CADisplayLink、NSTimer使用注意
CADisplayLink、NSTimer会对target产生强引用，如果target又对它们产生强引用，那么就会引发循环引用
- 解决方案
- 使用block
__weak typeof(self) weakSelf = self;
self.timer = [NSTimer scheduledTimerWithTimeInterval:1.0 repeats:YES block:^(NSTimer * _Nonnull timer) {
[weakSelf timerTest];
}];
- 使用代理对象（NSProxy）
#import <Foundation/Foundation.h>
@interface WDProxy : NSObject
+ (instancetype)proxyWithTarget:(id)target;
@property (weak, nonatomic) id target;
@end
#import "WDProxy.h"
@implementation WDProxy
+ (instancetype)proxyWithTarget:(id)target
{
WDProxy *proxy = [[WDProxy alloc] init];
proxy.target = target;
return proxy;
}
- (id)forwardingTargetForSelector:(SEL)aSelector
{
return self.target;
}
@end
或者继承NSProxy，使用效率更高
@interface WDProxy : NSProxy
+ (instancetype)proxyWithTarget:(id)target;
@property (weak, nonatomic) id target;
@end
#import "WDProxy.h"
@implementation WDProxy
+ (instancetype)proxyWithTarget:(id)target
{
// NSProxy对象不需要调用init，因为它本来就没有init方法
WDProxy *proxy = [WDProxy alloc];
proxy.target = target;
return proxy;
}
- (NSMethodSignature *)methodSignatureForSelector:(SEL)sel
{
return [self.target methodSignatureForSelector:sel];
}
- (void)forwardInvocation:(NSInvocation *)invocation
{
[invocation invokeWithTarget:self.target];
}
@end
使用
self.link = [CADisplayLink displayLinkWithTarget:[WDProxy proxyWithTarget:self] selector:@selector(linkTest)];
[self.link addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];
self.timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:[WDProxy proxyWithTarget:self] selector:@selector(timerTest) userInfo:nil repeats:YES];
