/**
* 描述：删除关键字
*
* @param keyword
*/
public void delete(String keyword) {
SQLiteDatabase db = dbHelper.getWritableDatabase();
if (db.isOpen()) {
db.execSQL("delete from keywords where keyword=(?)", new Object[] {keyword});
db.close();
}
}
/**
* 描述：插入新的关键字
*
* @param keyword
*/
public void insert(String keyword) {
if (isExist(keyword)) { // 关键字已经存在于数据库中
return;
} else {
SQLiteDatabase db = dbHelper.getWritableDatabase();
if (db.isOpen()) {
db.execSQL("insert into keywords (keyword) values (?)", new Object[] {keyword});
db.close();
}
}
}
/**
* 描述：判断关键字是否存在于数据库中
*
* @param keyword
* @return
*/
public boolean isExist(String keyword) {
boolean result = false;
SQLiteDatabase db = dbHelper.getReadableDatabase();
if (db.isOpen()) {
Cursor cursor =
db.rawQuery("select keyword from keywords where keyword=?", new String[] {keyword});
if (cursor.moveToFirst()) {
result = true;
}
cursor.close();
db.close();
}
return result;
}
/**
* 描述：获取数据库中的所有数据
*
* @return
*/
public List<String> getKeywords() {
SQLiteDatabase db = dbHelper.getReadableDatabase();
List<String> keywords = new ArrayList<String>();
if (db.isOpen()) {
Cursor cursor = db.rawQuery("select keyword from keywords", null);
while (cursor.moveToNext()) {
String keyword = cursor.getString(cursor.getColumnIndex("keyword"));
keywords.add(keyword);
}
cursor.close();
db.close();
}
return keywords;
}