为什么我的UITableView从UITableViewStyleGrouped更改为UITableViewStylePlain [英] Why does my UITableView change from UITableViewStyleGrouped to UITableViewStylePlain

问题描述

我的应用程序有一个扩展 UITableViewController 的视图控制器.初始化方法如下:

My application has a view controller that extends UITableViewController. The initialization method looks like this:

- (id)initWithCoder:(NSCoder*)coder {
    if (self = [super initWithCoder:coder]) {
        self.tableView = [[UITableView alloc] initWithFrame:self.tableView.frame 
                                                      style:UITableViewStyleGrouped];
    }

    return self;
}

最初加载视图时，它显示为 UITableViewStyleGrouped .但是，如果我的应用程序收到内存不足警告，则以上视图将更改为 UITableViewStylePlain .没有与视图/控制器关联的xib文件.viewDidUnload和didReceiveMemoryWarning方法很简单:

When the view is initially loaded, it's displayed as UITableViewStyleGrouped. However, if my app ever receives a low memory warning, the above view changes to UITableViewStylePlain. There is no associated xib file with the View/Controller. The viewDidUnload and didReceiveMemoryWarning methods are straightforward:

- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Release any cached data, images, etc that aren't in use.
}

- (void)viewDidUnload {
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}

我的问题是，当我收到内存警告时，为什么表格样式会更改?

My question is, why does the table style change when I receive a memory warning?

它在设备和模拟器上发生.该设备是运行OS 3.1.3的3G iphone，模拟器正在运行OS 3.1

It happens on the device and on the simulator. The device is a 3G iphone running OS 3.1.3, the simulator is running OS 3.1

推荐答案

在初始化中，您调用 [super initWithCoder:coder] .最好为 UITableViewController 覆盖指定的初始化程序，该初始化程序为 -initWithStyle:.可能发生的情况是，当您通过调用 [super init ...] 创建表视图控制器时，它是在已设置其 tableView 属性的情况下创建的；也就是说，它将在初始化时创建表视图.这就是为什么您对 self.tableView.frame 的调用起作用的原因-如果 self.tableView 的值为 nil ，则该调用不起作用.这是一个更好的实现:

In your initialization, you call [super initWithCoder:coder]. It would probably be better to override the designated initializer for UITableViewController, which is -initWithStyle:. What's probably happening is that when you create the table view controller by calling [super init…], it's being created with its tableView property already being set; that is, it's creating the table view on initialization. That's why your call to self.tableView.frame works—that shouldn't work if the value of self.tableView is nil. Here's a better implementation:

- (id)initWithCoder:(NSCoder*)coder {
    if (self = [super initWithStyle:UITableViewStyleGrouped]) {

    }

    return self;
}

这篇关于为什么我的UITableView从UITableViewStyleGrouped更改为UITableViewStylePlain的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！