showData(); 


     }catch (JSONException e) { 
      e.printStackTrace(); 
      Toast.makeText(getApplicationContext(), "Can't get Article", Toast.LENGTH_LONG).show(); 

     } 
    } 
} 

/*public void showDatabase() { 

    try { 

     newsReaderDB = this.openOrCreateDatabase("News", MODE_PRIVATE, null); 

     Cursor c = newsReaderDB.rawQuery("SELECT * FROM topStories", null); 

     c.moveToFirst(); 

     int idIndex = c.getColumnIndex("id"); 

     int a_idIndex = c.getColumnIndex("articleId"); 

     int titleIndex = c.getColumnIndex("title"); 

     int urlIndex = c.getColumnIndex("url"); 

     c.moveToFirst(); 

     while (c != null) { 

      Log.i("Id", String.valueOf(c.getInt(idIndex))); 
      Log.i("Article id", String.valueOf(c.getInt(a_idIndex))); 
      Log.i("Title", c.getString(titleIndex)); 
      Log.i("Url Link", c.getString(urlIndex)); 

      c.moveToNext(); 
     } 

    } catch (Exception e) { 
     e.printStackTrace(); 
     Toast.makeText(getApplicationContext(), "Unable to List Database", Toast.LENGTH_LONG).show(); 
    } 
}*/ 

public void showData() { 
try { 
    Cursor cursor = newsReaderDB.rawQuery("SELECT * FROM topStories", null); 
    if (cursor.moveToFirst()) { 
     do { 
      String id = String.valueOf(cursor.getInt(cursor.getColumnIndex("id"))); 
      String a_id = String.valueOf(cursor.getInt(cursor.getColumnIndex("articleId"))); 
      String title = cursor.getString(cursor.getColumnIndex("title")); 
      String url = cursor.getString(cursor.getColumnIndex("url")); 

      Log.i("id", id); 
      Log.i("article id", a_id); 
      Log.i("title", title); 
      Log.i("url", url); 
     } while (cursor.moveToNext()); 
    } cursor.close(); 
}catch (Exception e) { 

    e.printStackTrace(); 
} 

} 

@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_main, 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); 
} 

}

Выход:

