无法通过lldb计算属性的值。

Question

在我的课堂上，我有一项财产

@property (nonatomic, retain) UIBarButtonItem *allMediaButton;

在我的代码中，我使用setEnabled: setter启用和禁用此控件。

但是，在调试窗口中，我无法检查属性值。

我尝试了不同的方法：

(lldb) po (UIBarItem*)appdelegate.detailViewController.allMediaButton
(UIBarItem *) $1 = 0x08302ed0 <UIBarButtonItem: 0x8302ed0>

(lldb) po (UIBarItem*)appdelegate.detailViewController.allMediaButton.enabled
error: property 'enabled' not found on object of type 'UIBarButtonItem *'
error: 1 errors parsing expression

(lldb) expr (UIBarItem*)appdelegate.detailViewController.allMediaButton.enabled
error: property 'enabled' not found on object of type 'UIBarButtonItem *'
error: 1 errors parsing expression

(lldb) expr ((UIBarItem*)appdelegate.detailViewController.allMediaButton).enabled
error: property 'enabled' not found on object of type 'UIBarItem *'
error: 1 errors parsing expression

(lldb) expr ((UIBarItem*)appdelegate.detailViewController.allMediaButton).enabled
error: property 'enabled' not found on object of type 'UIBarItem *'
error: 1 errors parsing expression

(lldb) po ((UIBarItem*)appdelegate.detailViewController.allMediaButton).enabled
error: property 'enabled' not found on object of type 'UIBarItem *'
error: 1 errors parsing expression

(lldb) po ((UIBarItem*)appdelegate.detailViewController.allMediaButton).isEnabled
error: property 'isEnabled' not found on object of type 'UIBarItem *'
error: 1 errors parsing expression

(lldb) expr ((UIBarItem*)appdelegate.detailViewController.allMediaButton).isEnabled
error: property 'isEnabled' not found on object of type 'UIBarItem *'
error: 1 errors parsing expression

(lldb) expr appdelegate.detailViewController.allMediaButton.isEnabled
error: property 'isEnabled' not found on object of type 'UIBarButtonItem *'
error: 1 errors parsing expression

(lldb) po  appdelegate.detailViewController.allMediaButton.isEnabled
error: property 'isEnabled' not found on object of type 'UIBarButtonItem *'
error: 1 errors parsing expression

(lldb) po  appdelegate.detailViewController.allMediaButton.enabled
error: property 'enabled' not found on object of type 'UIBarButtonItem *'
error: 1 errors parsing expression

(lldb) expr  appdelegate.detailViewController.allMediaButton.enabled
error: property 'enabled' not found on object of type 'UIBarButtonItem *'
error: 1 errors parsing expression

我怎样才能看到财产的价值？

更新: po @()也不起作用：

(lldb) po  @([[[appdelegate detailViewController] allMediaButton] isEnabled])
error: no known method '-isEnabled'; cast the message send to the method's return type
error: 1 errors parsing expression

(lldb) po  @([(UIBarItem)[[appdelegate detailViewController] allMediaButton] isEnabled])
error: C-style cast from 'UIBarButtonItem *' to 'UIBarItem' is not allowed
error: 1 errors parsing expression

(lldb) po  @([(UIBarItem*)[[appdelegate detailViewController] allMediaButton] isEnabled])
error: no known method '-isEnabled'; cast the message send to the method's return type
error: 1 errors parsing expression

(lldb) po  @([((UIBarItem*)[[appdelegate detailViewController] allMediaButton]) isEnabled])
error: no known method '-isEnabled'; cast the message send to the method's return type
error: 1 errors parsing expression

Answer 1

而不是

po @(scalar)

使用

p scalar

Answer 2

您不能(po)这样打印对象，因为实际上enabled属性不是对象类型，而是标量。你可以试试po @( your scalar value here )。

另一件非常重要的事情是，尝试执行以下操作以获得对属性的访问，而无需强制转换

po @([[[appdelegate detailViewController] allMediaButton] isEnabled])

那应该对你有用