Android Open Source - sloop-sql Script Fragment

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License

The source code is released under:

SloopSQL is released into the Public Domain. There are no restrictions on how you may use this code, and there is no warranty or guarantee of fitness for anything. USE AT YOUR OWN RISK (and enjoy).

Java Source Code

package com.megginson.sloopsql;
//from w w w . jav  a 2 s.  co m
import android.app.Fragment;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.view.inputmethod.EditorInfo;
import android.widget.ArrayAdapter;
import android.widget.AutoCompleteTextView;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.TextView;
import com.megginson.sloopsql.R;
import java.util.ArrayList;
import java.util.List;

/**
 * Activity for executing SQL queries.
 */
public class ScriptFragment extends Fragment
{

    //
  // Constants
  //

  /**
   * Property name for saved SQL query.
   */
  public final static String SCRIPT_TEXT_PROPERTY = "queryText";


  /**
   * Static constructor
   */
  public final static ScriptFragment newInstance(String scriptText)
  {
    ScriptFragment fragment =new ScriptFragment();
    fragment.mScriptText = scriptText;
    return fragment;
  }


  //
  // Internal fragment state
  //

  /**
   * The fragment's root view. set in {@link #onCreateView}
   */
  private View mFragmentView;

  /**
   * The database we're currently querying.
   */
  private SQLiteDatabase mDatabase;

  /**
   * The current SQL query text.
   */
  private String mScriptText;

  //
  // Fragment lifecycle methods
  //

    /** 
   * Lifecycle event: fragment first created.
   */
    @Override
    public void onCreate(Bundle savedInstanceState)
  {
        super.onCreate(savedInstanceState);
    setHasOptionsMenu(true);

    if (savedInstanceState != null)
    {
      mScriptText = savedInstanceState.getString(SCRIPT_TEXT_PROPERTY);
    }

    mDatabase = new DatabaseHandler(getActivity()).getReadableDatabase();
    }

  /**
   * Lifecycle event: fragment destroyed.
   */
  @Override
  public void onDestroy()
  {
    super.onDestroy();

    // free resources

    if (mDatabase != null)
    {
      mDatabase.close();
      mDatabase = null;
    }
  }

  /**
   * Lifecycle event: fragment creates or recreates its view.
   */
  @Override
  public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
  {
    mFragmentView = inflater.inflate(R.layout.script, container, false);

    setup_ui();

    return mFragmentView;
  }

  /**
   * Lifecycle event: Android wants us to save the instance state.
   */
  @Override
  public void onSaveInstanceState(Bundle savedInstanceState)
  {
    savedInstanceState.putString(SCRIPT_TEXT_PROPERTY, mScriptText);
  }

  /**
   * Lifecycle event: Android is creating the options menu.
   */
  @Override
  public void onCreateOptionsMenu(Menu menu, MenuInflater inflater)
  {
    inflater.inflate(R.menu.script_menu, menu);
  }

  /**
   * Lifecycle event: the user has selected a menu item.
   */
  @Override
  public boolean onOptionsItemSelected(MenuItem item)
  {
    // Handle item selection
    switch (item.getItemId())
    {
      case R.id.item_execute_script:
        do_execute_script();
        return true;
      default:
        return super.onOptionsItemSelected(item);
    }
  }


  //
  // Callbacks for actions a user has performed in the UI
  //

  /**
   * Action: execute the SQL script.
   *
   * Use the text content of {@link #mQueryView} for the query and assign
   * to {@link #mQueryText}
   */
  private void do_execute_script()
  {    
    mScriptText = get_script_view().getText().toString();

    if (mScriptText != null && mScriptText.length() > 0)
    {
      String statements[] = Util.splitSQL(mScriptText).toArray(new String[0]);
      if (statements.length > 0)
      {
        new QueryTask().execute(statements);
        return;
      }
    }
  }

  //
  // UI methods
  //
  // (It's not safe to store references to UI components directly
  // in variables, since the fragment's state can outlast UI
  // changes, so we use dynamic accessors instead.)
  //

  /**
   * Set up the UI components of the activity.
   */
  private void setup_ui()
  {
    EditText scriptView = get_script_view();
    scriptView.setText(mScriptText);
  }

  /**
   * Get the script edit view from the UI.
   *
   * This is the view that holds the SQL text for our script.
   *
   * @return the script view, or null if the UI isn't set up.
   */
  private EditText get_script_view()
  {
    if (mFragmentView != null)
    {
      return (EditText)mFragmentView.findViewById(R.id.edit_script);
    }
    else
    {
      return null;
    }
  }


  //
  // Internal helper classes
  //

  /**
   * Task for running a database query in the background.
   */
  private class QueryTask extends AsyncTask<String, Integer, AsyncResult<Cursor>>
  {

    /**
     * Text of the SQL query.
     */
    private String mScriptText;


    /**
     * Run the SQL query
     *
     * This method runs in a background thread.  The {@link ASyncTask}
     * takes care of getting it to {@link #onPostExecute} in the
     * main thread.
     *
     * @param queries An array of SQL queries to execute (always
     * just one for now)
     * @return The result of executing the query.
     */
    @Override
    protected AsyncResult<Cursor> doInBackground(String ... queries)
    {
      Cursor cursor = null;
      try
      {
        for (int i = 0; i < queries.length; i++)
        {
          cursor = mDatabase.rawQuery(queries[i], null);
          // save the successful query text
          mScriptText = queries[i];
        } 
        return new AsyncResult<Cursor>(cursor);
      }
      catch (Throwable t)
      {
        return new AsyncResult<Cursor>(t);
      }
    }

    /**
     * Handle the SQL result
     * 
     * This method runs in the main UI thread.  It receives the
     * rescult of {@link #doInBackground}, and can use it to
     * modify the UI safely.
     *
     * @param result The result of the background query.
     */
    @Override
    protected void onPostExecute(AsyncResult<Cursor> result)
    {
      // If there's an error, tell the user and proceed no further.
      if (result.isError())
      {
        Util.toast(getActivity(), result.getThrowable().getMessage());
        return;
      }

      // Register the new query result
      Cursor cursor = result.getResult();
      if (result == null)
      {
        return;
      }

      // Look up the views we're going to need.
      TextView messageView = (TextView)mFragmentView.findViewById(R.id.text_message);

      // Set up the message view.
      messageView.setText(String.format(getString(R.string.message_query_result), cursor.getCount()));
      cursor.close();  
    }

  }

}

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