10-15 12:23:42.755 32635-32635/com.iboundiaye.newsreader I/Top Stories Id: 12713089 
    10-15 12:23:42.756 32635-32635/com.iboundiaye.newsreader I/Top Stories Id: 12713249 
    10-15 12:23:42.756 32635-32635/com.iboundiaye.newsreader I/Top Stories Id: 12711343 
    10-15 12:23:42.756 32635-32635/com.iboundiaye.newsreader I/Top Stories Id: 12711511 
    10-15 12:23:42.757 32635-32635/com.iboundiaye.newsreader I/Top Stories Id: 12713056 
    10-15 12:23:42.757 32635-32635/com.iboundiaye.newsreader I/Top Stories Id: 12709220 
    10-15 12:23:42.757 32635-32635/com.iboundiaye.newsreader I/Top Stories Id: 12707606 
    10-15 12:23:42.757 32635-32635/com.iboundiaye.newsreader I/Top Stories Id: 12712577 
    10-15 12:23:42.757 32635-32635/com.iboundiaye.newsreader I/Top Stories Id: 12709820 
    10-15 12:23:42.757 32635-32635/com.iboundiaye.newsreader I/Top Stories Id: 12712454 
    10-15 12:23:43.013 32635-32635/com.iboundiaye.newsreader I/id: 1 
    10-15 12:23:43.013 32635-32635/com.iboundiaye.newsreader I/article id: 12713089 
    10-15 12:23:43.013 32635-32635/com.iboundiaye.newsreader I/title: KiCad: A commitment to freedom 
    10-15 12:23:43.013 32635-32635/com.iboundiaye.newsreader I/url: https://giving.web.cern.ch/content/kicad-development-1 
    10-15 12:23:43.259 32635-32635/com.iboundiaye.newsreader I/id: 1 
    10-15 12:23:43.259 32635-32635/com.iboundiaye.newsreader I/article id: 12713089 
    10-15 12:23:43.259 32635-32635/com.iboundiaye.newsreader I/title: KiCad: A commitment to freedom 
    10-15 12:23:43.259 32635-32635/com.iboundiaye.newsreader I/url: https://giving.web.cern.ch/content/kicad-development-1 
    10-15 12:23:43.259 32635-32635/com.iboundiaye.newsreader I/id: 2 
    10-15 12:23:43.259 32635-32635/com.iboundiaye.newsreader I/article id: 12713249 
    10-15 12:23:43.259 32635-32635/com.iboundiaye.newsreader I/title: What has happened down here is the winds have changed 
    10-15 12:23:43.259 32635-32635/com.iboundiaye.newsreader I/url: http://andrewgelman.com/2016/09/21/what-has-happened-down-here-is-the-winds-have-changed/ 
    10-15 12:23:43.467 32635-32635/com.iboundiaye.newsreader I/id: 1 
    10-15 12:23:43.467 32635-32635/com.iboundiaye.newsreader I/article id: 12713089 
    10-15 12:23:43.467 32635-32635/com.iboundiaye.newsreader I/title: KiCad: A commitment to freedom 
    10-15 12:23:43.467 32635-32635/com.iboundiaye.newsreader I/url: https://giving.web.cern.ch/content/kicad-development-1 
    10-15 12:23:43.467 32635-32635/com.iboundiaye.newsreader I/id: 2 
    10-15 12:23:43.467 32635-32635/com.iboundiaye.newsreader I/article id: 12713249 
    10-15 12:23:43.467 32635-32635/com.iboundiaye.newsreader I/title: What has happened down here is the winds have changed 
    10-15 12:23:43.467 32635-32635/com.iboundiaye.newsreader I/url: http://andrewgelman.com/2016/09/21/what-has-happened-down-here-is-the-winds-have-changed/ 
    10-15 12:23:43.467 32635-32635/com.iboundiaye.newsreader I/id: 3 
    10-15 12:23:43.467 32635-32635/com.iboundiaye.newsreader I/article id: 12711343 
    10-15 12:23:43.467 32635-32635/com.iboundiaye.newsreader I/title: A single byte write opened a root execution exploit 
    10-15 12:23:43.467 32635-32635/com.iboundiaye.newsreader I/url: https://daniel.haxx.se/blog/2016/10/14/a-single-byte-write-opened-a-root-execution-exploit/ 
    10-15 12:23:43.722 32635-32635/com.iboundiaye.newsreader I/id: 1 
    10-15 12:23:43.722 32635-32635/com.iboundiaye.newsreader I/article id: 12713089 
