NSTimer 滑动导致失效

关键地方：

1.封装一个NSTimer  作用：防止循环引用

2.NStimer 在滑动时停止运行，

解决方法：1.通过修改timer默认mode, NSRunLoopCommonModes(滑动时主线程会从NSDefaultRunLoopMode切换为UITrackingRunLoopMode，导致timer停止运行)

[[NSRunLoop currentRunLoop] addTimer:timer forMode:NSRunLoopCommonModes];

2.通过创建子线程。

[NSThread detachNewThreadWithBlock:^{
        timerTarget.timer = [NSTimer scheduledTimerWithTimeInterval:interval
                                                             target:timerTarget
                                                           selector:@selector(timeAction:)
                                                           userInfo:userInfo
                                                            repeats:repeats];
        [[NSRunLoop currentRunLoop] addTimer:timerTarget.timer forMode:NSDefaultRunLoopMode];
        
        [[NSRunLoop currentRunLoop] run];
    }];

封装NStimer:

//
//  HSTimer.m
//  sad
//
//  Created by xc on 2022/8/9.
//
 
#import "HSTimer.h"
 
@interface HSTimerTarget : NSObject
@property (nonatomic, weak) id target;
@property (nonatomic, assign) SEL selector;
@property (nonatomic, weak) NSTimer* timer;
@end
 
@implementation HSTimerTarget
- (void)timeAction:(NSTimer *)timer {
    if(self.target) {
        [self.target performSelector:self.selector withObject:timer.userInfo afterDelay:0.0f];
    } else {
        [self.timer invalidate];
    }
}
@end
 
@implementation HSTimer
+ (NSTimer *) scheduledTimerWithTimeInterval:(NSTimeInterval)interval
                                      target:(id)aTarget
                                    selector:(SEL)aSelector
                                    userInfo:(id)userInfo
                                     repeats:(BOOL)repeats {
    HSTimerTarget* timerTarget = [[HSTimerTarget alloc] init];
    timerTarget.target = aTarget;
    timerTarget.selector = aSelector;
   
    [NSThread detachNewThreadWithBlock:^{
        timerTarget.timer = [NSTimer scheduledTimerWithTimeInterval:interval
                                                             target:timerTarget
                                                           selector:@selector(timeAction:)
                                                           userInfo:userInfo
                                                            repeats:repeats];
        [[NSRunLoop currentRunLoop] addTimer:timerTarget.timer forMode:NSDefaultRunLoopMode];
        
        [[NSRunLoop currentRunLoop] run];
    }];
    return timerTarget.timer;
}
 
@end
 

//
//  HSTimer.h
//  sad
//
//  Created by xc on 2022/8/9.
//
 
#import 
 
NS_ASSUME_NONNULL_BEGIN
 
@interface HSTimer : NSObject
 
+ (NSTimer *) scheduledTimerWithTimeInterval:(NSTimeInterval)interval
                                      target:(id)aTarget
                                    selector:(SEL)aSelector
                                    userInfo:(id)userInfo
                                     repeats:(BOOL)repeats;
@end
 
NS_ASSUME_NONNULL_END

使用：

注意点：在主线程刷新ui

- (NSTimer *)timer {
    if (!_timer) {
        _timer =
        _timer = [HSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(timeEvent) userInfo:@{@"":@""} repeats:YES];
    }
    return _timer;
}
 
 
- (void)timeEvent {
    SK_WeakSelf(self)
    dispatch_async(dispatch_get_main_queue(), ^{
        weakself.count--;//时间减少
        weakself.lab.text = [NSString stringWithFormat:@"%ld:%02ld",weakself.count/60,weakself.count%60];
        if (weakself.count == 0) {
            //到达时间以后取消定时器
            weakself.lab.text = @"去领取";
            [weakself stopTimer];
            if (weakself.progressOver) {
                weakself.progressOver();
            }
        }
        if (weakself.count <= timeNum) {
            CGFloat prose = (CGFloat)weakself.count/timeNum;
            
            [weakself setProgress:prose];
            
        }
        
        [weakself setNeedsDisplay];
    });
}