iOS仿高德首页推拉效果实例代码

    SlideView * slideView = [[SlideView alloc] initWithFrame:CGRectMake(0, kScreenHeight-140, kScreenWidth, kScreenHeight-100)];
    slideView.topH = 100;
    [self.view addSubview:slideView];

    UIPanGestureRecognizer * panGestureRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panAction:)];
    panGestureRecognizer.delegate = self;
    [self addGestureRecognizer:panGestureRecognizer];

    self.tableView.bounces = NO;
    self.tableView.userInteractionEnabled = NO;

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
    return YES;
}

-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    CGFloat currentPostion = scrollView.contentOffset.y;
    self.stop_y = currentPostion;
}

- (void)panAction:(UIPanGestureRecognizer *)pan
{
    // 获取视图偏移量
    CGPoint point = [pan translationInView:self];
    // stop_y是tableview的偏移量，当tableview的偏移量大于0时则不去处理视图滑动的事件
    if (self.stop_y>0) {
        // 将视频偏移量重置为0
        [pan setTranslation:CGPointMake(0, 0) inView:self];
        return;
    }
    
    // self.top是视图距离顶部的距离
    self.top += point.y;
    if (self.top < self.topH) {
        self.top = self.topH;
    }
    
    // self.bottomH是视图在底部时距离顶部的距离
    if (self.top > self.bottomH) {
        self.top = self.bottomH;
    }
    
    // 在滑动手势结束时判断滑动视图距离顶部的距离是否超过了屏幕的一半，如果超过了一半就往下滑到底部
    // 如果小于一半就往上滑到顶部
    if (pan.state == UIGestureRecognizerStateEnded || pan.state == UIGestureRecognizerStateCancelled) {
        
        // 滑动速度
        CGPoint velocity = [pan velocityInView:self];
        CGFloat speed = 350;
        if (velocity.y < -speed) {
            [self goTop];
            [pan setTranslation:CGPointMake(0, 0) inView:self];
            return;
        }else if (velocity.y > speed){
            [self goBack];
            [pan setTranslation:CGPointMake(0, 0) inView:self];
            return;
        }
        
        if (self.top > kScreenHeight/2) {
            [self goBack];
        }else{
            [self goTop];
        }
    }
    
    [pan setTranslation:CGPointMake(0, 0) inView:self];
}

- (void)goTop {
    [UIView animateWithDuration:0.5 animations:^{
        self.top = self.topH;
    }completion:^(BOOL finished) {
        self.tableView.userInteractionEnabled = YES;
    }];
}

- (void)goBack {
    [UIView animateWithDuration:0.5 animations:^{
        self.top = self.bottomH;
    }completion:^(BOOL finished) {
        self.tableView.userInteractionEnabled = NO;
    }];
}

-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    CGFloat currentPostion = scrollView.contentOffset.y;
    self.stop_y = currentPostion;
    
    if (self.top>self.topH) {
        [scrollView setContentOffset:CGPointMake(0, 0)];
    }
}