    10-15 12:23:43.722 32635-32635/com.iboundiaye.newsreader I/title: KiCad: A commitment to freedom 
    10-15 12:23:43.722 32635-32635/com.iboundiaye.newsreader I/url: https://giving.web.cern.ch/content/kicad-development-1 
    10-15 12:23:43.722 32635-32635/com.iboundiaye.newsreader I/id: 2 
    10-15 12:23:43.722 32635-32635/com.iboundiaye.newsreader I/article id: 12713249 
    10-15 12:23:43.722 32635-32635/com.iboundiaye.newsreader I/title: What has happened down here is the winds have changed 
    10-15 12:23:43.722 32635-32635/com.iboundiaye.newsreader I/url: http://andrewgelman.com/2016/09/21/what-has-happened-down-here-is-the-winds-have-changed/ 
    10-15 12:23:43.722 32635-32635/com.iboundiaye.newsreader I/id: 3 
    10-15 12:23:43.722 32635-32635/com.iboundiaye.newsreader I/article id: 12711343 
    10-15 12:23:43.722 32635-32635/com.iboundiaye.newsreader I/title: A single byte write opened a root execution exploit 
    10-15 12:23:43.723 32635-32635/com.iboundiaye.newsreader I/url: https://daniel.haxx.se/blog/2016/10/14/a-single-byte-write-opened-a-root-execution-exploit/ 
    10-15 12:23:43.723 32635-32635/com.iboundiaye.newsreader I/id: 4 
    10-15 12:23:43.723 32635-32635/com.iboundiaye.newsreader I/article id: 12711511 
    10-15 12:23:43.723 32635-32635/com.iboundiaye.newsreader I/title: Books Programmers Don't Really Read (2008) 
    10-15 12:23:43.723 32635-32635/com.iboundiaye.newsreader I/url: http://www.billthelizard.com/2008/12/books-programmers-dont-really-read.html 
    10-15 12:23:43.909 32635-32635/com.iboundiaye.newsreader W/System.err: org.json.JSONException: No value for url 
    10-15 12:23:43.910 32635-32635/com.iboundiaye.newsreader W/System.err:  at org.json.JSONObject.get(JSONObject.java:389) 
    10-15 12:23:43.910 32635-32635/com.iboundiaye.newsreader W/System.err:  at org.json.JSONObject.getString(JSONObject.java:550) 
    10-15 12:23:43.910 32635-32635/com.iboundiaye.newsreader W/System.err:  at com.iboundiaye.newsreader.MainActivity$DownloadArticle.onPostExecute(MainActivity.java:216) 
    10-15 12:23:43.910 32635-32635/com.iboundiaye.newsreader W/System.err:  at com.iboundiaye.newsreader.MainActivity$DownloadArticle.onPostExecute(MainActivity.java:161) 
    10-15 12:23:43.910 32635-32635/com.iboundiaye.newsreader W/System.err:  at android.os.AsyncTask.finish(AsyncTask.java:632) 
    10-15 12:23:43.910 32635-32635/com.iboundiaye.newsreader W/System.err:  at android.os.AsyncTask.access$600(AsyncTask.java:177) 
    10-15 12:23:43.910 32635-32635/com.iboundiaye.newsreader W/System.err:  at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:645) 
    10-15 12:23:43.910 32635-32635/com.iboundiaye.newsreader W/System.err:  at android.os.Handler.dispatchMessage(Handler.java:102) 
    10-15 12:23:43.910 32635-32635/com.iboundiaye.newsreader W/System.err:  at android.os.Looper.loop(Looper.java:135) 
    10-15 12:23:43.910 32635-32635/com.iboundiaye.newsreader W/System.err:  at android.app.ActivityThread.main(ActivityThread.java:5221) 
    10-15 12:23:43.910 32635-32635/com.iboundiaye.newsreader W/System.err:  at java.lang.reflect.Method.invoke(Native Method) 
    10-15 12:23:43.910 32635-32635/com.iboundiaye.newsreader W/System.err:  at java.lang.reflect.Method.invoke(Method.java:372) 
    10-15 12:23:43.914 32635-32635/com.iboundiaye.newsreader W/System.err:  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899) 
    10-15 12:23:43.914 32635-32635/com.iboundiaye.newsreader W/System.err:  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)

