如何使用 Xcode 调试器打印出属性的内容? [英] How to print out a property's contents using Xcode debugger?

问题描述

我正在编写一个 iOS 应用程序，我需要使用内置 Xcode 调试器的帮助.假设我有一个名为 HomeViewController 的对象，它具有三个属性

I'm writing an iOS app and I need help using the built-in Xcode debugger. Suppose I have an object called HomeViewController that has three properties

@property (nonatomic) BOOL finished;
@property (nonatomic, strong) NSArray *myArray;
@property (nonatomic, strong) NSString *myName;

@synthesize finished = _finished, myArray = _myArray, myName = _myName;

假设我在这个类中有一个断点.我将如何查看这些属性的内容?我已经尝试过诸如 po myName、print myName 和 print [self myName] 之类的东西，但我不知道该怎么做.我尝试过使用 LLDB，但我一直收到这个人遇到的相同错误(lldb 无法打印变量值并出现错误:对 'id' 的引用不明确").这个问题的公认答案是，LLDB 坏了，我应该只使用 GDB；但是，我拒绝接受如此基本的东西被破坏了.

Suppose I have a breakpoint in this class. How would I view the contents of these properties? I've tried things such as po myName, print myName and print [self myName] but I can't figure out how to do this. I've tried using LLDB but I keep getting the same error that this person encountered (lldb fails to print variable values with "error: reference to 'id' is ambiguous") . The accepted answer to this question was, LLDB is broken and that I should just use GDB; however, I refuse to accept that something so fundamental is broken.

尽管如此，我也尝试过使用 GDB 和上面类似的命令；但是，我也无法让 GDB 工作.请帮忙

Nevertheless, I've also tried using GDB with similar commands as above; however, I can't get GDB to work either. Help please

推荐答案

放置断点后，运行，程序停在断点处，将光标悬停在你想看到的变量/值上，如下所示:

Once you place a breakpoint, run, and the program stops at the breakpoint, hover your cursor over the variable/value you want to see like this:

您还可以放置一个 NSLog(@"%@", yourLabel.text); 来查看该标签/其他对象类型的内容.

You could also place an NSLog(@"%@", yourLabel.text); to view the contents of that label/other object type.

另一种选择是在控制台中运行 GDB，如下所示:

One other option is to run GDB in the console like this:

gdb
attach <your process name>

然后使用po(print-object)命令查看变量的值，如下:

And then use the po (print-object) command to view the value of a variable like this:

po variableName

查看原始类型的值(int、float、long、double、char 等)，您可以在控制台中运行 GDB 时使用 print 命令，如下所示:

To view the value of primitive types (int, float, long, double, char, etc.), you can just use the print command while running GDB in the console like this:

print yourPrimitiveVariable

希望这会有所帮助！

使用 po 命令，您可以使用属性名称 (self.myProperty) 或 ivar 名称(可能是 _myProperty).我在这里演示一下:

With the po command, you can print out the value of an object using both the property name (self.myProperty) or the ivar name (possibly _myProperty). I demonstrate this here:

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