将数据分配给 UILabel 后 UITableViewCell 显示不正确的数据

Question

我在处理UITableView 时遇到了一个有趣的问题。如果有人能指出我在哪里犯了错误，我将不胜感激。

所以，情况是：我有一个NSDictionaries 的NSArray，我试图让UITableView 中的每一行都显示相应的NSDictionary。下面是“cellForRowAtIndexPath”方法的代码片段：

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

    // configure custom cell
    static NSString *cellReuseId = @"cell";

    SearchTableViewCell *searchCell = [tableView dequeueReusableCellWithIdentifier:cellReuseId forIndexPath:indexPath];

    if (self.realData.count > 0) {
        self.tempDict = self.realData[indexPath.row];
        [searchCell initLabels:[self.tempDict valueForKey:@"psnname"] withDept:[self.tempDict valueForKey:@"deptname"] withPostion:[self.tempDict valueForKey:@"position"] withTel:[self.tempDict valueForKey:@"tel"] withFax:[self.tempDict valueForKey:@"fax"]];  
    } else {
        NSLog(@"no data");
    }
    return searchCell;
}

我创建了一个自定义 UITableViewCell，并尝试通过调用“initLabels...”方法在 custom UITableViewCell 中初始化五个 UILabels。下面是自定义UITableViewCellclass中的"initLabels..."方法：

-(void) initLabels:(NSString *)psn withDept:(NSString *)dept withPostion:(NSString *)pos withTel:(NSString *)tell withFax:(NSString *)faxx{
    int tempWidth = self.frame.size.width/5;

    self.psnname = [[UILabel alloc] initWithFrame:CGRectMake(self.frame.origin.x + 10, self.frame.origin.y, tempWidth * 0.8, self.frame.size.height)];
    self.deptname = [[UILabel alloc] initWithFrame:CGRectMake(self.frame.origin.x + self.psnname.frame.size.width + 5, self.frame.origin.y , tempWidth * 1.1, self.frame.size.height)];
    self.position = [[UILabel alloc] initWithFrame:CGRectMake(self.deptname.frame.origin.x + self.deptname.frame.size.width + 5, self.frame.origin.y , tempWidth * 1.1, self.frame.size.height)];
    self.tel = [[UILabel alloc] initWithFrame:CGRectMake(self.position.frame.origin.x + self.position.frame.size.width + 5, self.frame.origin.y , tempWidth * 0.7, self.frame.size.height)];
    self.fax = [[UILabel alloc] initWithFrame:CGRectMake(self.frame.size.width - tempWidth * 1.1, self.frame.origin.y , tempWidth, self.frame.size.height)];

    self.psnname.text = psn;
    self.deptname.text = dept;
    self.position.text = pos;
    self.tel.text = tell;
    self.fax.text = faxx;

    [self.contentView addSubview:self.psnname];
    [self.contentView addSubview:self.deptname];
    [self.contentView addSubview:self.position];
    [self.contentView addSubview:self.tel];
    [self.contentView addSubview:self.fax];
}

问题是：在使用NSString's 分配UILabel's 之前初始化那些UILabels 时，布局格式正确，但显示数据不正确；而如果在设置 UILabel 的框架之前使用 NSString 进行分配，则数据正确显示，但布局格式不正确。

导致这种情况发生的潜在原因是什么？？

Answer 1

您应该将构建自定义表格视图单元格的视图层次结构的代码与填充数据的代码分开。

在自定义表格视图单元格的init（或其初始化程序）中，添加以下内容：

self.psnname = [[UILabel alloc] initWithFrame:CGRectMake(self.frame.origin.x + 10, self.frame.origin.y, tempWidth * 0.8, self.frame.size.height)];
self.deptname = [[UILabel alloc] initWithFrame:CGRectMake(self.frame.origin.x + self.psnname.frame.size.width + 5, self.frame.origin.y , tempWidth * 1.1, self.frame.size.height)];
self.position = [[UILabel alloc] initWithFrame:CGRectMake(self.deptname.frame.origin.x + self.deptname.frame.size.width + 5, self.frame.origin.y , tempWidth * 1.1, self.frame.size.height)];
self.tel = [[UILabel alloc] initWithFrame:CGRectMake(self.position.frame.origin.x + self.position.frame.size.width + 5, self.frame.origin.y , tempWidth * 0.7, self.frame.size.height)];
self.fax = [[UILabel alloc] initWithFrame:CGRectMake(self.frame.size.width - tempWidth * 1.1, self.frame.origin.y , tempWidth, self.frame.size.height)];

[self.contentView addSubview:self.psnname];
[self.contentView addSubview:self.deptname];
[self.contentView addSubview:self.position];
[self.contentView addSubview:self.tel];
[self.contentView addSubview:self.fax];

然后在表格视图单元格子类中创建一个方法 - 如下所示 - 并从您的 cellForRowAtIndexPath 调用该方法

- (void)populateWithPSN:(NSString *)psn dept:(NSString *)dept postion:(NSString *)pos tel:(NSString *)tell fax:(NSString *)fax
{
    self.psnname.text = psn;
    self.deptname.text = dept;
    self.position.text = pos;
    self.tel.text = tell;
    self.fax.text = faxx;
}

Answer 2

另一种方法是，在自定义单元格的init方法中初始化标签并在layoutSubviews方法中设置标签的边框，该方法在单元格显示之前被多次调用，这是最好的地方设置标签的边框，例如，

在您的自定义单元格.m 文件中

-(void)layoutSubviews
{
   [super layoutSubviews];
   self.psnname.frame = CGRectMake(self.frame.origin.x + 10, self.frame.origin.y, tempWidth * 0.8, self.frame.size.height);
   self.deptname.frame = CGRectMake(self.frame.origin.x + self.psnname.frame.size.width + 5, self.frame.origin.y , tempWidth * 1.1, self.frame.size.height);
   self.position.frame = CGRectMake(self.deptname.frame.origin.x + self.deptname.frame.size.width + 5, self.frame.origin.y , tempWidth * 1.1, self.frame.size.height);
   self.tel.frame = CGRectMake(self.position.frame.origin.x + self.position.frame.size.width + 5, self.frame.origin.y , tempWidth * 0.7, self.frame.size.height);
   self.fax.frame = CGRectMake(self.frame.size.width - tempWidth * 1.1, self.frame.origin.y , tempWidth, self.frame.size.height);
}

为了设置数据，你可以使用你的方法，但为了更好的可读性，你可以像这样修改它

-(void)setLabels:(NSString *)psn withDept:(NSString *)dept withPostion:(NSString *)pos withTel:(NSString *)tell withFax:(NSString *)fax

对于细胞创建方法，

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

  // configure custom cell
  static NSString *cellReuseId = @"cell";

  SearchTableViewCell *searchCell = [tableView dequeueReusableCellWithIdentifier:cellReuseId forIndexPath:indexPath];

  if (self.realData.count > 0) {
      self.tempDict = self.realData[indexPath.row];
     [searchCell setLabels:[self.tempDict valueForKey:@"psnname"] withDept:[self.tempDict valueForKey:@"deptname"] withPostion:[self.tempDict valueForKey:@"position"] withTel:[self.tempDict valueForKey:@"tel"] withFax:[self.tempDict valueForKey:@"fax"]];  
  } else {
       NSLog(@"no data");
  }
  return searchCell;
}