如何检索tableview中的数据

Question

我成功地将数据添加到我的tableview，但是在表视图中它将检索新数据，旧数据将不会被替换，并且在表视图中它将检索2个相同的我添加的数据。意思我会有“测试，测试，嗨”，当我输入一个新的数据（再见，你好）我将有“测试，测试，嗨，测试，测试，嗨，再见，再见，你好”

if你需要额外的代码告诉我，谢谢。

我的代码：

 // ---Retrieve Rows--- 
    -(void) getAllRowsFromTableNamed: (NSString *) tableName { 
     [self openDB]; 
     NSString *qsql = @"SELECT * FROM Favourites"; 
     sqlite3_stmt *statement; 

     if (sqlite3_prepare_v2(db, [qsql UTF8String], -1, &statement, nil) == 
      SQLITE_OK) { 
      // Setup the SQL Statement and compile it for faster access 
      while (sqlite3_step(statement) == SQLITE_ROW) 
      { 

       // Read the data from the result row 
       char *field1 = (char *) sqlite3_column_text(statement, 0); 
       self.field1Str = [[NSString alloc] initWithUTF8String: field1]; 

       char *field2 = (char *) sqlite3_column_text(statement, 1); 
       self.field2Str = [[NSString alloc] initWithUTF8String: field2]; 


       NSString *stringValue = [[NSString alloc] initWithUTF8String: field1]; 
       [self.listArray addObject:stringValue]; 
       [stringValue release]; 

       NSLog(@"Address : %@ Description : %@", self.field1Str, self.field2Str); 

      } 
     } 
     // Release the compiled statement from memory 
     sqlite3_finalize(statement); 
     sqlite3_close(db); 
     NSLog(@"DATA RETRIEVED"); 
    } 
    //---End of Retrieve Row--- 



     - (NSInteger)tableView:(UITableView *)tableView 
     numberOfRowsInSection:(NSInteger)section 
     { 
      return [self.listData count]; 
     } 

     - (UITableViewCell *)tableView:(UITableView *)tableView 
       cellForRowAtIndexPath:(NSIndexPath *)indexPath 
     { 
      static NSString *TableIdentifier = @"TableIdentifier"; 
      UITableViewCell *cell = [tableView 
            dequeueReusableCellWithIdentifier:TableIdentifier]; 
      if (cell == nil) { 
       cell = [[[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault 
               reuseIdentifier:TableIdentifier] autorelease]; 
      } 

      NSUInteger row = [indexPath row]; 
      cell.textLabel.text = [listData objectAtIndex:row]; 
      return cell; 

     } 

    - (void) viewWillAppear:(BOOL)animated { 
     [self getAllRowsFromTableNamed:@"Favourites"]; 

     NSArray *array = [[NSArray alloc] initWithObjects:self.field1Str, self.field2Str, nil]; 

     [self.listArray addObjectsFromArray:array]; 
     [array release]; 
     [favouriteListTableView reloadData]; 
     //NSLog(@"String1:%@, String2:%@", self.string1, self.string2); 
    } 
============================================================================================ 
-(void) insertRecordIntoTableNamed: (NSString *) tableName 
         withField1: (NSString *) field1 field1Value: (NSString *) field1Value 
         andField2: (NSString *) field2 field2Value: (NSString *) field2Value { 
    [self openDB]; 
    NSString *sql = [NSString stringWithFormat: 
        @"INSERT OR REPLACE INTO '%@' ('%@', '%@') VALUES ('%@','%@')", 
        tableName, field1, field2, field1Value, field2Value]; 

    char *err; 
    if (sqlite3_exec(db, [sql UTF8String], NULL, NULL, &err) != SQLITE_OK) 
    { 
     sqlite3_close(db); 
     NSAssert(0, @"Error updating table."); 

    } 
    NSLog(@"DATA RECORDED"); 

} 

-(IBAction)doneButton:(id)sender { 
    if([addressTextField.text isEqualToString:@""] || [descriptionTextField.text isEqualToString:@""]){ 
     UIAlertView *alert = [[UIAlertView alloc] 
           initWithTitle:@"Invalid Input!" 
           message:@"Please enter Address or Description" 
           delegate:self 
           cancelButtonTitle:@"OK" 
           otherButtonTitles:nil]; 
     [alert show]; 
     [alert release]; 
    } 
    else{ 
    [self insertRecordIntoTableNamed:@"Favourites" 
          withField1:@"address" field1Value:addressTextField.text 
          andField2:@"description" field2Value:descriptionTextField.text]; 

    NSArray *viewControllers = [self.navigationController viewControllers]; 

    FavouriteListViewController *favouriteListVC = (FavouriteListViewController *)[viewControllers objectAtIndex:viewControllers.count - 2]; 

    [favouriteListVC setString1:self.field1Str]; 
    [favouriteListVC setString2:self.field2Str]; 
    [self.navigationController popViewControllerAnimated:YES]; 
    } 
} 

Answer 1

你必须从数据库中检索他们之后将数据添加到了listData阵列。

while (sqlite3_step(statement) == SQLITE_ROW) 
     { 
      // Read the data from the result row 
      char *field1 = (char *) sqlite3_column_text(statement, 0); 
      NSString *stringValue = [[NSString alloc] initWithUTF8String: field1]; 
      [self.listData addObject:stringValue]; 
      [stringValue release]; 

     } 

您只获取行，因为在listData数组中只有两个对象存在。