, а затем он продолжает давать набор увеличенными данных до статьи 9. На этом этапе должен дать до статьи 10, но по какой-то причине он считает его нулевым, поэтому он пропускает один комплект и показывает до тех пор, пока не будет приведена статья 9.

Мой желаемый результат:

10-15 12:23:42.755 32635-32635/com.iboundiaye.newsreader I/Top Stories Id: 12713089 
10-15 12:23:42.756 32635-32635/com.iboundiaye.newsreader I/Top Stories Id: 12713249 
10-15 12:23:42.756 32635-32635/com.iboundiaye.newsreader I/Top Stories Id: 12711343 
10-15 12:23:42.756 32635-32635/com.iboundiaye.newsreader I/Top Stories Id: 12711511 
10-15 12:23:42.757 32635-32635/com.iboundiaye.newsreader I/Top Stories Id: 12713056 
10-15 12:23:42.757 32635-32635/com.iboundiaye.newsreader I/Top Stories Id: 12709220 
10-15 12:23:42.757 32635-32635/com.iboundiaye.newsreader I/Top Stories Id: 12707606 
10-15 12:23:42.757 32635-32635/com.iboundiaye.newsreader I/Top Stories Id: 12712577 
10-15 12:23:42.757 32635-32635/com.iboundiaye.newsreader I/Top Stories Id: 12709820 
10-15 12:23:42.757 32635-32635/com.iboundiaye.newsreader I/Top Stories Id: 12712454 
    10-15 12:23:45.109 32635-32635/com.iboundiaye.newsreader I/id: 1 
    10-15 12:23:45.109 32635-32635/com.iboundiaye.newsreader I/article id: 12713089 
    10-15 12:23:45.109 32635-32635/com.iboundiaye.newsreader I/title: KiCad: A commitment to freedom 
    10-15 12:23:45.109 32635-32635/com.iboundiaye.newsreader I/url: https://giving.web.cern.ch/content/kicad-development-1 
    10-15 12:23:45.109 32635-32635/com.iboundiaye.newsreader I/id: 2 
    10-15 12:23:45.109 32635-32635/com.iboundiaye.newsreader I/article id: 12713249 
    10-15 12:23:45.109 32635-32635/com.iboundiaye.newsreader I/title: What has happened down here is the winds have changed 
    10-15 12:23:45.109 32635-32635/com.iboundiaye.newsreader I/url: http://andrewgelman.com/2016/09/21/what-has-happened-down-here-is-the-winds-have-changed/ 
    10-15 12:23:45.109 32635-32635/com.iboundiaye.newsreader I/id: 3 
    10-15 12:23:45.109 32635-32635/com.iboundiaye.newsreader I/article id: 12711343 
    10-15 12:23:45.109 32635-32635/com.iboundiaye.newsreader I/title: A single byte write opened a root execution exploit 
    10-15 12:23:45.109 32635-32635/com.iboundiaye.newsreader I/url: https://daniel.haxx.se/blog/2016/10/14/a-single-byte-write-opened-a-root-execution-exploit/ 
    10-15 12:23:45.109 32635-32635/com.iboundiaye.newsreader I/id: 4 
    10-15 12:23:45.109 32635-32635/com.iboundiaye.newsreader I/article id: 12711511 
    10-15 12:23:45.109 32635-32635/com.iboundiaye.newsreader I/title: Books Programmers Don't Really Read (2008) 
    10-15 12:23:45.109 32635-32635/com.iboundiaye.newsreader I/url: http://www.billthelizard.com/2008/12/books-programmers-dont-really-read.html 
    10-15 12:23:45.109 32635-32635/com.iboundiaye.newsreader I/id: 5 
    10-15 12:23:45.109 32635-32635/com.iboundiaye.newsreader I/article id: 12709220 
    10-15 12:23:45.109 32635-32635/com.iboundiaye.newsreader I/title: Intel will add deep-learning instructions to its processors 
    10-15 12:23:45.109 32635-32635/com.iboundiaye.newsreader I/url: http://lemire.me/blog/2016/10/14/intel-will-add-deep-learning-instructions-to-its-processors/ 
    10-15 12:23:45.109 32635-32635/com.iboundiaye.newsreader I/id: 6 
    10-15 12:23:45.109 32635-32635/com.iboundiaye.newsreader I/article id: 12707606 
    10-15 12:23:45.109 32635-32635/com.iboundiaye.newsreader I/title: Be Kind 
    10-15 12:23:45.109 32635-32635/com.iboundiaye.newsreader I/url: https://www.briangilham.com/blog/2016/10/10/be-kind 
    10-15 12:23:45.110 32635-32635/com.iboundiaye.newsreader I/id: 7 
    10-15 12:23:45.110 32635-32635/com.iboundiaye.newsreader I/article id: 12712577 
    10-15 12:23:45.110 32635-32635/com.iboundiaye.newsreader I/title: The Ops Identity Crisis 
    10-15 12:23:45.110 32635-32635/com.iboundiaye.newsreader I/url: http://www.susanjfowler.com/blog/2016/10/13/the-ops-identity-crisis 
    10-15 12:23:45.110 32635-32635/com.iboundiaye.newsreader I/id: 8 
    10-15 12:23:45.110 32635-32635/com.iboundiaye.newsreader I/article id: 12709820 
    10-15 12:23:45.110 32635-32635/com.iboundiaye.newsreader I/title: Easy Amazon EC2 Instance Comparison 
    10-15 12:23:45.110 32635-32635/com.iboundiaye.newsreader I/url: http://www.ec2instances.info/ 
    10-15 12:23:45.110 32635-32635/com.iboundiaye.newsreader I/id: 9 
    10-15 12:23:45.110 32635-32635/com.iboundiaye.newsreader I/article id: 12712454 
    10-15 12:23:45.110 32635-32635/com.iboundiaye.newsreader I/title: 5900 online stores found skimming 
    10-15 12:23:45.110 32635-32635/com.iboundiaye.newsreader I/url: https://gwillem.github.io/2016/10/11/5900-online-stores-found-skimming/

(статьи 10, включенной в конце)

источник

2016-10-13 Ibou92

если вставка не работает, то вы получите некоторое исключение в журналах вставить что –

Спасибо за ответ, на самом деле он просто возвращает базу данных с нулевым значением в заголовке и столбцах url – Ibou92

