Objective-c IOS arm64方法调配失败调用原始方法

Question

我在ARMv7 IOS设备上使用标准方法调配,它对我来说非常完美.

但是当我编译arm64的代码时 - 它无法从新方法调用原始方法

我调配的主要目的 - 在我的应用程序的内部方法中使用参数在另一种方法中.

我有原始的方法-(void)insertdata:(id)text,我想改变它,-(void)patchedCall:(id)text并在新方法中调用原始方法.

码:

static IMP sOriginalImp = NULL;

@interface TextOverrides: NSObject
+(void)load;
-(void)patchedinsert:(id)text;
@end

@implementation TextOverrides

+(void)load
{
    //Get Implementation of original method

    Class originalClass = NSClassFromString(@"DataViewController");
    Method originalMeth = class_getInstanceMethod(originalClass, @selector(insertdata:));

    //Save original method implementation
    sOriginalImp = method_getImplementation(originalMeth);

    // Get implementation of replacement method
    Method replacementMeth = class_getInstanceMethod(NSClassFromString(@"TextOverrides"), @selector(patchedCall:));

    //Replace methods
    method_exchangeImplementations(originalMeth, replacementMeth);
}

-(void)patchedCall:(id)text
{
    @synchronized(self){
        //Call of original method that we save
        sOriginalImp(self, @selector(insertdata:), text);

        //Make our code for argument "text"
        printf("Here is data%s\n", [text UTF8String]);
    }
}

@end

在arm64架构上调用原始方法时代码失败:

//Call of original method that we save
sOriginalImp(self, @selector(insertdata:), text);

如何改进我的代码以在armv7和arm64上工作？

Answer 1

我不认为\xe2\x80\x99t 认为所有类的加载顺序都在某处指定。所以可能是该类TextOverrides之前加载过DataViewController，但在armv7上没有加载过。请参阅https://www.mikeash.com/pyblog/friday-qa-2009-05-22-objective-c-class-loading-and-initialization.html

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为了使其稳定，您应该只在类别 +load 方法中混合方法。例如：

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@interface DataViewController (TextOverrides)\n+(void)load;\n-(void)patchedinsert:(id)text;\n@end\n\n@implementation DataViewController (TextOverrides)\n\n+(void)load\n{\n    // swizzle here\n}\n...\n

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