UIActionSheet showInView 给出警告：无效上下文 0x0答案

【问题标题】：UIActionSheet showInView give warning : invalid context 0x0UIActionSheet showInView 给出警告：无效上下文 0x0
【发布时间】：2014-02-28 05:53:53
【问题描述】：

我正在尝试在self.view.parentview 中显示 UIActionSheet。但我在运行时收到以下警告

<Error>: CGContextSetFillColorWithColor: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context  and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.
<Error>: CGContextSetStrokeColorWithColor: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context  and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.
<Error>: CGContextSaveGState: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context  and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.

代码如下

self.dobActionSheet = [[UIActionSheet alloc] initWithTitle:nil delegate:nil cancelButtonTitle:nil destructiveButtonTitle:nil otherButtonTitles:nil,nil];
[self.dobActionSheet addSubview:self.doneForActionSheet];
[self.dobActionSheet addSubview:self.cancelForActionSheet];
[self.dobActionSheet addSubview:self.dobDatepicker];
[self.dobActionSheet showInView:self.parentViewController.view];

我已经设置了断点。但在这一行得到这个警告[self.dobActionSheet showInView:self.parentViewController.view];..

我尝试在第一个索引处显示Viewcontroller，即embedded in tabbarController。这就是为什么，尝试使用parentViewController.view 而不是self.view 进行演示

注意：我看到了同样的问题here。但找不到答案。

【问题讨论】：

试试 [self.dobActionSheet showInView:self.view];
我做不到。因为这个视图控制器在第一个索引处嵌入在 tabbarcontroller 中。这是正确的方法吗？任何方式都试过这个，但得到了同样的错误.. !!
可能重复：stackoverflow.com/a/19111512/544265
@c0ming 感谢您的链接。我已经尝试过了，但它对我不起作用。

标签： ios datepicker uiactionsheet

【解决方案1】：

actionSheet = [[UIActionSheet alloc] initWithTitle:@"Title"
                                              delegate:self
                                     cancelButtonTitle:nil
                                destructiveButtonTitle:nil
                                     otherButtonTitles:@"Ok"];

使用 @""

代替 nil 值

actionSheet = [[UIActionSheet alloc] initWithTitle:nil
delegate:nil
cancelButtonTitle:@""
destructiveButtonTitle:nil
otherButtonTitles:nil];

【讨论】：

操作表显示标题.. 所以我尝试使用单个空格作为标题。它正在工作。看我的回答..感谢+1你:)

【解决方案2】：

我已经从@Sunny shah 的回答中解决了这个问题。我已经尝试过他的回答，但在操作表上有title。相反，我尝试使用以下代码。（标题名称为单个空格）。

self.dobActionSheet = [[UIActionSheet alloc] initWithTitle:@" " delegate:nil cancelButtonTitle:nil destructiveButtonTitle:nil otherButtonTitles:nil,nil];

【讨论】：