Question

我无法弄清楚如何在我的UITableViewController中的headerView中重新显示我更改的文本。我做了一个“removeFromSuperview”，它确实被删除了，但是当我将它重新添加到我的subView后它不会重新显示新的headerView。这是我的代码：

    - (UIView *)headerView
    {
    if (headerView){
        [headerView removeFromSuperview];
        [headerView release];
    }
    UIButton *headerLabel = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    if (displayOnly == NO)
        [headerLabel setTitle:@"Click here to switch to display only mode." forState:UIControlStateNormal];
    else
        [headerLabel setTitle:@"Click here to switch to practice session mode." forState:UIControlStateNormal];
    float w = [[UIScreen mainScreen] bounds].size.width;
    CGRect headerLabelFrame = CGRectMake(8.0, 8.0, w - 16.0, 30.0);
    [headerLabel setFrame:headerLabelFrame];
    CGRect headerViewFrame = CGRectMake(0, 0, w, 48);
    [headerLabel addTarget:self action:@selector(switch) forControlEvents:UIControlEventTouchUpInside];
    headerView = [[UIView alloc] initWithFrame:headerViewFrame];
    [headerView addSubview:headerLabel];
    return headerView;
}
- (void) switch
{
    if (displayOnly == YES)
    {
        displayOnly = NO;
        [self headerView];
    }  
    else
    {
        displayOnly = YES;
        [self headerView]; 
    }
}

Answer 1

您是否尝试过调试应用？你在表中添加headerView的位置？你需要像这样改变代码

- (void) switch
{
    if (displayOnly == YES)
    {
        displayOnly = NO;
        self.tableView.tableHeaderView = [self headerView];    
    }  
    else
    {
        displayOnly = YES;
        self.tableView.tableHeaderView = [self headerView];    
    }
}

Answer 2

您是否在设置新标题后尝试拨打[headerView setNeedsDisplay];而不是每次都重新创建视图？也许你根本不需要这样做。如果您存储UIButton和UIView，如果我是对的，当您为其添加新标题时，它会自动重绘。像这样：

你的.h文件中的

UIButton* headerLabel;
UIView*   headerView;

并在您的.m文件中

- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section {
    return [self headerView]; 
}

- (UIView *)headerView{
    if(headerView){
        return headerView;
    }
    if(!headerLabel){
        headerLabel = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    }
    if (displayOnly == NO)
        [headerLabel setTitle:@"Click here to switch to display only mode." forState:UIControlStateNormal];
    else
        [headerLabel setTitle:@"Click here to switch to practice session mode." forState:UIControlStateNormal];
    float w = [[UIScreen mainScreen] bounds].size.width;
    CGRect headerLabelFrame = CGRectMake(8.0, 8.0, w - 16.0, 30.0);
    [headerLabel setFrame:headerLabelFrame];
    CGRect headerViewFrame = CGRectMake(0, 0, w, 48);
    [headerLabel addTarget:self action:@selector(switch) forControlEvents:UIControlEventTouchUpInside];
    headerView = [[UIView alloc] initWithFrame:headerViewFrame];
    [headerView addSubview:headerLabel];
    return headerView;
}

- (void) switch{
    if (displayOnly == YES){
        displayOnly = NO;
        [headerLabel setTitle:@"Click here to switch to display only mode." forState:UIControlStateNormal]; 
    }  else{
        displayOnly = YES;
        [headerLabel setTitle:@"Click here to switch to practice session mode." forState:UIControlStateNormal];  
    }
    //may be there's need to make additional call
    [headerView setNeedsDisplay];
}

这样您就可以保持UIView和UIButton的同一个实例，只更新它的标题，并可能通过拨打[headerView setNeedsDisplay];来手动调用重绘。

Answer 3

在此代码中：

if (headerView){
    [headerView removeFromSuperview];
    [headerView release];
}

您从超级视图中删除了headerView，但在创建新的headerView之后却未将其添加到超级视图中。

Answer 4

我认为您需要调用表重新加载数据然后才能工作。

无法在UITableViewController中重新显示更改的headerView文本

4 个答案: