iOS NSTimer循环引用的办法

#import "LXFTimerView.h"
@interface LXFTimerView()
/** 定时器 */
@property(nonatomic, weak) NSTimer *timer;
@end

@implementation LXFTimerView
- (instancetype)initWithFrame:(CGRect)frame {
  if (self = [super initWithFrame:frame]) {
    [self addTimer];
  }
  return self;
}

- (void)dealloc {
  NSLog(@"LXFTimerView - dealloc");
  [self removeTimer];
}

#pragma mark - 定时器方法
/** 添加定时器方法 */
- (void)addTimer {
  // 创建定时器
  if (self.timer) { return; }
  self.timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(log) userInfo:nil repeats:YES];
  [[NSRunLoop currentRunLoop] addTimer:self.timer forMode:NSRunLoopCommonModes];
}
/** 移除定时器 */
- (void)removeTimer {
  [self.timer invalidate];
  self.timer = nil;
}
- (void)log {
  NSLog(@"定时器 -- %s", __func__);
}
@end

#import "ViewController.h"
#import "LXFTimerView.h"
@interface ViewController ()
/** timerView */
@property(nonatomic, weak) LXFTimerView *timerView;
@end

@implementation ViewController
- (void)viewDidLoad {
  [super viewDidLoad];
  LXFTimerView *timerView = [[LXFTimerView alloc] initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, 200)];
  timerView.backgroundColor = [UIColor orangeColor];
  self.timerView = timerView;
  [self.view addSubview:timerView];  
}
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
  [self.timerView removeFromSuperview];
}
@end

[NSTimer scheduledTimerWithTimeInterval: target: selector: userInfo: repeats:];

#import <Foundation/Foundation.h>
@interface LXFWeakTarget : NSObject
+ (NSTimer *)scheduledTimerWithTimeInterval:(NSTimeInterval)ti target:(id)aTarget selector:(SEL)aSelector userInfo:(nullable id)userInfo repeats:(BOOL)yesOrNo;
@end

#import "LXFWeakTarget.h"

@interface LXFWeakTarget()
@property(nonatomic, weak) id target;
@property(nonatomic, assign) SEL selector;
@end

@implementation LXFWeakTarget
+ (NSTimer *)scheduledTimerWithTimeInterval:(NSTimeInterval)ti target:(id)aTarget selector:(SEL)aSelector userInfo:(nullable id)userInfo repeats:(BOOL)yesOrNo {
  // 创建当前类的对象
  LXFWeakTarget *object = [[LXFWeakTarget alloc] init];
  object.target = aTarget;
  object.selector = aSelector;

  return [NSTimer scheduledTimerWithTimeInterval:ti target:object selector:@selector(execute:) userInfo:userInfo repeats:yesOrNo];
}
- (void)execute:(id)obj {
  [self.target performSelector:self.selector withObject:obj]; 
}
@end

#import "LXFWeakTarget.h"