так что первичный ключ сгенерирован автоматически? и вы хотите вставить в ту же строку, то есть хотите обновить (сначала вставить строку) во вторую вставку или вставить другую новую строку? –

Попробуйте это: общественный класс MainActivity расширяет AppCompatActivity {

DownloadIdList idTask; 
DownloadArticle articleTask; 
SQLiteDatabase newsReaderDB; 

ListView listView; 
ArrayList<String> articlesList = new ArrayList<String>(); 
ArrayList<String> idList = new ArrayList<String>(); 
ArrayAdapter<String> arrayAdapter; 
int i=0; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 
    setSupportActionBar(toolbar); 

    idTask = new DownloadIdList(); 
    listView = (ListView) findViewById(R.id.listView); 
    arrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, articlesList); 
    listView.setAdapter(arrayAdapter); 

    try { 

     newsReaderDB = this.openOrCreateDatabase("News", MODE_PRIVATE, null); 

     newsReaderDB.execSQL("CREATE TABLE IF NOT EXISTS topStories (id INTEGER PRIMARY KEY, articleId INT(10), title VARCHAR, url VARCHAR)"); 

     //newsReaderDB.execSQL("DROP TABLE topStories"); 

     //Toast.makeText(getApplicationContext(),"Database deleted", Toast.LENGTH_LONG).show(); 

    } catch (Exception e) { 

     Toast.makeText(getApplicationContext(), "Can't create or open Database On Create", Toast.LENGTH_LONG).show(); 

    } 


    try { 

     idTask.execute("https://hacker-news.firebaseio.com/v0/topstories.json?print=pretty"); 

    } catch (Exception e) { 
      e.printStackTrace(); 
     Toast.makeText(getApplicationContext(),"Can't download URL", Toast.LENGTH_LONG).show(); 

    } 
} 

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

    @Override 
    protected String doInBackground(String... urls) { 

     String result = ""; 

     URL url; 

     HttpURLConnection urlConnection = null; 

     try { 

      url = new URL(urls[0]); 

      urlConnection = (HttpURLConnection) url.openConnection(); 

      InputStream inputStream = urlConnection.getInputStream(); 

      InputStreamReader reader = new InputStreamReader(inputStream); 

      int data = reader.read(); 

      while (data != -1) { 

       char current = (char) data; 

       result += current; 

       data = reader.read(); 

      } 

      return result; 

     }catch (Exception e) { 
      e.printStackTrace(); 
      Toast.makeText(getApplicationContext(),"Can't get Top Stories Id's" ,Toast.LENGTH_LONG).show(); 

     } 

     return null; 
    } 


    @Override 
    protected void onPostExecute(String result) { 
     super.onPostExecute(result); 

     try { 

      JSONArray idArray = new JSONArray(result); 

      for (int i=0; i < 10; i++) { 

       int value = idArray.getInt(i); 
       Log.i("Top Stories Id", String.valueOf(value)); 
       String id = String.valueOf(value); 
       idList.add(id); 
       /* articleTask = new DownloadArticle(); 

        try { 
         articleTask.execute("https://hacker-news.firebaseio.com/v0/item/" + id + ".json?print=pretty"); 


        } catch (Exception e) { 
         e.printStackTrace(); 
         Toast.makeText(getApplicationContext(),"can't get article info from id",Toast.LENGTH_LONG).show(); 

        }*/ 
      } 
for(int l=0;l<idList.size();l++){ 
    articleTask = new DownloadArticle(); 
i = l; 
        try { 
         articleTask.execute("https://hacker-news.firebaseio.com/v0/item/" + id + ".json?print=pretty"); 


        } catch (Exception e) { 
         e.printStackTrace(); 
         Toast.makeText(getApplicationContext(),"can't get article info from id",Toast.LENGTH_LONG).show(); 

        } 
} 
     }catch (JSONException e) { 
      e.printStackTrace(); 
      Toast.makeText(getApplicationContext(),"Can't get JSON Object",Toast.LENGTH_LONG).show(); 
     } 


    } 
} 

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

    @Override 
    protected String doInBackground(String... urls) { 

     String content = ""; 

     URL url; 

     HttpURLConnection urlConnection = null; 

     try { 

      url = new URL(urls[0]); 

      urlConnection = (HttpURLConnection) url.openConnection(); 

      InputStream inputStream = urlConnection.getInputStream(); 

