在iOS開(kāi)發(fā)中需要保證所有UI操作一定是在主線(xiàn)程進(jìn)行，通過(guò) hook UIView的-setNeedsLayout加缘，-setNeedsDisplay，-setNeedsDisplayInRect三個(gè)方法醋界，確保它們都是在主線(xiàn)程執(zhí)行湖蜕。
#import "UIView+NBUIKitMainThreadGuard.h"
#import <objc/runtime.h>
static inline void swizzling_exchangeMethod(Class clazz ,SEL originalSelector, SEL swizzledSelector){
Method originalMethod = class_getInstanceMethod(clazz, originalSelector);
Method swizzledMethod = class_getInstanceMethod(clazz, swizzledSelector);
BOOL success = class_addMethod(clazz, originalSelector, method_getImplementation(swizzledMethod), method_getTypeEncoding(swizzledMethod));
if (success) {
class_replaceMethod(clazz, swizzledSelector, method_getImplementation(originalMethod), method_getTypeEncoding(originalMethod));
} else {
method_exchangeImplementations(originalMethod, swizzledMethod);
}
}
@implementation UIView (NBUIKitMainThreadGuard)
+(void)load
{
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
SEL needsLayoutOriginalSelector = @selector(setNeedsLayout);
SEL needsLayoutSwizzleSelector = @selector(guard_setNeedsLayout);
swizzling_exchangeMethod(self, needsLayoutOriginalSelector,needsLayoutSwizzleSelector);
SEL needsDisplaOriginalSelector = @selector(setNeedsDisplay);
SEL needsDisplaSwizzleSelector = @selector(guard_setNeedsDisplay);
swizzling_exchangeMethod(self, needsDisplaOriginalSelector,needsDisplaSwizzleSelector);
SEL needsDisplayInRectOriginalSelector = @selector(setNeedsDisplayInRect:);
SEL needsDisplayInRectSwizzleSelector = @selector(guard_setNeedsDisplayInRect:);
swizzling_exchangeMethod(self, needsDisplayInRectOriginalSelector,needsDisplayInRectSwizzleSelector);
});
}
- (void)guard_setNeedsLayout
{
[self UIMainThreadCheck];
[self guard_setNeedsLayout];
}
- (void)guard_setNeedsDisplay
{
[self UIMainThreadCheck];
[self guard_setNeedsDisplay];
}
- (void)guard_setNeedsDisplayInRect:(CGRect)rect
{
[self UIMainThreadCheck];
[self guard_setNeedsDisplayInRect:rect];
}
- (void)UIMainThreadCheck
{
NSString *desc = [NSString stringWithFormat:@"%@", self.class];
NSAssert([NSThread isMainThread], desc);
}
@end
