使用NSTimer和CGAffineTransformMakeRotation实现旋转动画

使用NSTimer和CGAffineTransformMakeRotation实现旋转动画

首先定义需要用到的变量

    float angle;
    NSTimer* timer;

#pragma mark ------------------->旋转图片<-------------------
- (void)_doRotateImage{
    //演员初始化
    UIImageView* ivImage = [[UIImageView alloc] init];
    UIImage* img = [UIImage imageNamed:@"image_loading"];
    ivImage.image=img;
    ivImage.frame=CGRectMake(100, 200, img.size.width, img.size.height);
    ivImage.center=self.view.center;
    ivImage.userInteractionEnabled=YES;
    ivImage.tag=9999;
    [self.view addSubview:ivImage];
    //初始化定时器NSTimer
    timer =[NSTimer scheduledTimerWithTimeInterval:0.01 target:self selector:@selector(_doOnTimer) userInfo:nil repeats:YES];
    
    //添加一个按钮用来暂停、开始定时器
    UIButton* btnTimer = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    [btnTimer setTitle:@"暂停" forState:UIControlStateNormal];
    [btnTimer setTitle:@"开启" forState:UIControlStateSelected];
    [btnTimer addTarget:self action:@selector(_doPauseOrStartTimer:) forControlEvents:UIControlEventTouchUpInside];
    btnTimer.frame=CGRectMake(100, 340, 100, 40);
    [self.view addSubview:btnTimer];
}

#pragma mark 定时器的触发事件
-(void) _doOnTimer{
    UIView* view = [self.view.window viewWithTag:9999];
    angle = angle + 0.05;//angle角度 double angle;
    if (angle > 6.28) {//大于 M_PI*2(360度) 角度再次从0开始
        angle = 0;
    }
    CGAffineTransform transform=CGAffineTransformMakeRotation(angle);
    view.transform = transform;
}


-(void) _doPauseOrStartTimer:(UIButton*) sender{
    
    if (sender.selected) {
        [timer setFireDate:[NSDate distantPast]];
    }else{
        [timer setFireDate:[NSDate distantFuture]];
    }
    sender.selected=!sender.selected;
    
}

效果图如下：