Android Open Source - 2014-Droid-code Thirty

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License

The source code is released under:

GNU General Public License

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Java Source Code

package cs534.sample.dbAsyncTask;
// ww  w .  j  a  va  2s.  c  om
import android.app.Activity;
import android.database.Cursor;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.Toast;

/* 
 * Thirty.class
 * 
 * This is a very simple Activity 
 * It is used to populate and display the contents of a simple display
 * It uses a DBHelper class for the sqlite database
 * It uses the get30() DBHelper method for a subset of data
 * The onCreate() and onItemClick() are very similar to DatabaseActivity.class
 * I copied it for simplicity.
 * 
 * Again: Note this Activity performs queries on the UI thread, this is not a
 * good practice and can lead to ANR, lagging display etc.
 * Soon we will look at ways to avoid long running code on the main UI thread.
 */
public class Thirty extends Activity  {
  private DBHelper dbh;

  private SimpleCursorAdapter sca;
  private Cursor cursor;
  
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_30);
    // the projection (fields from the database that we want to use)
    String[] from = { DBHelper.COLUMN_ID,  DBHelper.COLUMN_CLASS,
        DBHelper.COLUMN_GRADE };
    // matching fields on the UI
    int[] to = { R.id.tvid, R.id.tvclass, R.id.tvgrade };
    dbh = DBHelper.getDBHelper(this);
    ListView lv = (ListView) findViewById(R.id.list30);
    
    /*
     * The helper returns a cursor, which is a set of database records.
     */
    cursor = dbh.get30();
    sca = new SimpleCursorAdapter(this, R.layout.id_mark_row, cursor, from,
        to, 0);

    lv.setAdapter(sca);
    lv.setOnItemClickListener(showThis);
  }

  /*
   * This is an Item Click Listener, for use with the ListView When an item in
   * the list is clicked, the corresponding database record is shown in a toast.
   */
  public OnItemClickListener showThis = new OnItemClickListener() {
    public void onItemClick(AdapterView<?> parent, View view, int position,
        long id) {
      Cursor temp = (Cursor) parent.getItemAtPosition(position);
      String firstName = temp.getString(temp.getColumnIndex(DBHelper.COLUMN_FIRST_NAME));
      String lastName = temp.getString(temp.getColumnIndex(DBHelper.COLUMN_LAST_NAME));
      
      Toast.makeText(getApplicationContext(), "Student: "+firstName+" "+lastName, Toast.LENGTH_SHORT).show();
    }
  }; // showThis()

}

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