iOS安全使用私有framework

获取私有framework中某subview对象

博客：using private iOS APIs safely 深度递归查找子view，修改其属性： You are not prevented from modifying a view that is part of a UIKit object, you just need to do it publicly. The [UIView subviews]method is public, and you can use this to dig through the view hierarchy looking for a private view to change, no private method calls required

1. [UIView subviews]

NS_INLINE UIView *UIFindSubview(UIView *view, Class viewClass) { for (UIView *subview in view.subviews) { if ([subview isKindOfClass:viewClass]) { return subview; } else { UIView *rect = UIFindSubview(subview, viewClass); if (rect) { return rect; } } } return nil; }

调用此方法获取一个subView

UIView *view = findSubview(picker.view, [NSClassFromString(@"CMKVideoPreviewView") class]);

2.[[subview class] description]

博客：Removing reorder cell shadows from a UITableView

我们无法直接使用私有类的声明，但是我们可以用[[subview class] description]来获取class的信息。[[[subview class] description] isEqualToString:@”UIShadowView”] You don’t have a class declaration for the private classes, but that’s fine, instead you can evaluate that it is correct based on class string description, [[[subview class] description] isEqualToString:@”UIShadowView”]

// iOS7 for(UIView* subview in wrapperView.subviews) { if([[[subview class] description] isEqualToString:@"UIShadowView"]) [subview setHidden:YES]; }

私有头文件

You can use a tool like class-dump or a private class reference to see every Objective-C method each class in iOS has – the truth is nothing in Objective-C is truly ‘private’, you can see any method compiled into the binary.

我们可以用class-dump o 或者 private class reference这些工具看到iOS中所有class的方法.但是私有头API会随时下掉，所以建议用respondsToSelector: 和 performSelector:来检查一下该方法是否可以用

访问实例变量

如何访问类中私有变量？ 比如下面，[xxxx valueForKey:@”_internal”] 可以返回 private变量 _internal 。

NS_CLASS_AVAILABLE_IOS(2_0) @interface UIWebView : UIView { @private UIWebViewInternal *_internal; }

但是如果，我们 请求的变量不存在（根据我们输入的key值没有找到相应的value），程序会 crash。为了防止这种情况，我们可以在 NSObject的categorise中或者 写一个子类继承该类，并重写valueForUndefinedKey方法。

- (id) valueForUndefinedKey:(NSString *)key { // No crashes please... return nil; }

我们有时候改变只读属性的实例变量的值，就可以这样用。我之前试过强制设置orientation属性值 。

Method Swizzling

Method SwizzlingMethod Swizzling Method Swizzling lets you inject code in the middle of two existing classes, which can be a lot more beneficial compared to a subclass that will only add your code on top of one class that must be subclassed.example

访问私有枚举变量

私有枚举变量，本质上就是一些数字。比如下面的例子，返回的按钮UIButtonType的值是101, 私有不公开。我们可以直接设置：

UIButton* back = [UIButton buttonWithType:101]; [back sizeToFit]; [back setTitle:@"Back" forState:UIControlStateNormal]; image

C方法

One half of Objective-C is pure C, and with that all the tricks to incorporate private C APIs into your app, such as defining external functions。 例子：截屏并保存图片

CGImageRef screenshot = UIGetScreenImage(); UIImage* image = [UIImage imageWithCGImage:screenshot]; [UIImagePNGRepresentation(image) writeToFile:@"/maybe-change-this.png" atomically:NO];

重写私有方法和类

重写私有方法和类，并不会让app被App store拒绝，但是你的app会变的不稳定。每次版本更新，都需要去检查，你的方法或者类是否正常工作。我们可以重写public或者private 类的私有方法。如果是私有类，直接重写会导致编译错误，但是你可以为它添加一个fake interface,categorise.

例子：重写UIStatusBar类

@interface UIStatusBar : UIView @end @interface UIStatusBar (Override) @end @implementation UIStatusBar (Override) - (void) drawRect:(CGRect)rect { NSArray* subviews = self.subviews; if(subviews.count < 2) return; UIView* background = [subviews objectAtIndex:0]; UIView* foreground = [subviews objectAtIndex:1]; [UIView animateWithDuration:2 animations:^{ [self setTransform:CGAffineTransformMakeTranslation(0, 100)]; [background setTransform:CGAffineTransformMakeTranslation(-160, 0)]; [foreground setTransform:CGAffineTransformMakeTranslation(160, 0)]; }]; } @end

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private framework使用dylib注射获取私有apiios逆向工程