      InputStreamReader reader = new InputStreamReader(inputStream); 

      int data = reader.read(); 

      while (data != -1) { 

       char current = (char) data; 

       content += current; 

       data = reader.read(); 

      } 

      return content; 

     } catch (Exception e) { 
      e.printStackTrace(); 
      Toast.makeText(getApplicationContext(), "Can't get Articles after retrieving the id", Toast.LENGTH_LONG).show(); 

     } 

     return null; 
    } 

    @Override 
    protected void onPostExecute(String content) { 
     super.onPostExecute(content); 

     try { 

      JSONObject jsonObject = new JSONObject(content); 

      int idInfo = jsonObject.getInt("id"); 
      String title = String.valueOf(jsonObject.getString("title")); 
      title = title.replaceAll("'","''"); 
      String urlien = String.valueOf(jsonObject.getString("url")); 


      //newsReaderDB = openOrCreateDatabase("News", MODE_PRIVATE, null); 
      newsReaderDB.execSQL("INSERT INTO topStories (articleId, title, url) VALUES(" + idInfo + ", '" + title + "','" + urlien + "');"); 
      if(i==(idList.size()-1){//last row is inserted in db 
       showData(); 
      } 



     }catch (JSONException e) { 
      e.printStackTrace(); 
      Toast.makeText(getApplicationContext(), "Can't get Article", Toast.LENGTH_LONG).show(); 

     } 
    } 
} 

/*public void showDatabase() { 

    try { 

     newsReaderDB = this.openOrCreateDatabase("News", MODE_PRIVATE, null); 

     Cursor c = newsReaderDB.rawQuery("SELECT * FROM topStories", null); 

     c.moveToFirst(); 

     int idIndex = c.getColumnIndex("id"); 

     int a_idIndex = c.getColumnIndex("articleId"); 

     int titleIndex = c.getColumnIndex("title"); 

     int urlIndex = c.getColumnIndex("url"); 

     c.moveToFirst(); 

     while (c != null) { 

      Log.i("Id", String.valueOf(c.getInt(idIndex))); 
      Log.i("Article id", String.valueOf(c.getInt(a_idIndex))); 
      Log.i("Title", c.getString(titleIndex)); 
      Log.i("Url Link", c.getString(urlIndex)); 

      c.moveToNext(); 
     } 

    } catch (Exception e) { 
     e.printStackTrace(); 
     Toast.makeText(getApplicationContext(), "Unable to List Database", Toast.LENGTH_LONG).show(); 
    } 
}*/ 

public void showData() { 
try { 
    Cursor cursor = newsReaderDB.rawQuery("SELECT * FROM topStories", null); 
    if (cursor.moveToFirst()) { 
     do { 
      String id = String.valueOf(cursor.getInt(cursor.getColumnIndex("id"))); 
      String a_id = String.valueOf(cursor.getInt(cursor.getColumnIndex("articleId"))); 
      String title = cursor.getString(cursor.getColumnIndex("title")); 
      String url = cursor.getString(cursor.getColumnIndex("url")); 

      Log.i("id", id); 
      Log.i("article id", a_id); 
      Log.i("title", title); 
      Log.i("url", url); 
     } while (cursor.moveToNext()); 
    } cursor.close(); 
}catch (Exception e) { 

    e.printStackTrace(); 
} 

} 

@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_main, 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); 
} 

}

источник

2016-10-13 17:35:30

Спасибо, это имеет смысл так! Но это все еще не позволит мне сохранить URL-адрес сейчас: я добавил e.printStackTrace() в catch текущего оператора UPDATE. Но это показывает это errororg.json.JSONException: Нет значения для url – Ibou92

Спасибо, это имеет смысл именно так! Но он все еще не позволит мне сохранить URL-адрес сейчас: я добавил e.printStackTrace() в catch текущего оператора UPDATE. Но он показывает эту ошибку "org.json.JSONException: Нет значения для URL-адреса". Значение в этом URL-адресе «http://petapixel.com/2016/10/11/cooled-nikon-d5500a-chills-sensor-clearer-star-photos/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%25253A+PetaPixel+ % 252528PetaPixel% 252529" . Это из-за плюсовых знаков в ссылке? я должен избегать их? – Ibou92

U может хранить его как строку вместо URL-адреса и вставлять ваш запрос на обновление, а также –

Просматривая базу данных с помощью курсоров, что-то не хватает?

ответ

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