Android DB資料庫執行個體

主要代碼：

package eoe.demo;

import android.app.Activity;
import android.database.Cursor;
import android.database.sqlite.SQLiteCursor;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;

public class DBActivity extends Activity {

private ToDoDB myToDoDB;
private Cursor myCursor;
private ListView myListView;
private EditText myEditText;
private int _id;
protected final static int MENU_ADD = Menu.FIRST;
protected final static int MENU_EDIT = Menu.FIRST + 1;
protected final static int MENU_DELETE = Menu.FIRST + 2;

public boolean onOptionsItemSelected(MenuItem item)
{
super.onOptionsItemSelected(item);
switch (item.getItemId())
{
case MENU_ADD:
this.addTodo();
break;
case MENU_EDIT:
this.editTodo();
break;
case MENU_DELETE:
this.deleteTodo();
break;
}
return true;
}

public boolean onCreateOptionsMenu(Menu menu)
{
super.onCreateOptionsMenu(menu);
menu.add(Menu.NONE, MENU_ADD, 0, R.string.strAddButton);
menu.add(Menu.NONE, MENU_EDIT, 0, R.string.strEditButton);
menu.add(Menu.NONE, MENU_DELETE, 0, R.string.strDeleteButton);

return true;
}

public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

myListView = (ListView) this.findViewById(R.id.myListView);
myEditText = (EditText) this.findViewById(R.id.myEditText);

myToDoDB = new ToDoDB(this);
/* 取得DataBase裡的資料 */
myCursor = myToDoDB.select();

/* new SimpleCursorAdapter並將myCursor傳入，
顯示資料的欄位為todo_text */
SimpleCursorAdapter adapter = 
new SimpleCursorAdapter
(this, R.layout.list, myCursor, new String[]
{ ToDoDB.FIELD_TEXT }, new int[]
{ R.id.listTextView1 });
myListView.setAdapter(adapter);

/* 將myListView添加OnItemClickListener */
myListView.setOnItemClickListener
(new AdapterView.OnItemClickListener()
{

public void onItemClick
(AdapterView<?> arg0, View arg1, int arg2, long arg3)
{
/* 將myCursor移到所點擊的值 */
myCursor.moveToPosition(arg2);
/* 取得欄位_id的值 */
_id = myCursor.getInt(0);
/* 取得欄位todo_text的值 */
myEditText.setText(myCursor.getString(1));
}

});
myListView.setOnItemSelectedListener
(new AdapterView.OnItemSelectedListener()
{
public void onItemSelected
(AdapterView<?> arg0, View arg1, int arg2, long arg3)
{
/* getSelectedItem所取得的是SQLiteCursor */
SQLiteCursor sc = (SQLiteCursor) arg0.getSelectedItem();
_id = sc.getInt(0);
myEditText.setText(sc.getString(1));
}

public void onNothingSelected(AdapterView<?> arg0)
{
}
});
}

private void addTodo()
{
if (myEditText.getText().toString().equals(""))
return;
/* 添加資料到資料庫 */
myToDoDB.insert(myEditText.getText().toString());
/* 重新查詢 */
myCursor.requery();
/* 重新整理myListView */
myListView.invalidateViews();
myEditText.setText("");
_id = 0;
}

private void editTodo()
{
if (myEditText.getText().toString().equals(""))
return;
/* 修改資料 */
myToDoDB.update(_id, myEditText.getText().toString());
myCursor.requery();
myListView.invalidateViews();
myEditText.setText("");
_id = 0;
}

private void deleteTodo()
{
if (_id == 0)
return;
/* 刪除資料 */
myToDoDB.delete(_id);
myCursor.requery();
myListView.invalidateViews();
myEditText.setText("");
_id = 0;
}
 

}

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