使用场景之一,接收他人的项目,快速理清其层次结构,可以打标识符断点,如下图
每一个VC,都加了个在viewDidLoad方法处的断点,这样运行程序时,逐步断点,便可以理清层次,
但是,需要手动不断的继续,依旧不是很好 如果使用LLDB,就事半功倍~先上效果图
LIDB简史
Xcode5之前的调试器使用的是GDB,如果你不幸使用,那感觉简直了~然后伴随着Xcode5的发布,LLDB调试器取而代之,成为Xcode工程中默认的调试器,它和LVVM编译器一起,带给开发者丰富的流程控制和数据检测的调试功能.LLDB为Xcode提供了底层调试环境,其中,包括内嵌在Xcode IDE中的调试区域的控制面板,在这里我们可以直接调用LLDB命令.
chisel facebook团队良心出品的LLDB扩展
chisel 安装(需已有Homebrew,其安装很易,如若困惑可私信,这里不展开说明)
brew update brew install chisel
安装结束后会打印出路径如 /usr/local/opt/chisel/libexec/fblldb.py
添加下述命令行到 ~/.lldbinit filevi ~/.lldbinit...command script import /path/to/fblldb.py
_注意:_要将将上述/path/to/fblldb.py,路径替换为安装成功后的打印出路径如:/usr/local/opt/chisel/libexec/fblldb.py
特别的如果不存在~/.lldbinit file.
可以使用touch ~/.lldbinit 来创建它. 然后,需要重启Xcode,方能使之生效.
LLDB常见命令
| Command | Description | iOS | OS X |
|---|---|---|---|
| pviews | Print the recursive view description for the key window. | Yes | Yes |
| pvc | Print the recursive view controller description for the key window. | Yes | No |
| visualize | Open a UIImage, CGImageRef, UIView, CALayer, NSData (of an image), UIColor, CIColor, or CGColorRef in Preview.app on your Mac. | Yes | No |
| fv | Find a view in the hierarchy whose class name matches the provided regex. | Yes | No |
| fvc | Find a view controller in the hierarchy whose class name matches the provided regex. | Yes | No |
| show/hide | Show or hide the given view or layer. You don't even have to continue the process to see the changes! | Yes | Yes |
| mask/unmask | Overlay a view or layer with a transparent rectangle to visualize where it is. | Yes | No |
| border/unborder | Add a border to a view or layer to visualize where it is. | Yes | Yes |
| caflush | Flush the render server (equivalent to a "repaint" if no animations are in-flight). | Yes | Yes |
| bmessage | Set a symbolic breakpoint on the method of a class or the method of an instance without worrying which class in the hierarchy actually implements the method. | Yes | Yes |
| wivar | Set a watchpoint on an instance variable of an object. | Yes | Yes |
| presponder | Print the responder chain starting from the given object. | Yes | Yes |
| ... | ... and many more! |
pviews
该命令是最常用的命令，主要是用来查看布局中view的层级关系的。
border/unborder
这两个命令分别是给要查看的view添加边框和移除边框，可以在lldb下输入help border查看具体的用法，如果我要给第二个view添加一个颜色为蓝色，宽度为2的边框，之后再用unborder命令移除，操作如下：
通过help border命令知道border的使用格式如下： Options:--color/-c; Type: string; A color name such as 'red', 'green', 'magenta', etc. --width/-w ; Type: CGFloat; Desired width of border.Syntax: border [--color=color] [--width=width]
其中viewOrLayer表示你要修改的view的地址，我们通过pviews命令知道，第二个view的地址是0x7feae2d605f0，所以我们输入
border -c blue -w 2 0x7feae2d605f0 //添加边框unborder 0x7feae2d605f0 //移除边框
注意我在输入每个border/unborder命令时，右侧模拟器第二个view的变化。
view的层级关系。pinternals
这个命令主要是打印view的内部详细信息，太具体了，有需要的可以好好研究研究：
(lldb) pinternals 0x7fa59c2446f0(WKCompositingView) $451 = { UIView = { UIResponder = { NSObject = { isa = WKCompositingView } _hasAlternateNextResponder = false _hasInputAssistantItem = false } _constraintsExceptingSubviewAutoresizingConstraints = 0x00007fa59c248910 @"0 elements" _cachedTraitCollection = nil _layer = 0x00007fa599d81ba0 _layerRetained = nil _gestureInfo = nil _gestureRecognizers = nil _subviewCache = 0x00007fa599f027d0 @"0 elements" _templateLayoutView = nil _charge = 0 _tag = 0 _viewDelegate = nil _backgroundColorSystemColorName = nil _countOfMotionEffectsInSubtree = 0 _countOfTraitChangeRespondersInDirectSubtree = 0 _cachedScreenScale = 2 _retainCount = 4 _tintAdjustmentDimmingCount = 0 _shouldArchiveUIAppearanceTags = false _interactionTintColor = nil _layoutMarginsGuide = nil _minXVariable = 0x00007fa59c223790 _minYVariable = 0x00007fa59c2237b0 _boundsWidthVariable = 0x00007fa59c223ae0 _boundsHeightVariable = 0x00007fa59c223800 _layoutEngine = 0x00007fa59c014820 _layoutDebuggingIdentifier = nil _internalConstraints = nil _continuousCornerRadius = 0 _countOfFocusedAncestorTrackingViewsInSubtree = 0 _semanticContentAttribute = 0 __presentationControllerToNotifyOnLayoutSubviews = nil _previewingSegueTemplateStorage = nil _contentSizeNotificationToken = nil _readableContentGuide = 0x00007fee7c508a00 }} pclass
这个可以查看view的层级关系
图中先查看了UIView的层级关系，然后查看了一个第三方自定义的控件MMPlaceHolder的层级关系。
hide/show
这两个命令顾名思义，就是显示和隐藏某个指定的view，话不多说，上图(注意模拟器中第二个view的变化)：
taplog
这个命令在你点击屏幕后，lldb打印出你敲击屏幕时接收事件的view的信息。
注意，我是先输入的命令，然后点击了屏幕才打印出对应view的信息。
pvc
这个命令是打印当前的控制器层级，如下图，我定义了一个UINavigationController，ViewController作为它的根控制器。
bmessage
有这么中需求，在当前控制器没有实现某个方法（譬如：-viewWillAppear:）方法，但是我又想在该方法调用时触发中断，这个时候bmessage就派上用场了
(lldb) eobjc id $controller=(id)0x7fe8ab72ab50 //设置controller变量指向当前ViewController(lldb) bmessage [$controller viewDidAppear:] //给当前ViewController设置断点Setting a breakpoint at -[UIViewController viewDidAppear:] with condition (void*)(id)$rdi == 0x00007fe8ab72ab50Breakpoint 1: where = UIKit`-[UIViewController viewDidAppear:], address = 0x000000010e646d12
以上是Chisel最常用的一些命令.当然这个不是全部,算是抛砖引玉.欢迎一起交流.